摘要
目的 探讨NG-硝基-L-精氨酸（L-NA）对内毒素性肺损伤大鼠肺表面活性物质（PS）和细胞凋亡的影响.方法 雄性SD大鼠24只,按随机数字表法均分为对照组、模型组、L-NA治疗组.模型组、L-NA治疗组舌下静脉注射脂多糖（LPS）复制内毒素性肺损伤模型;对照组给予等量生理盐水.L-NA治疗组于注射LPS 3 h后给予L-NA 20 mg/kg;对照组和模型组给予等量生理盐水.6 h后处死动物,取肺组织,用原位杂交法测定肺组织表面活性物质相关蛋白A（SP-A）mRNA表达;用流式细胞术检测肺组织细胞凋亡率;用蛋白质免疫印迹法（Western blotting）检测天冬氨酸特异性半胱氨酸蛋白酶3（caspase-3）蛋白表达;用免疫组化法测定Bcl-2和Bax蛋白表达.结果 与对照组比较,模型组SP-A mRNA表达[吸光度（A）值]明显下降（0.071±0.017比0.113±0.021）,细胞凋亡率[（25.04±4.57）%比（11.37±3.08）%]、caspase-3蛋白表达（A值：298.64±37.11比110.24±14.35）、Bax蛋白表达（A值：0.145±0.011比0.076±0.010）明显升高,Bcl-2蛋白表达（A值：0.064±0.011比0.073±0.009）和Bcl-2/Bax比值（0.447±0.086比0.976±0.157）明显下降（均P〈0.01）.与模型组比较,L-NA治疗组SP-A mRNA表达（A值：0.085±0.015）和Bcl-2蛋白表达（A值：0.070±0.087）明显增强（P〈0.01和P〈0.05）,但细胞凋亡率[（20.67±1.35）%]、caspase-3蛋白表达（A值：268.75±42.56）、Bax蛋白表达（A值：0.142±0.012）和Bcl-2/Bax比值（0.498±0.069）均无明显变化（均P〉0.05）.结论 L-NA不通过抑制肺细胞凋亡来减轻内毒素性肺损伤的程度,对调节凋亡相关基因caspase-3和Bax也无明显影响;而是可通过增强PS表达减轻内毒素性肺损伤.
Objective To investigate the effects of NG-nitro-L-arginine （L-NA） on pulmonary surfactant （PS） and pulmonary cells apoptosis in lipopolysaccharide （LPS） induced acute lung injury （ALI）. Methods Twenty-four male Sprague-Dawley （SD） rats were randomly divided into three groups： control group, model group, L-NA group. Model of ALI was reproduced by injection of LPS 5 mg/kg via sublingual vein in model group and L-NA group. L-NA （20 mg/kg） was administered in L-NA group, while normal saline was administered in control group and model group 3 hours after LPS injection. The rats were sacrificed at 6 hours after LPS injection, and the lung tissue was obtained for measuring the expressions of pulmonary surfactant protein A （SP-A） mRNA by in situ hybridization （ISH） method; meanwhile, apoptosis rate was evaluated by flow cytometry; the expression of caspase-3 was evaluated by Western blotting analysis; Bcl-2 and Bax were evaluated respectively by immunohistochemisty （IHC）. Results Compared with that of the control group, SP-A mRNA [absorbance （A） value] in the lung tissue was significantly decreased by LPS （0.071±0.017 vs. 0.113±0.021） in model group, apoptosis rate of pulmonary cells [（25.04±4.57）% vs. （11.37±3.08）%], caspase-3 protein expression （A value： 298.64±37.11 vs. 110.24±14.35） and Bax protein expression （A value： 0.145±0.011 vs. 0.076±0.010） were significantly increased, Bcl-2 protein expression （A value： 0.064±0.011 vs. 0.073±0.009） and Bcl-2/Bax （0.447±0.086 vs. 0.976±0.157） were decreased in model group （all P〈0.01）. L-NA was given at 3 hours after LPS administration, the expressions of SP-A mRNA （A value： 0.085±0.015） and Bcl-2 protein （A value： 0.070±0.087） increased markedly, compared with model group （P〈0.01 and P〈0.05）, but there were no significant changes in the pulmonary cells apoptosis rate [（20.67±1.35）%], caspase-3 protein expression （A value： 268.75±42.56）, Bax protein expression （A value： 0.142±0.012） and Bcl-2/Bax （0.498±0.069） between L-NA group and model group （all P〉0.05）. Conclusion L-NA had no effect on LPS-induced pulmonary cell apoptosis and had no effect on the expressions of caspase-3 and Bax, but L-NA can protect the lung from LPS-induced injury by up-regulating the expression of PS.
出处
《中国危重病急救医学》
CAS
CSCD
北大核心
2010年第7期397-400,共4页
Chinese Critical Care Medicine
基金
国家人事部留学人员重点资助项目（9900789）
河北省博士基金资助项目（99547015D）
河北省卫生厅科研基金项目（20090040）
