依那普利对2型糖尿病大鼠肠系膜血管内皮细胞的保护作用

目的　糖尿病血管病变的初始原因是血管内皮细胞损害。本研究观察依那普利对糖尿病大鼠肠系膜血管内皮细胞是否有保护作用。方法　大鼠用高脂饮食饲养 4周后 ,ip链佐霉素 30mg·kg- 1诱导 2型糖尿病 ,继续饲以高脂饮食 4周后 ,依那普利组给予依那普利 10mg·kg- 1·d- 1,ig ,连续 4周。采用大鼠离体肠系膜血管灌流技术 ,用去甲肾上腺素 1μmol·L- 1预收缩血管 ,再给予乙酰胆碱 (ACh) 1μmol·L- 1使血管舒张。观察ACh的舒张率来反映内皮细胞功能。结果　糖尿病大鼠肠系膜血管ACh舒张率为 (33±8) % ,较对照组 (79± 8) %明显降低 ,依那普利治疗组血管ACh舒张率为 (5 2± 6 ) % ,较糖尿病组明显改善。用皂素去内皮后 ,三个组肠系膜血管对ACh舒血管的反应性均明显降低 ,三组间无显著性差异。去内皮前后 ,三个组肠系膜血管对硝普钠舒张血管的反应性无显著变化。结论　依那普利对 2型糖尿病大鼠肠系膜血管内皮细胞具有保护作用。

Protective effect of enalapril on endothelial cells of the mesenteric vascular bed in type 2 diabetic rats

AIM Because the endothelial cells of arteries play a causative role in microvascular complications of type 2 diabetes, the a im of this study is to observe whether enalapril has the protective effect on endothelial cells of the mesenteric vascular bed in type 2 diabetic rats. METHODS Male Sprague-Dawley rats were fed with high sucrose and fat diets. Four weeks later, streptozotocin　(30 mg·kg^-1) was injected ip to induce type 2 diabetes. Another 4 weeks later, enalapril (10 mg·kg^-1·d^-1) was given ig for 4 weeks. The technique of constant- flow perfusion of isolated mesenteric vascular bed was adopted. The mesenteric vascular bed was precontracted by norepinephrine (1 μmol·L^-1), then the endothelium-dependent relaxation to acetylcholine (ACh, 1 μmol·L^-1) were tested to evaluate the function of endothelial cells of the mesenteric vascular bed. RESULTS The endothelium-dependent relaxation of mesenteric vascular bed to ACh in diabetes model group (33±8)% was significantly less than normal control group (79±8)%, while the relaxation of enalapril-treated group (52±6)% was significantly higher than diabetes model group. After removed endothelial cells with saponin (1 μmol·L^-1), the endothelium-dependent relaxations of mesenteric vascular bed to ACh in three groups were significantly decreased, and there was no difference in three groups. Moreover, the relaxations of mesenteric vascular bed to sodium nitroprusside had no difference in three groups before and after removing endothelia cells. CONCLUSION Treatment with enalapril may protect the endothelial cells of mesenteric vascular bed in type 2 diabetic rats.