异丙肾性心肌梗死大鼠钙敏感受体的表达和凋亡通路的变化

Change of calcium sensing receptor expression and apoptotic pathways in myocardial infarction rat induced by isoprel

目的:观察钙敏感受体(CaSR)在异丙肾性心肌梗死大鼠的表达和凋亡通路的变化。方法:采用连续2 d大剂量异丙肾上腺素(200 mg/kg)皮下注射制备大鼠心肌梗死模型。Wistar大鼠随机分为3组:正常对照组(control);异丙肾上腺素1 d组(ISO/1d);异丙肾上腺素2 d组(ISO/2d)。采用RT-PCR和Western blotting分别观察CaSR、bax、bcl-2、caspase-3 mRNA和蛋白表达;TUNEL染色观察心肌细胞凋亡情况;光镜和电镜分别观察心肌形态学和超微结构变化;紫外分光法检测乳酸脱氢酶(LDH)、肌酸激酶(CK)、超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量,电化学免疫发光法检测肌钙蛋白(cTnT)水平。结果:与正常组比较,ISO/1d组:LDH和CK活性、cTnT水平和MDA含量、细胞凋亡指数以及CaSR、Bax和caspase-3的表达均达高峰,同时SOD活性降低,Bcl-2表达减少,心肌细胞超微结构损伤严重;ISO/2d的心肌损伤指标较ISO/1d组有所减轻。结论:CaSR表达增多可能参与了异丙肾性大鼠心肌梗死的发生,其机制与氧化应激和细胞凋亡有关。

AIM： To observe the change of calcium sensing receptor （CaSR） expression and apeptotic pathways in myocardial infarction rat induced by isoprel. METHODS： The myocardial infarction rat models were prepared by subcutaneous injection of isoprel （ ISO 200 mg· kg^-1 · d^-1 for 2 d）. Wistar rats were divided into three groups randomly： （2） Control group; （2） ISO/ld group; （3） ISO/2d group. The expressions of CaSR, bcl-2, bax and caspase -3 mRNA and protein were analyzed by RT - PCR and Western blotting, respectively. Apoptotic cells were measured by TUNEL staining assay. The morphological and uhrastructural changes were observed under optical microscope and electronic microscope. The activity of LDH, CK, SOD and the content of MDA were assayed with ultraviolet spectrophotometer. The level of tropenin（cTnT） was observed by chemical immunofluoresence. RESULTS： Compared with control group, the activity of LDH and CK, the content of MDA and cTnT, the apoptosis index and the expression of CaSR, Bax and caspase - 3 were reached the highest level, but the SOD activity and Bcl -2 expression were decreased. The myocardial ultrastructural injury was aggravated in the ISO/1d group. The change of above parameters in ISO/2d group was between control and ISO/1d group. CONCLUSION： The increased expression of CaSR is involved in rat myocardial infarction induced by isoprel, which is related with oxidative stress and apoptosis.