Abstract: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)-α and 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.