AIM: To discuss the changes of intestinal mucosal immune function in rats with experimental severe acute pancreatitis(SAP) and the regulatory effect of L-arginine.METHODS: Male adult Wistar rats were randomly divided ...AIM: To discuss the changes of intestinal mucosal immune function in rats with experimental severe acute pancreatitis(SAP) and the regulatory effect of L-arginine.METHODS: Male adult Wistar rats were randomly divided into pancreatitis group, sham-operation group, and L-arginine treatment group. Animals were killed at 24, 48, and 72 h after SAP models were developed and specimens were harvested. Endotoxin concentration in portal vein was determined by limulus endotoxin analysis kit. CD3+, CD4+,CD8+ T lymphocytes in intestinal mucosal lamina propria were examined by immunohistochemistry. Secretory immunoglobulin A (SIgA) in cecum feces was examined by radioimmunoassay.RESULTS: Compared to the control group, plasma endotoxin concentration in the portal vein increased, percentage of CD3+ and CD4+ T lymphocyte subsets in the end of intestinal mucosal lamina propria reduced significantly,CD4+/CD8+ ratio decreased, and SIgA concentrations in cecum feces reduced at 24, 48, and 72 h after SAP developed. Compared to SAP group, the L-arginine treatment group had a lower level of plasma endotoxin concentration in the portal vein, a higher CD3+ and CD4+ T lymphocyte percentage in the end of intestinal mucosal lamina propria,an increased ratio of CD4+/CD8+ and a higher SIgA concentration in cecum feces.CONCLUSION: Intestinal immune suppression occurs in the early stage of SAP rats, which may be the main reason for bacterial and endotoxin translocation. L-arginine can improve the intestinal immunity and reduce bacterial and endotoxin translocation in SAP rats.展开更多
BACKGROUND: Post-transplantation pancreatitis andgraft thrombosis are two major complications of pancreastrans-plantation that contribute to morbidity, mortality, andgraft loss. Nitric oxide (NO) is a potent vasodilat...BACKGROUND: Post-transplantation pancreatitis andgraft thrombosis are two major complications of pancreastrans-plantation that contribute to morbidity, mortality, andgraft loss. Nitric oxide (NO) is a potent vasodilator agentformed when L-arginine ( L-Arg) is converted to L-citrul-line by the action of NO synthase (NOS), and plays a ma-jor role in microcirculatory changes. We therefore investi-gated the effect of L-Arg on reperfusion injury followingpancreaticoduodenal transplantation in rats.METHODS: The homologous male Wistar rat model ofheterotopic total pancreaticoduodenal transplantation wasused. The L-Arg-treated rats received the intravenous in-jection of L-Arg 5 minutes before and after reperfusion at adose of 200 mg/kg while the N-Nitro-L-arginine methyl es-ter (L-NAME) -treated rats at a dose of 10 mg/kg. Theamount of NO in the pancreas graft was measured. Serumconcentration of cytokine-induced neutrophil chemoattrac-tant ( CINC) was determined by enzyme-linked immu-nosorbant assay, the expression of CINC mRNA was detect-ed by Northern blot assay in the pancreas graft, and the ac-tivity of myeloperoxidase (MPO) was measured. Histolo-gical examination was performed.RESULTS: The amount of NO was higher in the L-Arggroup than in the control group, while it was lower in theL-NAME group than in the control group (P <0.05). Thepeak of serum CINC concentration occurred 3 hours afterreperfusion with the difference among the groups being sig-nificant. The expression peak of CINC mRNA in the pan-creas graft occurred 3 hours after reperfusion. The expres-sion level in the L-Arg group (7.66 ± 1.53 μg/L) was lowerthan in the control group (26.31±2.01 μg/L), while in theL-NAME group (34.18 ±3.12 μg/L) it was higher than thatin the control group (P <0. 05). The activity of MPO inthe L-Arg group was obviously decreasd as compared within the other groups. The pancreas inflammation was ame-liorated when L-Arg was administered, whereas the panc-reas damage was aggravated when L-NAME was adminis-tered.CONCLUSIONS: L-Arg can increase the amount of NOand inhibit the elevation of CINC, the CINC mRNA ex-pression and early neutrophil accumulation in the pancreas.NO has protective effects on ischemia/reperfusion injury inpancreaticoduodenal transplantation.展开更多
AIM: To investigate the role of Sonic hedgehog (Shh) on the course of liver ischemia and reperfusion (I/R) in rats, and the interaction between treatment with nitric oxide donor L-Arginine-methyl ester (L-Arg) and up-...AIM: To investigate the role of Sonic hedgehog (Shh) on the course of liver ischemia and reperfusion (I/R) in rats, and the interaction between treatment with nitric oxide donor L-Arginine-methyl ester (L-Arg) and up-regulation of Shh expression. METHODS: A total of 30 male Sprague-Dawley rats weighing 220-240 g were used in this study. Sham-control group (G1, n = 10): a sham operation was performed (except for liver I/R). I/R-untreated group (G2, n = 10): rats underwent liver ischemia for 1 h followed by reperfusion for 45 min. I/R-L-Arg group (G3, n = 10): after performing the same surgical procedure as in group 2, animals were treated with L-Arg. Liver tissues were taken for determination of malondialdehyde (MDA) levels, and biochemical and histological evaluations were made. RESULTS: Plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and γ-glutamyltranspeptidase (GGT) activities were higher in group 2 than in group 3. MDA values and the hepatic injury score decreased in the L-Arg treated group compared to the I/R-untreated group. In group 2, the hepatocytes were swollen with marked vacuolization. Group 3 rats showed well-preserved liver parenchyma, with hepatocytes extending from the central vein. The morphology of the hepatocytes and the sinusoidal structures was normal, without any signs of congestion. Mild Shh positive immunostaining was detected in group 2 animals. The expression of immunoreactive cells was increased markedly in liver tissue from I/R-L-Arg rats.CONCLUSION: Our findings suggest that Shh molecules are critical factors in the pathophysiology of inflammatory liver injury induced by I/R. In addition, NO plays an important role in the immunohistochemical expression of these molecules.展开更多
