Objective To observe the impact of diabetes and oxidative stress on endothelial dysfunction of carotid atherosclerosis ( CAS) rats.Methods From June to October in 2014, 30 healthy male SPF-grade Wistar rats were divided into control group, CAS group and diabetic CAS group with 10 rats in each group by random table method.CAS group and diabetic CAS group were given intraperitoneal injection of a single dose of Vitamin D3 by 600, 000 U per kg body weight with high-fat diet.In the fifth week, diabetic CAS group was given intraperitoneal injection of a dose of Streptozocin by 45 mg per kg body weight.Control group was fed with basic diet.After 15 weeks, the rats were sacrificed, and 3 mm fresh carotid arterial ring was sectioned from each of the separated carotid arteries.The carotid artery ring tension was measured by adding different concentrations of acetylcholine (10-9 , 10 -8 , 10-7 , 10-6 , 10-5 and 10 -4 mol/L) into HV-4 out body tissue organ constant temperature perfusion system.Carotid artery tissue was observed by Hematoxylin and Eosin staining, and the average optical density of CyPA, KLF2 and eNOS was measured by immunohistochemistry SP method.Results After the addition of different concentrations of acetylcholine into HV-4 out body tissue organ constant temperature perfusion system, the carotid arterial rings of all the three groups had relaxant responses.CAS group and diabetic CAS group were lower than control group in carotid arterial ring tension when acetylcholine was given by 10 -9 , 10-8 , 10 -7 , 10 -6 , 10 -5 and 10-4 mol/L ( P <0.05 ) .Diabetic CAS group was lower than CAS group in carotid arterial ring tension when acetylcholine was given by 10-8 , 10-7 , 10-6 , 10 -5 and 10-4 mol/L ( P <0.05 ) .HE staining showed that carotid artery intima of control group was complete and smooth with endothelial cells and smooth muscle cells in alignment, elastic fibers continuous without breakoff, and no hyperplasia.In CAS group and diabetic CAS group, intima breakage, formation of medial calcification plaques and loss of elastic layer continuity were observed.CAS group and diabetic CAS group were higher in the average optical density of CyPA and lower in the average optical density of KLF2 and eNOS than control group (P<0.05) .Diabetic CAS group was higher in the average optical density of CyPA and lower in the average optical density of KLF2 than CAS group ( P <0.05 ) .Conclusion Diabetes and oxidative stress participate in the formation of endothelial dysfunction of CAS rats, and the mechanism may be related with the increase of CyPA expression.%目的：探讨糖尿病与氧化应激在颈动脉粥样硬化（ CAS）大鼠内皮功能障碍中的作用。方法2014年6—10月选取SPF级健康雄性Wistar大鼠30只，采用随机数字表法分为对照组、 CAS组、糖尿病CAS组，每组10只。CAS组、糖尿病CAS组大鼠给予高脂饲料喂养结合维生素D3注射液60万U／kg一次性腹腔注射建立CAS模型。糖尿病CAS组大鼠第5周时给予链脲佐菌素（ STZ）45 mg／kg腹腔注射建立糖尿病模型。对照组大鼠给予基础饲料喂养结合0.9％氯化钠溶液腹腔注射。15周后处死大鼠，分离颈动脉，截取约3 mm新鲜颈动脉环， HV－4离体组织器官恒温灌流系统中加入不同浓度（10－9、10－8、10－7、10－6、10－5、10－4 mol／L）乙酰胆碱，记录颈动脉环张力（最大舒张度）。苏木素－伊红（ HE）染色观察颈动脉组织，免疫组织化学SP法染色并检测颈动脉亲环素A （ CyPA）、 Kruppel样转录因子2（KLF2）、内皮型一氧化氮合酶（eNOS）平均光密度。结果 HV－4离体组织器官恒温灌流系统中加入不同浓度乙酰胆碱后各组大鼠颈动脉环均出现舒张反应。 CAS组、糖尿病CAS组大鼠10－9、10－8、10－7、10－6、10－5、10－4mol／L乙酰胆碱颈动脉环张力较对照组降低（P＜0.05）；糖尿病CAS组大鼠10－8、10－7、10－6、10－5、10－4 mol／L乙酰胆碱颈动脉环张力较CAS组降低（ P＜0.05）。 HE染色示对照组大鼠颈动脉内膜完整光滑，内皮细胞以及平滑肌细胞排列整齐，无增生；弹性纤维连续无中断。 CAS组、糖尿病CAS组大鼠颈动脉可见内膜断裂，中层钙化斑块形成，弹性层失去连续性。 CAS组、糖尿病CAS组大鼠颈动脉CyPA平均光密度较对照组升高， KLF2、 eNOS平均光密度较对照组降低（ P＜0.05）；糖尿病CAS组大鼠颈动脉CyPA平均光密度较CAS组升高， KLF2平均光密度较CAS组降低（ P＜0.05）。结论糖尿病与氧化应激参与了CAS大鼠内皮功能功能障碍的形成，其机制可能与CyPA表达水平增加有关。
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