α-亚麻酸对糖尿病大鼠血管功能和氧化应激的影响

Effects of alpha-linolenic acid on vascular function and oxidative stress in diabetic rats

目的:观察α-亚麻酸(ALA)对糖尿病(DM)大鼠血管功能和氧化应激的影响,探讨ALA在DM血管并发症防治中的作用。方法:将30只SD大鼠随机分为正常对照组、DM模型组和ALA治疗组[500μg/(kg.d)],每组10只。10只雄性SD大鼠以高脂饮食喂养4周后,腹腔注射链脲佐菌素(STZ)30 mg/kg建立Ⅱ型DM(T2DM)模型。4周后分离降主动脉,进行离体血管灌流观察血管的舒张功能,利用试剂盒测定灌流液中NO的含量以及血管组织中丙二醛(MDA)的含量、超氧化物岐化酶(SOD)和过氧化氢酶(CAT)的活性。结果:与正常对照组相比,DM大鼠主动脉内皮依赖性舒张功能和NO的含量显著下降(P<0.01),ALA治疗可有效地减轻DM大鼠血管内皮功能障碍,增加NO的含量(均P<0.01)。另外,与正常对照组相比,DM大鼠血管组织中MDA的含量增加(P<0.01),抗氧化酶SOD和CAT的活性下降(P<0.01);ALA治疗可显著降低DM大鼠血管组织中MDA的含量(P<0.05),增加抗氧化酶SOD和CAT的活性(P<0.01)。结论:ALA可显著改善T2DM模型大鼠的血管内皮舒张功能障碍,其机制可能与减轻血管组织的氧化应激有关。

AIM：To investigate the effects of alpha-linolenic acid （ALA） on vascular function and oxidative stress in diabetic rats. METHODS： An experimental type 2 diabetes mellitus rat model was induced by feeding male Sprague Dawley （SD） rats a high-fat diet for 4 weeks and injecting streptozocin （STZ） i.p. at 30 mg/kg into the rats. Thirty SD rats were randomized equally into three groups： control group, diabetic group and ALA group. The rats were killed and the descending aorta was isolated 4 weeks later. Vascular function, nitric oxide （NO） production, malondialdehyde （MDA）, superoxide dismutase （SOD） and catalase （CAT） were determined. RESULTS： Significant endothelial dysfunction and decreased NO production were observed in diabetic rats compared with the control group. Treatment with ALA significantly preserved endothelium-dependent vasorelaxation and increased NO production （both P〈0.01 vs. diabetic group）. Furthermore, treatment with ALA reduced MDA production and promoted SOD and CAT activities in the aorta compared with those in the diabetic group. CONCLUSION： These results indicate that an ALA-rich diet preserves endothelium-dependent vasorelaxation in diabetic rats, which may be related to the anti-oxidative effect of ALA.