miR-499-5p上调对动脉粥样硬化大鼠心肌细胞凋亡的影响及作用机制

目的研究微小核糖核酸(micoroRNA,miR)-499-5p上调对动脉粥样硬化大鼠心肌细胞凋亡影响及作用机制。方法选取30只健康Wistar大鼠,经腹腔注射维生素D3和高脂饲料喂养方法建立动脉粥样硬化模型,分为模型组、竞争性短核糖核苷酸阴性对照序列(scramble-NC)组和miR-499-5p上调组各10只,另选10只健康Wistar大鼠为正常组。构建miR-499-5p表达载体,检测血清氧化应激指标[丙二醛(MDA)、超氧化物歧化酶(SOD)、肌酸激酶(CK)、髓过氧化物酶(MPO)]、炎症因子[白细胞介素(IL)-1β、肿瘤坏死因子(TNF)-α、IL-10]水平。HE染色观察心肌细胞凋亡,Western blot法检测心肌细胞凋亡相关蛋白[B细胞淋巴瘤/白血病-xl(Bcl-xl)和Bcl-2相关X蛋白(Bax)]的表达。结果模型组、scramble-NC组、miR-499-5p上调组较正常组血清CK、MDA、MPO、IL-1β、TNF-α水平和心肌细胞凋亡率、Bax蛋白表达升高,SOD、IL-10水平和Bcl-xl蛋白表达降低(P均<0.05);miR-499-5p上调组较模型组及scramble-NC组血清CK、MDA、MPO、IL-1β、TNF-α水平和心肌细胞凋亡率、Bax蛋白表达降低,SOD、IL-10水平和Bcl-xl蛋白表达升高(P均<0.05)。结论miR-499-5p上调可逆转动脉粥样硬化所致氧化应激、血管炎症反应,抑制大鼠动脉粥样硬化发展,可能通过调控Bax、Bcl-xl蛋白表达,抑制心肌细胞凋亡。

Effect of up regulation of miR-499-5p on cardiomyocyte apoptosis and its mechanism in atherosclerotic rats

Objective To study the effect of up regulation of miR-499-5p on cardiomyocyte apoptosis in atherosclerotic rats and its mechanism.Methods The atherosclerotic models in 30 healthy Wistar rats were established by intraperitoneal injection of Vitamin D3 and high-fat diet,and divided into model group,scramble-NC group,miR-499-5p up-regulated group(n=10,each),another 10 healthy Wistar rats were selected as normal group(n=10).The miR-499-5p expression vector was constructed,and the levels of malondialdehyde(MDA),superoxide dismutase(SOD),creatine kinase(CK),myeloperoxidase(MPO),interleukin(IL)-1β,tumor necrosis factor(TNF)-αand IL-10 were detected.HE staining was used to observe the apoptosis of cardiomyocytes,and Western blot was used to detect the expressions of apoptosis-related proteins[B-cell lymphoma/leukemia xl(Bcl-xl)and Bcl-2-related X protein(Bax)].Results Compared with normal group,the levels of CK,MDA,MPO,IL-1β,TNF-α,cardiomyocyte apoptosis rate and Bax protein expression significantly increased,and the levels of SOD,IL-10 and Bcl-xl protein expression decreased in model group,scramble NC group and miR-499-5p up-regulated group(all P<0.05).In miR-499-5p up-regulated group,the serum levels of CK,MDA,MPO,IL-1β,TNF-α,cardiomyocyte apoptosis rate and Bax protein expression decreased,and the levels of SOD and IL-10 and Bcl-xl protein expression increased compared with those in model group and scramble-NC group(all P<0.05).Conclusion Up regulation of miR-499-5p may reverse oxidative stress and vascular inflammatory response in atherosclerotic rats,so as to inhibit the development of atherosclerosis and may inhibit the apoptosis of cardiomyocytes by regulating Bax and Bcl-xl protein expressions.