AIM: Small intestinal ischemia-reperfusion (IR) has been demonstrated to result in both local mucosal injury and systemic injuries. The exact role of nitric oxide (NO) in intestinal IR is unclear. We propose that NO a...AIM: Small intestinal ischemia-reperfusion (IR) has been demonstrated to result in both local mucosal injury and systemic injuries. The exact role of nitric oxide (NO) in intestinal IR is unclear. We propose that NO and some other cytokines change in the reperfusion period and these changes are associated with lung injury. The aim of this study was to determine the effect of supplementing NO substrate, L-arginine (L-arg), on serum and pulmonary cytokine production during small intestinal IR in immature rats.METHODS: Immature rats underwent 60 min. of superior mesenteric artery occlusion followed by 90 min of reperfusion. L-arg (250 mg/kg) was given intravenously to the experimental group (IR+L-arg) which received L-arg after 45 min of intestinal ischemia. Serum and lung endothelin-1 (ET-1), NO, malondialdehyde (MDA), and tumor necrosis factor α (TNFα) were measured. Sham operation (SHAM) and intestinal IR (IR) groups were performed as control. The lavage fluid of the lung was collected by bronchoalveolar lavage (BAL) and white blood cells and polymorphonuclear cells (PMNs) were immediately counted to identify lung damage.RESULTS: When L-arg was given during small intestinal IR, serum NO concentration increased significantly in IR+L-arg group (162.17±42.93 μmol/L) when compared with IR group (87.57±23.17 μmol/L, t= 3.190, P = 0.008＜0.01). Serum MDA reduced significantly in IR+L-arg group (8.93±1.50 nmol/L) when compared with SHAM(23.78±7.81 nmol/L, t = 3.243, P = 0.007＜0.01) and IR (25.54±9.32 nmol/L, t = 3.421, P = 0.006＜0.01).ET-1 level in lung tissues was significantly lower in IR+L-arg group (13.81±7.84 pg/mL) than that in SHAM(35.52±10.82 pg/mL, t = 2.571, P= 0.03＜0.05) and IR(50.83±22.05 pg/mL, t = 3.025, P = 0.009＜0.01) groups.MDA contents in lung tissues were significantly lower in IR+L-arg group (10.73±1.99 nmol/L) than in SHAM(16.62±2.28 nmol/L, t = 3.280, P = 0.007＜0.01) and IR(21.90±4.82 nmol/L, t= 3.322, P= 0.007＜0.01)groups.Serum and lung TNFα concentrations were not significantly different in three groups. NO contents in lung homogenates and white blood cell counts in BAL had no significant difference in three groups; but the percentage of PMNs in BAL was 13.50±8.92, 33.20±16.59, and 22.50±6.09 in SHAM, IR, and IR+L-arg groups, respectively.CONCLUSION: Small intestinal IR induced increases of pulmonary neutrophil infiltration in immature rats.Neutrophil infiltration in lung tissues was reduced by L-arg administration but remained higher than in SHAM group.L-arg administration during intestinal IR enhances serum NO production, reduces serum MDA and lung ET-1 and MDA levels, resulting in the improvement of systemic endothelial function. L-arg supplementation before reperfusion may act as a useful clinical adjunct in the management of intestinal IR, thus preventing the development of adult respiratory distress syndrome, even multiple organ dysfunction syndrome (MODS).展开更多
Objective In Corynebacterium crenatum,the adjacent D311 and D312 of N-acetyl-L-glutamate kinase(NAGK),as a key rate-limiting enzyme of L-arginine biosynthesis under substrate regulatory control by arginine,were initia...Objective In Corynebacterium crenatum,the adjacent D311 and D312 of N-acetyl-L-glutamate kinase(NAGK),as a key rate-limiting enzyme of L-arginine biosynthesis under substrate regulatory control by arginine,were initially replaced with two arginine residues to investigate the L-arginine feedback inhibition for NAGK.Methods NAGK enzyme expression was evaluated using a plasmid-based method.Homologous recombination was employed to eliminate the pro B.Results The IC50 and enzyme activity of NAGK M4,in which the D311 R and D312 R amino acid substitutions were combined with the previously reported E19 R and H26 E substitutions,were 3.7-fold and 14.6% higher,respectively,than those of the wild-type NAGK.NAGK M4 was successfully introduced into the C.crenatum MT genome without any genetic markers;the L-arginine yield of C.crenatum MT-M4 was 26.2% higher than that of C.crenatum MT.To further improve upon the L-arginine yield,we constructed the mutant C.crenatum MT-M4 ?pro B.The optimum concentration of L-proline was also investigated in order to determine its contribution to L-arginine yield.After L-proline was added to the medium at 10 mmol/L,the L-arginine yield reached 16.5 g/L after 108 h of shake-flask fermentation,approximately 70.1% higher than the yield attained using C.crenatum MT.Conclusion Feedback inhibition of L-arginine on NAGK in C.crenatum is clearly alleviated by the M4 mutation of NAGK,and deletion of the pro B in C.crenatum from MT to M4 results in a significant increase in arginine production.展开更多
AIM: To investigate the protective effect and possible mechanism of L-arginine preconditioning on ischemia and reperfusion injury associated with small bowel transplantation (SBT).METHODS: Male inbred Wistar rats weig...AIM: To investigate the protective effect and possible mechanism of L-arginine preconditioning on ischemia and reperfusion injury associated with small bowel transplantation (SBT).METHODS: Male inbred Wistar rats weighting between 180 and 250 g were used as donors and recipients in thestudy. Heterotopic rat SBT was performed according to the techniques of Li and Wu. During the experiment, intestinal grafts were preserved in 4 ℃ Ringer's solution for 8 h before being transplanted. Animals were divided into three groups. In group 1, donors received intravenous L-arginine (50 mg/kg, 1 mL) injection 90 min before graft harvesting. However, donors in control group were given normal saline (NS) instead. In group 3, six rats were used as sham-operated control. Specimens were taken from intestinal grafts 15 min after reperfusion. Histological grading, tissue malondialdehyde (MDA) and