摘要
目的观察不同病程(5、10周)的糖尿病(DM)大鼠氧化应激和血红素氧化酶(heme oxygenase,HO)-1系统的动态变化,探讨HO-1在DM血管病变发展进程中的作用,同时探讨天然抗氧化剂罗汉果皂苷(MG)对DM大鼠的血管保护作用及机制。方法雄性SD大鼠注射链脲佐菌素诱导DM模型。将实验大鼠分为正常对照组(C组)、正常+MG提取物组(C+MG组)、DM组(D组)和DM+MG提取物组(D+MG组),每组均为20只。C组和D组接受0.9%氯化钠溶液灌胃,C+MG组和D+MG组以罗汉果皂苷提取物150mg/kg灌胃。实验过程中每周监测体重,灌胃5、10周后分别检测血糖、血清中游离脂肪酸(FFA)含量以及血清总抗氧化能力(TAOC)和丙二醛(MDA)水平。取各组胸主动脉行常规病理学检查,应用免疫组织化学法检测肿瘤坏死因子(TNF)-α在各组血管组织的表达,应用逆转录-聚合酶链反应(RT-PCR)和Western印迹法检测HO-1mRNA和蛋白的表达,电子显微镜下观察血管内皮超微结构的改变。结果①与C组、C+MG组比较,D组、D+MG组各观察时间点的饮水量均显著增加(P值均<0.05),体重均显著减轻(P值均<0.05);从第3周起,D+MG组的饮水量显著少于D组(P<0.05);1周后,D+MG组的体重显著大于D组(P<0.05)。②D组、D+MG组5、10周的血糖均显著高于C组、C+MG组(P值均<0.05),D+MG组血糖显著低于D组(P<0.05);病程5周时,D组与C组间血清FFA的差异无统计学意义(P>0.05),10周时D组的血清FFA含量显著低于D+MG组(P<0.05)。③5、10周时,D组TAOC均显著低于C组(P值均<0.05),D+MG组显著高于D组(P值均<0.05);D组MDA水平显著高于C组(P值均<0.05),D+MG组显著低于D组(P值均<0.05)。④5周时,D组大鼠血管HO-1mRNA和蛋白水平均显著高于C组(P值均<0.05),D+MG组显著低于D组(P值均<0.05);10周时,D组大鼠血管HO-1mRNA和蛋白水平均显著低于C组(P值均<0.05),D+MG组显著高于D组(P值均<0.05)。⑤5周时D+MG组线粒体肿胀情况较D组减轻,所取标本也未见明显上皮脱落情况;10周时内皮损伤情况较5周时重,但较D组减轻,也未发现细胞核明显固缩、溶解破坏的情况。结论氧化应激在不同的时期通过影响(诱导或抑制)抗氧化应激蛋白HO-1系统参与DM血管病变的发生、发展过程。MG可以降糖、降FFA,并减轻DM发展进程中的氧化应激反应,保护血管内皮。其抗氧化作用的发挥可能由HO-1介导。
Objective To observe the heme oxygenase-1（HO-1） expression changes in rats with 5- and 10-week diabetes （DM） in the absence and presence of a natural antioxidant Momordica grosvenori （MG）, and to assess the protective effect of MG on the blood vessels of DM rats. Methods Male Sprague-Dawley （SD） rats were made into diabetic model by a single intra-peritoneal injection of STZ （50 mg/kg）. The rats were divided into normal control group （group C）, normal control ＋ MG （C-MG group）, diabetic group （group D） and diabetes ＋ MG group （D-MC group） （ n = 20）. Control （n = 40） and diabetic rats （n=40） were treated with saline or MG （150 mg/kg 7 day） via gavage for 5 or 10 weeks. The body weight and blood glucose were determined on a weekly basis. Serum FFA, total antioxidant capacities （TAOC） and malondialdehyde （MDA） contents were measured. Vascular expression and distribution of tumor necrosis factor-α （TNF-α） were examined and observed by immunohsitochemistry in the thoracic aorta. HO-1 mRNA and protein expressions of vascular tissue were detected by RT-PCR and Western blotting assay. The ultrastructure of thoracic aorta was observed under the light microscope and transmission electron microscope. Results ① MG significantly attenuated the hyperglycemia, polydipsia and increased body weights of diabetic rats from the 3th week （P〈0.05）. ② FAA remained unchanged at 5 weeks post STZ injection and significantly increased at 10 weeks post STZ injection, which was significantly reduced by MG （P〈0.05）. ③ Serum TAOC was decreased in a time-dependent manner and the content of MDA was progressively increased in diabetic rats and these effects were partially reversed by MG （ P〈0.05）.④The mRNA and protein expressions of HO-1 in the thoracic aorta of diabetic rats were significantly enhanced at 5th week and decreased at 10th week （P〈0.05）; these changes were significantly attenuated by MG （P〈0.05）.⑤ Imrnunohistochemical results demonstrated that MG significantly attenuated the increased TNF-a positive cells in aorta. Conclusion HO-1 is involved in the oxidative stress responses in DM rats. MG can attenuate vascular oxidative stress and angiopathies in DM rats through its anti-oxidative action by modulating HO-I. （Shanghai Med J, 2009, 32： 400-405）
出处
《上海医学》
CAS
CSCD
北大核心
2009年第5期400-405,I0001,共7页
Shanghai Medical Journal
关键词
罗汉果皂苷
2型糖尿病
氧化应激
Momordica grosvenori
Type 2 diabetes mellitus
Oxidative stress
