厄贝沙坦对糖尿病大鼠心肌内皮细胞转分化的作用

Role of Irbesartan on cardiac endothelial-to-mesenchymal transition in diabetic rats

目的 探讨厄贝沙坦对糖尿病大鼠心肌内皮细胞转分化（EndMT）的影响.方法 体内实验：采用腹腔注射链脲佐菌素（STZ）的方法制备自发性高血压症大鼠（SHR）糖尿病模型（n=8）.模型组大鼠分为糖尿病组和厄贝沙坦（Isb）治疗组;Wistar-Kyoto （WKY）大鼠作为对照组.体外实验：人主动脉内皮细胞（HAEC）被分为对照组（NG,5.5 mmol/L）;高糖组（HG,30 mmol/L糖）;厄贝沙坦组（HG＋Irb,HG＋Irb 1 μmol/L）3组.光镜下观察各组大鼠心肌组织病理学改变;透射电镜观察心肌微血管内皮细胞病理改变.激光扫描共聚焦显微镜（LSCM）免疫荧光染色方法观察心肌和高糖刺激的人主动脉内皮细胞CD31和成纤维细胞特异蛋白1（FSP1）的表达.放射免疫法检测HAEC上清液中血管紧张素Ⅱ的浓度.Western印迹法检测FSP1、α平滑肌肌动蛋白（α-SMA）的表达.结果 与WKY组比较,糖尿病组大鼠出现明显的心肌纤维化.透射电镜结果显示：糖尿病组大鼠心肌微血管内皮指状突起增多.LSCM结果显示心肌CD31和FSP1共表达.体外实验结果显示：与对照组相比,高糖组HAEC细胞上清液中血管紧张素Ⅱ的浓度增加（P＜0.05）,LSCM可见CD31和FSP1表达重叠,部分细胞获得纺锤样改变并失去CD31染色.高糖组FSP1和α-SMA蛋白水平的表达明显增加（均P＜ 0.05）,厄贝沙坦组细胞上述改变减轻（P＜0.05）.结论 厄贝沙坦可通过抑制心肌EndMT,减轻糖尿病心肌纤维化.

Objective To explore the effect of irbesartan on cardiac endothelial-mesenchymal transition （EndMT） in diabetic rats.Methods The model of diabetic rat was induced by intraperitoneal injection with streptozotocin （STZ,35 mg/kg） in spontaneous hypertensive rats （SHR）.Diabetic rats were divided into diabetic group and the Irbesartan treated group.The pathological changes were investigated by fluorescence microscope and electron microscope.The EndMT was studied in human aortic endothelial cells （HAEC） exposure to high glucose.The concentration of angiotensin Ⅱ in the supernatant was detected by radioimmunoassay.Immunofluorescence staining was performed to detect the co-localization of CD31 and FSP1.Results The significant myocardial fibrosis was presented in the diabetic group.Endothelial protrusions were prominent feature in myocardial microvascular of diabetic rat compared with the control group rats.Double staining of HAEC showed co-localization of CD31 and FSP1,which was decreased by the treatment of Irbesartan （P 〈 0.05）.When HAEC was exposed to high glucose,it showed some cells acquired spindle-shaped morphology and lost CD31 staining,and FSP1 and α-SMA protein expression levels were markedly upregulated,which attenuated by the treatment of Irbesartan.Conclusion Irbesartan might prevent diabetes from myocardial fibrosis via inhibition of EndMT in diabetic rats.