myeloperoxidase (MPO) levels were assessed. The graft survival of each group was monitored daily until 14 d after transplantation. RESULTS: Levels of MDA and MPO in intestine of shamoperated rats were 2.0±0.22 mmol/g and 0.66±0.105 U/g. Eight hours of cold preservation followed by 15 min of reperfusion resulted in significant increases in tissue MDA and MPO levels. Pretreatment with L-arginine before graft harvesting resulted in lower enhancement of tissue levels of MDA and MPO and the differences were significant (4.71±1.02 mmol/g vs8.02±3.49 mmol/g, 1.03±0.095 U/g vs 1.53±0.068 U/g, P＜0.05). Besides, animals in L-arginine pretreated group had better histological structures and higher 2-wk graft survival rates comparing with that in NS treated group (3.3±0.52 vs6±0.1, 0/6 vs6/6, P＜0.05or 0.01).CONCLUSION: L-arginine preconditioning attenuates ischemia and reperfusion injury in the rat SBT model,which was due to antioxidant activities partially.展开更多
AIM To counteract/reveal celecoxib-induced toxicity and NO system involvement. METHODS Celecoxib(1 g/kg b.w. ip) was combined with therapy with stable gastric pentadecapeptide BPC 157(known to inhibit these lesions, ...AIM To counteract/reveal celecoxib-induced toxicity and NO system involvement. METHODS Celecoxib(1 g/kg b.w. ip) was combined with therapy with stable gastric pentadecapeptide BPC 157(known to inhibit these lesions, 10 μg/kg, 10 ng/kg, or 1 ng/kg ip) and L-arginine(100 mg/kg ip), as well as NOS blockade [N(G)-nitro-L-arginine methyl ester(L-NAME)](5 mg/kg ip) given alone and/or combined immediately after celecoxib. Gastrointestinal, liver, and brain lesions and liver enzyme serum values in rats were assessed at 24 h and 48 h thereafter. RESULTS This high-dose celecoxib administration, as a result of NO system dysfunction, led to gastric, liver, and brain lesions and increased liver enzyme serum values. The L-NAME-induced aggravation of the lesions was notable for gastric lesions, while in liver and brain lesions the beneficial effect of L-arginine was blunted. L-arginine counteracted gastric, liver and brain lesions. These findings support the NO system mechanism(s), both NO system agonization(L-arginine) and NO system antagonization(L-NAME), that on the whole are behind all of these COX phenomena. An even more complete antagonization was identified with BPC 157(at both 24 h and 48 h). A beneficial effect was evident on all the increasingly negative effects of celecoxib and L-NAME application and in all the BPC 157 groups(L-arginine + BPC 157; L-NAME + BPC 157; L-NAME + L-arginine + BPC 157). Thus, these findings demonstrated that BPC 157 may equally counteract both COX-2 inhibition(counteracting the noxious effects of celecoxib on all lesions) and additional NOS blockade(equally counteracting the noxious effects of celecoxib + L-NAME). CONCLUSION BPC 157 and L-arginine alleviate gastrointestinal, liver and brain lesions, redressing NSAIDs' post-surgery application and NO system involvement.展开更多
AIM To cure typically life-threatening esophagogastric anastomosis in rats, lacking anastomosis healing and sphincter function rescue, in particular. METHODS Because we assume esophagogastric fistulas represent a part...AIM To cure typically life-threatening esophagogastric anastomosis in rats, lacking anastomosis healing and sphincter function rescue, in particular. METHODS Because we assume esophagogastric fistulas represent a particular NO-system disability, we attempt to identify the benefits of anti-ulcer stable gastric pentadecapeptide BPC 157, which was in trials for ulcerative colitis and currently for multiple sclerosis, in rats with esophagocutaneous fistulas. Previously, BPC 157 therapies have promoted the healing of intestinal anastomosis and fistulas, and esophagitis and gastric lesions, along with rescued sphincter function. Additionally, BPC 157 particularly interacts with the NOsystem. In the 4 d after esophagogastric anastomosis creation, rats received medication(/kg intraperitoneallyonce daily: BPC 157(10 μg, 10 ng), L-NAME(5 mg), or L-arginine(100 mg) alone and/or combined or BPC 157(10 μg, 10 ng) in drinking water). For rats underwent esophagogastric anastomosis, daily assessment included progressive stomach damage(sum of the longest diameters, mm), esophagitis(scored 0-5), weak anastomosis(m L H2 O before leak), low pressure in esophagus at anastomosis and in the pyloric sphincter(cm H2O), progressive weight loss(g) and mortality. Immediate effect assessed blood vessels disappearance(scored 0-5) at the stomach surface immediately after anastomosis creation. RESULTS BPC 157(all regimens) fully counteracted the perilous disease course from the very beginning(i.e., with the BPC 157 bath, blood vessels remained present at the gastric surface after anastomosis creation) and eliminated mortality. Additionally, BPC 157 treatment in combination with L-NAME nullified any effect of L-NAME that otherwise intensified the regular course. Consistently, with worsening(with L-NAME administration) and amelioration(with L-arginine), either L-arginine amelioration prevails(attenuated esophageal and gastric lesions) or they counteract each other(L-NAME + L-arginine); with the addition of BPC 157(L-NAME + L-arginine + BPC 157), there was a marked beneficial effect. BPC 157 treatment for esophagogastric anastomosis, along with NOS-blocker L-NAME and/or NOS substrate L-arginine, demonstrated an innate NO-system disability(as observed with L-arginine effectiveness). BPC 157 distinctively affected corresponding events: worsening(obtained with L-NAME administration that was counteracted); or amelioration(L-arginine + BPC 157-rats correspond to BPC 157-rats).CONCLUSION Innate NO-system disability for esophagogastric anastomoses, including L-NAME-worsening, suggests that these effects could be corrected by L-arginine and almost completely eliminated by BPC 157 therapy.展开更多
Exhaled breath nitric oxide (NO) is an accepted asthma biomarker.Lung concentrations of NO and its amino acid precursor,L-arginine,are regulated by the relative expressions of the NO synthase (NOS) and arginase isofor...Exhaled breath nitric oxide (NO) is an accepted asthma biomarker.Lung concentrations of NO and its amino acid precursor,L-arginine,are regulated by the relative expressions of the NO synthase (NOS) and arginase isoforms.Increased expression of arginase I and NOS2 occurs in murine models of allergic asthma and in biopsies of asthmatic airways.Although clinical trials involving the inhibition of NO-producing enzymes have shown mixed results,small molecule arginase inhibitors have shown potential as a therapeutic intervention in animal and cell culture models.Their transition to clinical trials is hampered by concerns regarding their safety and potential toxicity.In this review,we discuss the paradigm of arginase and NOS competition for their substrate L-arginine in the asthmatic airway.We address the functional role of L-arginine in inflammation and the potential role of arginase inhibitors as therapeutics.展开更多
A novel poly-l-arginine microcapsule was prepared due to its nutritional function and pharmacological efficacy. A high-voltage electrostatic droplet generator was used to make uniform microcapsules. The results show t...A novel poly-l-arginine microcapsule was prepared due to its nutritional function and pharmacological efficacy. A high-voltage electrostatic droplet generator was used to make uniform microcapsules. The results show that the membrane strength and permeating property are both remarkably affected with the changes of sodium alginate concentration. With the sodium alginate concentration increasing, gel beads sizes increase from 233μtm to 350μtm, release ratio is also higher at the same time, but the membrane strength decreases.展开更多
BACKGROUND:Although the use of non-heart beating donors(NHBDs)could bridge the widening gap between organ demand and supply,its application to liver transplantation is limited due to the high incidence of primary graf...BACKGROUND:Although the use of non-heart beating donors(NHBDs)could bridge the widening gap between organ demand and supply,its application to liver transplantation is limited due to the high incidence of primary graft loss.Prevention of liver injury in NHBDs will benefit the results of transplantation.This study was conducted to evaluate the protective effects of L-arginine on liver grafts from NHBDs. METHODS:One hundred and four Wistar rats were randomly divided into 7 groups:normal control(n=8) controls 1,2 and 3(C1,C2,C3,n=16),and experimenta 1,2 and 3(E1,E2,E3,n=16).For groups C1 and E1,C2 and E2,and C3 and E3,the warm ischemia time was 0,30,and 45 minutes,respectively.Liver grafts were flushed with and preserved in 4℃Euro-collins solution containing 1 mmol/L L-arginine for 1 hour in each experimental group Recipients of each experimental group were injected with L-arginine(10 mg/kg body weight)by tail vein 10 minutes before portal vein reperfusion.Donors and recipients of each experimental control group were treated with norma saline.Then transplantation was performed.At 1,3,and 24 hours after portal vein reperfusion,blood samples were obtained to determine the levels of alanine aminotransferase (ALT),aspartate aminotransferase(AST),nitric oxide (NO)and plasma endothelin(ET).At 3 hours after porta vein reperfusion,grafts samples were fixed in 2.5% glutaraldehyde for electron microscopic observation.RESULTS:At 1 hour after portal vein reperfusion,the levels of NO in groups E1,E2,E3 and C1,C2,C3 were lower,while the levels of plasma ET,serum ALT and AST were higher than those in the normal control group(P<0.05).At 1,3,and 24 hours,the levels of NO in groups E1,E2,E3 were higher,while the levels of plasma ET,serum ALT and AST were lower than those in the corresponding control groups(C1,C2,C3) (P<0.05).The levels of NO in groups C2 and C3 were lower than in group C1(P<0.05),and the level of NO in group C3 was lower than in group C2(P<0.05).At 1,3 and 24 hours, the levels of plasma ET,serum ALT,and AST in groups E1, E2,E3 were lower than those in the corresponding control groups(C1,C2,C3)(P<0.05).The levels of plasma ET,serum ALT,and AST were lower in group C3 than in groups C1 and C2(P<0.05).Pathological changes in groups E1,E2,E3 were milder than those in the corresponding experimental control groups(C1,C2,C3). CONCLUSIONS:The imbalance between NO and ET plays an important role in the development of ischemia- reperfusion injury of liver grafts from NHBDs.L-arginine can attenuate injury in liver grafts from NHBDs by improving the balance between NO and ET.展开更多
AIM To study the counteraction of perforated cecum lesion using BPC 157 and nitric oxide(NO) system agents.METHODS Alongside with the agents' application(after 1 min, medication(/kg, 10 ml/2 min bath/rat) includes...AIM To study the counteraction of perforated cecum lesion using BPC 157 and nitric oxide(NO) system agents.METHODS Alongside with the agents' application(after 1 min, medication(/kg, 10 ml/2 min bath/rat) includes: BPC 157(10 μg), L-NAME(5 mg), L-arginine(100mg) alone or combined, and saline baths(controls)) on the rat perforate cecum injury, we continuously assessed the gross reappearance of the vessels(USB microcamera) quickly propagating toward the defect at the cecum surface, defect contraction, bleeding attenuation, MDA-and NO-levels in cecum tissue at 15 min, and severity of cecum lesions and adhesions at 1 and 7 d. RESULTS Post-injury, during/after a saline bath, the number of vessels was significantly reduced, the defect was slightly narrowed, bleeding was significant and MDA-levels increased and NO-levels decreased. BPC 157 bath: the vessel presentation was markedly increased, the defect was noticeably narrowed, the bleeding time was shortened and MDA-and NO-levels remained normal. L-NAME: reduced vessel presentation but not more than the control, did not change defect and shortened bleeding. L-arginine: exhibited less vessel reduction, did not change the defect and prolonged bleeding. In combination, mutual counteraction occurred(L-NAME + L-arginine) or the presentation was similar to that of BPC 157 rats(BPC 157 + L-NAME; BPC 157 + L-arginine; BPC 157 + L-NAME + L-arginine), except the defect did not change. Thereby at day 1 and 7, saline, L-NAME, L-arginine and L-NAME + L-arginine failed(defect was still open and large adhesions present). CONCLUSION The therapeutic effect was achieved with BPC 157 alone or in combination with L-NAME and L-arginine as it was able to consolidate the stimulating and inhibiting effects of the NO-system towards more effective healing recruiting vessels.展开更多
文摘AIM: To discuss the changes of intestinal mucosal immune function in rats with experimental severe acute pancreatitis(SAP) and the regulatory effect of L-arginine.METHODS: Male adult Wistar rats were randomly divided into pancreatitis group, sham-operation group, and L-arginine treatment group. Animals were killed at 24, 48, and 72 h after SAP models were developed and specimens were harvested. Endotoxin concentration in portal vein was determined by limulus endotoxin analysis kit. CD3+, CD4+,CD8+ T lymphocytes in intestinal mucosal lamina propria were examined by immunohistochemistry. Secretory immunoglobulin A (SIgA) in cecum feces was examined by radioimmunoassay.RESULTS: Compared to the control group, plasma endotoxin concentration in the portal vein increased, percentage of CD3+ and CD4+ T lymphocyte subsets in the end of intestinal mucosal lamina propria reduced significantly,CD4+/CD8+ ratio decreased, and SIgA concentrations in cecum feces reduced at 24, 48, and 72 h after SAP developed. Compared to SAP group, the L-arginine treatment group had a lower level of plasma endotoxin concentration in the portal vein, a higher CD3+ and CD4+ T lymphocyte percentage in the end of intestinal mucosal lamina propria,an increased ratio of CD4+/CD8+ and a higher SIgA concentration in cecum feces.CONCLUSION: Intestinal immune suppression occurs in the early stage of SAP rats, which may be the main reason for bacterial and endotoxin translocation. L-arginine can improve the intestinal immunity and reduce bacterial and endotoxin translocation in SAP rats.
基金This study was supported by a grant from foundation of Liaoning ProvincialKey Projects ( No. 0025001 ), China.
文摘BACKGROUND: Post-transplantation pancreatitis andgraft thrombosis are two major complications of pancreastrans-plantation that contribute to morbidity, mortality, andgraft loss. Nitric oxide (NO) is a potent vasodilator agentformed when L-arginine ( L-Arg) is converted to L-citrul-line by the action of NO synthase (NOS), and plays a ma-jor role in microcirculatory changes. We therefore investi-gated the effect of L-Arg on reperfusion injury followingpancreaticoduodenal transplantation in rats.METHODS: The homologous male Wistar rat model ofheterotopic total pancreaticoduodenal transplantation wasused. The L-Arg-treated rats received the intravenous in-jection of L-Arg 5 minutes before and after reperfusion at adose of 200 mg/kg while the N-Nitro-L-arginine methyl es-ter (L-NAME) -treated rats at a dose of 10 mg/kg. Theamount of NO in the pancreas graft was measured. Serumconcentration of cytokine-induced neutrophil chemoattrac-tant ( CINC) was determined by enzyme-linked immu-nosorbant assay, the expression of CINC mRNA was detect-ed by Northern blot assay in the pancreas graft, and the ac-tivity of myeloperoxidase (MPO) was measured. Histolo-gical examination was performed.RESULTS: The amount of NO was higher in the L-Arggroup than in the control group, while it was lower in theL-NAME group than in the control group (P <0.05). Thepeak of serum CINC concentration occurred 3 hours afterreperfusion with the difference among the groups being sig-nificant. The expression peak of CINC mRNA in the pan-creas graft occurred 3 hours after reperfusion. The expres-sion level in the L-Arg group (7.66 ± 1.53 μg/L) was lowerthan in the control group (26.31±2.01 μg/L), while in theL-NAME group (34.18 ±3.12 μg/L) it was higher than thatin the control group (P <0. 05). The activity of MPO inthe L-Arg group was obviously decreasd as compared within the other groups. The pancreas inflammation was ame-liorated when L-Arg was administered, whereas the panc-reas damage was aggravated when L-NAME was adminis-tered.CONCLUSIONS: L-Arg can increase the amount of NOand inhibit the elevation of CINC, the CINC mRNA ex-pression and early neutrophil accumulation in the pancreas.NO has protective effects on ischemia/reperfusion injury inpancreaticoduodenal transplantation.
文摘AIM: To investigate the role of Sonic hedgehog (Shh) on the course of liver ischemia and reperfusion (I/R) in rats, and the interaction between treatment with nitric oxide donor L-Arginine-methyl ester (L-Arg) and up-regulation of Shh expression. METHODS: A total of 30 male Sprague-Dawley rats weighing 220-240 g were used in this study. Sham-control group (G1, n = 10): a sham operation was performed (except for liver I/R). I/R-untreated group (G2, n = 10): rats underwent liver ischemia for 1 h followed by reperfusion for 45 min. I/R-L-Arg group (G3, n = 10): after performing the same surgical procedure as in group 2, animals were treated with L-Arg. Liver tissues were taken for determination of malondialdehyde (MDA) levels, and biochemical and histological evaluations were made. RESULTS: Plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and γ-glutamyltranspeptidase (GGT) activities were higher in group 2 than in group 3. MDA values and the hepatic injury score decreased in the L-Arg treated group compared to the I/R-untreated group. In group 2, the hepatocytes were swollen with marked vacuolization. Group 3 rats showed well-preserved liver parenchyma, with hepatocytes extending from the central vein. The morphology of the hepatocytes and the sinusoidal structures was normal, without any signs of congestion. Mild Shh positive immunostaining was detected in group 2 animals. The expression of immunoreactive cells was increased markedly in liver tissue from I/R-L-Arg rats.CONCLUSION: Our findings suggest that Shh molecules are critical factors in the pathophysiology of inflammatory liver injury induced by I/R. In addition, NO plays an important role in the immunohistochemical expression of these molecules.
基金Supported by The Natural Scientific Foundation of Shandong Province, No. Q99C13
文摘AIM: Small intestinal ischemia-reperfusion (IR) has been demonstrated to result in both local mucosal injury and systemic injuries. The exact role of nitric oxide (NO) in intestinal IR is unclear. We propose that NO and some other cytokines change in the reperfusion period and these changes are associated with lung injury. The aim of this study was to determine the effect of supplementing NO substrate, L-arginine (L-arg), on serum and pulmonary cytokine production during small intestinal IR in immature rats.METHODS: Immature rats underwent 60 min. of superior mesenteric artery occlusion followed by 90 min of reperfusion. L-arg (250 mg/kg) was given intravenously to the experimental group (IR+L-arg) which received L-arg after 45 min of intestinal ischemia. Serum and lung endothelin-1 (ET-1), NO, malondialdehyde (MDA), and tumor necrosis factor α (TNFα) were measured. Sham operation (SHAM) and intestinal IR (IR) groups were performed as control. The lavage fluid of the lung was collected by bronchoalveolar lavage (BAL) and white blood cells and polymorphonuclear cells (PMNs) were immediately counted to identify lung damage.RESULTS: When L-arg was given during small intestinal IR, serum NO concentration increased significantly in IR+L-arg group (162.17±42.93 μmol/L) when compared with IR group (87.57±23.17 μmol/L, t= 3.190, P = 0.008＜0.01). Serum MDA reduced significantly in IR+L-arg group (8.93±1.50 nmol/L) when compared with SHAM(23.78±7.81 nmol/L, t = 3.243, P = 0.007＜0.01) and IR (25.54±9.32 nmol/L, t = 3.421, P = 0.006＜0.01).ET-1 level in lung tissues was significantly lower in IR+L-arg group (13.81±7.84 pg/mL) than that in SHAM(35.52±10.82 pg/mL, t = 2.571, P= 0.03＜0.05) and IR(50.83±22.05 pg/mL, t = 3.025, P = 0.009＜0.01) groups.MDA contents in lung tissues were significantly lower in IR+L-arg group (10.73±1.99 nmol/L) than in SHAM(16.62±2.28 nmol/L, t = 3.280, P = 0.007＜0.01) and IR(21.90±4.82 nmol/L, t= 3.322, P= 0.007＜0.01)groups.Serum and lung TNFα concentrations were not significantly different in three groups. NO contents in lung homogenates and white blood cell counts in BAL had no significant difference in three groups; but the percentage of PMNs in BAL was 13.50±8.92, 33.20±16.59, and 22.50±6.09 in SHAM, IR, and IR+L-arg groups, respectively.CONCLUSION: Small intestinal IR induced increases of pulmonary neutrophil infiltration in immature rats.Neutrophil infiltration in lung tissues was reduced by L-arg administration but remained higher than in SHAM group.L-arg administration during intestinal IR enhances serum NO production, reduces serum MDA and lung ET-1 and MDA levels, resulting in the improvement of systemic endothelial function. L-arg supplementation before reperfusion may act as a useful clinical adjunct in the management of intestinal IR, thus preventing the development of adult respiratory distress syndrome, even multiple organ dysfunction syndrome (MODS).
基金supported by Natural Science Foundation of China,No.31360219 and No.30960012the Open Project Program of Key Laboratory of Functional Small Organic Molecule,Ministry of Education,Jiangxi Normal University(No.KLFS-KF-201414)
文摘Objective In Corynebacterium crenatum,the adjacent D311 and D312 of N-acetyl-L-glutamate kinase(NAGK),as a key rate-limiting enzyme of L-arginine biosynthesis under substrate regulatory control by arginine,were initially replaced with two arginine residues to investigate the L-arginine feedback inhibition for NAGK.Methods NAGK enzyme expression was evaluated using a plasmid-based method.Homologous recombination was employed to eliminate the pro B.Results The IC50 and enzyme activity of NAGK M4,in which the D311 R and D312 R amino acid substitutions were combined with the previously reported E19 R and H26 E substitutions,were 3.7-fold and 14.6% higher,respectively,than those of the wild-type NAGK.NAGK M4 was successfully introduced into the C.crenatum MT genome without any genetic markers;the L-arginine yield of C.crenatum MT-M4 was 26.2% higher than that of C.crenatum MT.To further improve upon the L-arginine yield,we constructed the mutant C.crenatum MT-M4 ?pro B.The optimum concentration of L-proline was also investigated in order to determine its contribution to L-arginine yield.After L-proline was added to the medium at 10 mmol/L,the L-arginine yield reached 16.5 g/L after 108 h of shake-flask fermentation,approximately 70.1% higher than the yield attained using C.crenatum MT.Conclusion Feedback inhibition of L-arginine on NAGK in C.crenatum is clearly alleviated by the M4 mutation of NAGK,and deletion of the pro B in C.crenatum from MT to M4 results in a significant increase in arginine production.
文摘AIM: To investigate the protective effect and possible mechanism of L-arginine preconditioning on ischemia and reperfusion injury associated with small bowel transplantation (SBT).METHODS: Male inbred Wistar rats weighting between 180 and 250 g were used as donors and recipients in thestudy. Heterotopic rat SBT was performed according to the techniques of Li and Wu. During the experiment, intestinal grafts were preserved in 4 ℃ Ringer's solution for 8 h before being transplanted. Animals were divided into three groups. In group 1, donors received intravenous L-arginine (50 mg/kg, 1 mL) injection 90 min before graft harvesting. However, donors in control group were given normal saline (NS) instead. In group 3, six rats were used as sham-operated control. Specimens were taken from intestinal grafts 15 min after reperfusion. Histological grading, tissue malondialdehyde (MDA) and myeloperoxidase (MPO) levels were assessed. The graft survival of each group was monitored daily until 14 d after transplantation. RESULTS: Levels of MDA and MPO in intestine of shamoperated rats were 2.0±0.22 mmol/g and 0.66±0.105 U/g. Eight hours of cold preservation followed by 15 min of reperfusion resulted in significant increases in tissue MDA and MPO levels. Pretreatment with L-arginine before graft harvesting resulted in lower enhancement of tissue levels of MDA and MPO and the differences were significant (4.71±1.02 mmol/g vs8.02±3.49 mmol/g, 1.03±0.095 U/g vs 1.53±0.068 U/g, P＜0.05). Besides, animals in L-arginine pretreated group had better histological structures and higher 2-wk graft survival rates comparing with that in NS treated group (3.3±0.52 vs6±0.1, 0/6 vs6/6, P＜0.05or 0.01).CONCLUSION: L-arginine preconditioning attenuates ischemia and reperfusion injury in the rat SBT model,which was due to antioxidant activities partially.
文摘AIM To counteract/reveal celecoxib-induced toxicity and NO system involvement. METHODS Celecoxib(1 g/kg b.w. ip) was combined with therapy with stable gastric pentadecapeptide BPC 157(known to inhibit these lesions, 10 μg/kg, 10 ng/kg, or 1 ng/kg ip) and L-arginine(100 mg/kg ip), as well as NOS blockade [N(G)-nitro-L-arginine methyl ester(L-NAME)](5 mg/kg ip) given alone and/or combined immediately after celecoxib. Gastrointestinal, liver, and brain lesions and liver enzyme serum values in rats were assessed at 24 h and 48 h thereafter. RESULTS This high-dose celecoxib administration, as a result of NO system dysfunction, led to gastric, liver, and brain lesions and increased liver enzyme serum values. The L-NAME-induced aggravation of the lesions was notable for gastric lesions, while in liver and brain lesions the beneficial effect of L-arginine was blunted. L-arginine counteracted gastric, liver and brain lesions. These findings support the NO system mechanism(s), both NO system agonization(L-arginine) and NO system antagonization(L-NAME), that on the whole are behind all of these COX phenomena. An even more complete antagonization was identified with BPC 157(at both 24 h and 48 h). A beneficial effect was evident on all the increasingly negative effects of celecoxib and L-NAME application and in all the BPC 157 groups(L-arginine + BPC 157; L-NAME + BPC 157; L-NAME + L-arginine + BPC 157). Thus, these findings demonstrated that BPC 157 may equally counteract both COX-2 inhibition(counteracting the noxious effects of celecoxib on all lesions) and additional NOS blockade(equally counteracting the noxious effects of celecoxib + L-NAME). CONCLUSION BPC 157 and L-arginine alleviate gastrointestinal, liver and brain lesions, redressing NSAIDs' post-surgery application and NO system involvement.
基金Supported by Ministry of Science,Education and Sports,Republic of Croatia,No.108-1083570-3635
文摘AIM To cure typically life-threatening esophagogastric anastomosis in rats, lacking anastomosis healing and sphincter function rescue, in particular. METHODS Because we assume esophagogastric fistulas represent a particular NO-system disability, we attempt to identify the benefits of anti-ulcer stable gastric pentadecapeptide BPC 157, which was in trials for ulcerative colitis and currently for multiple sclerosis, in rats with esophagocutaneous fistulas. Previously, BPC 157 therapies have promoted the healing of intestinal anastomosis and fistulas, and esophagitis and gastric lesions, along with rescued sphincter function. Additionally, BPC 157 particularly interacts with the NOsystem. In the 4 d after esophagogastric anastomosis creation, rats received medication(/kg intraperitoneallyonce daily: BPC 157(10 μg, 10 ng), L-NAME(5 mg), or L-arginine(100 mg) alone and/or combined or BPC 157(10 μg, 10 ng) in drinking water). For rats underwent esophagogastric anastomosis, daily assessment included progressive stomach damage(sum of the longest diameters, mm), esophagitis(scored 0-5), weak anastomosis(m L H2 O before leak), low pressure in esophagus at anastomosis and in the pyloric sphincter(cm H2O), progressive weight loss(g) and mortality. Immediate effect assessed blood vessels disappearance(scored 0-5) at the stomach surface immediately after anastomosis creation. RESULTS BPC 157(all regimens) fully counteracted the perilous disease course from the very beginning(i.e., with the BPC 157 bath, blood vessels remained present at the gastric surface after anastomosis creation) and eliminated mortality. Additionally, BPC 157 treatment in combination with L-NAME nullified any effect of L-NAME that otherwise intensified the regular course. Consistently, with worsening(with L-NAME administration) and amelioration(with L-arginine), either L-arginine amelioration prevails(attenuated esophageal and gastric lesions) or they counteract each other(L-NAME + L-arginine); with the addition of BPC 157(L-NAME + L-arginine + BPC 157), there was a marked beneficial effect. BPC 157 treatment for esophagogastric anastomosis, along with NOS-blocker L-NAME and/or NOS substrate L-arginine, demonstrated an innate NO-system disability(as observed with L-arginine effectiveness). BPC 157 distinctively affected corresponding events: worsening(obtained with L-NAME administration that was counteracted); or amelioration(L-arginine + BPC 157-rats correspond to BPC 157-rats).CONCLUSION Innate NO-system disability for esophagogastric anastomoses, including L-NAME-worsening, suggests that these effects could be corrected by L-arginine and almost completely eliminated by BPC 157 therapy.
基金supported by the following grants:National Institute of Environmental Health Sciences funded training program in Environmental Health Sciences (No.T32 ES007058-33) to Jennifer M.Bratt,CTSC K12 Award (No.UL1RR024146)KL2RR024144 to Amir A.Zekithe American Asthma Foundation to Nicholas J.Kenyon.
文摘Exhaled breath nitric oxide (NO) is an accepted asthma biomarker.Lung concentrations of NO and its amino acid precursor,L-arginine,are regulated by the relative expressions of the NO synthase (NOS) and arginase isoforms.Increased expression of arginase I and NOS2 occurs in murine models of allergic asthma and in biopsies of asthmatic airways.Although clinical trials involving the inhibition of NO-producing enzymes have shown mixed results,small molecule arginase inhibitors have shown potential as a therapeutic intervention in animal and cell culture models.Their transition to clinical trials is hampered by concerns regarding their safety and potential toxicity.In this review,we discuss the paradigm of arginase and NOS competition for their substrate L-arginine in the asthmatic airway.We address the functional role of L-arginine in inflammation and the potential role of arginase inhibitors as therapeutics.
文摘A novel poly-l-arginine microcapsule was prepared due to its nutritional function and pharmacological efficacy. A high-voltage electrostatic droplet generator was used to make uniform microcapsules. The results show that the membrane strength and permeating property are both remarkably affected with the changes of sodium alginate concentration. With the sodium alginate concentration increasing, gel beads sizes increase from 233μtm to 350μtm, release ratio is also higher at the same time, but the membrane strength decreases.
基金a grant from the Science & Technology Development Foundation of Guangdong Health Bureau(No.2006345).
文摘BACKGROUND:Although the use of non-heart beating donors(NHBDs)could bridge the widening gap between organ demand and supply,its application to liver transplantation is limited due to the high incidence of primary graft loss.Prevention of liver injury in NHBDs will benefit the results of transplantation.This study was conducted to evaluate the protective effects of L-arginine on liver grafts from NHBDs. METHODS:One hundred and four Wistar rats were randomly divided into 7 groups:normal control(n=8) controls 1,2 and 3(C1,C2,C3,n=16),and experimenta 1,2 and 3(E1,E2,E3,n=16).For groups C1 and E1,C2 and E2,and C3 and E3,the warm ischemia time was 0,30,and 45 minutes,respectively.Liver grafts were flushed with and preserved in 4℃Euro-collins solution containing 1 mmol/L L-arginine for 1 hour in each experimental group Recipients of each experimental group were injected with L-arginine(10 mg/kg body weight)by tail vein 10 minutes before portal vein reperfusion.Donors and recipients of each experimental control group were treated with norma saline.Then transplantation was performed.At 1,3,and 24 hours after portal vein reperfusion,blood samples were obtained to determine the levels of alanine aminotransferase (ALT),aspartate aminotransferase(AST),nitric oxide (NO)and plasma endothelin(ET).At 3 hours after porta vein reperfusion,grafts samples were fixed in 2.5% glutaraldehyde for electron microscopic observation.RESULTS:At 1 hour after portal vein reperfusion,the levels of NO in groups E1,E2,E3 and C1,C2,C3 were lower,while the levels of plasma ET,serum ALT and AST were higher than those in the normal control group(P<0.05).At 1,3,and 24 hours,the levels of NO in groups E1,E2,E3 were higher,while the levels of plasma ET,serum ALT and AST were lower than those in the corresponding control groups(C1,C2,C3) (P<0.05).The levels of NO in groups C2 and C3 were lower than in group C1(P<0.05),and the level of NO in group C3 was lower than in group C2(P<0.05).At 1,3 and 24 hours, the levels of plasma ET,serum ALT,and AST in groups E1, E2,E3 were lower than those in the corresponding control groups(C1,C2,C3)(P<0.05).The levels of plasma ET,serum ALT,and AST were lower in group C3 than in groups C1 and C2(P<0.05).Pathological changes in groups E1,E2,E3 were milder than those in the corresponding experimental control groups(C1,C2,C3). CONCLUSIONS:The imbalance between NO and ET plays an important role in the development of ischemia- reperfusion injury of liver grafts from NHBDs.L-arginine can attenuate injury in liver grafts from NHBDs by improving the balance between NO and ET.
文摘AIM To study the counteraction of perforated cecum lesion using BPC 157 and nitric oxide(NO) system agents.METHODS Alongside with the agents' application(after 1 min, medication(/kg, 10 ml/2 min bath/rat) includes: BPC 157(10 μg), L-NAME(5 mg), L-arginine(100mg) alone or combined, and saline baths(controls)) on the rat perforate cecum injury, we continuously assessed the gross reappearance of the vessels(USB microcamera) quickly propagating toward the defect at the cecum surface, defect contraction, bleeding attenuation, MDA-and NO-levels in cecum tissue at 15 min, and severity of cecum lesions and adhesions at 1 and 7 d. RESULTS Post-injury, during/after a saline bath, the number of vessels was significantly reduced, the defect was slightly narrowed, bleeding was significant and MDA-levels increased and NO-levels decreased. BPC 157 bath: the vessel presentation was markedly increased, the defect was noticeably narrowed, the bleeding time was shortened and MDA-and NO-levels remained normal. L-NAME: reduced vessel presentation but not more than the control, did not change defect and shortened bleeding. L-arginine: exhibited less vessel reduction, did not change the defect and prolonged bleeding. In combination, mutual counteraction occurred(L-NAME + L-arginine) or the presentation was similar to that of BPC 157 rats(BPC 157 + L-NAME; BPC 157 + L-arginine; BPC 157 + L-NAME + L-arginine), except the defect did not change. Thereby at day 1 and 7, saline, L-NAME, L-arginine and L-NAME + L-arginine failed(defect was still open and large adhesions present). CONCLUSION The therapeutic effect was achieved with BPC 157 alone or in combination with L-NAME and L-arginine as it was able to consolidate the stimulating and inhibiting effects of the NO-system towards more effective healing recruiting vessels.
