The Mechanism Of Cardiomyocyte Apoptosis Induced By Endoplasmic Reticulum Stress After Hypoxia In Rat Myocardial Cells With Hypoglycemia

Objectives To observe the affection of hypoglycemia to ERS protein GRP78/BIP,chemosensory protein PERK, ATF-6 receptor, IRE-1 and the expression of apoptotic signal molecules CHOP, Caspase12, and then to determine the effect, the target for many antibiotics and the signal pathway of apoptosis induced by ERS in the hypoxia model in rat myocardial cells in vitro, which may provide a new direction and a new argument to explore the risk factors of myocardial cell apoptosis under hypoxic condition and reduce its apoptosis rate in the future.Methods By adjusting the concentration of glucose medium to simulate human blood glucose concentration and culturing in hypoxia incubator to form myocardial hypoxia model, we cultured H9C2 cell line of cardiomyocytes(D26-D29) dividing into 4 groups based on the random principle: no hypoxia with normal glucose group(group SN) :18mmol/L glucose medium, normal culture; no hypoxia with hypoglycemia(group SL) :3mmol/L glucose medium, normal culture; hypoxia with normal glucose group(group MN) : 18mmol/L glucose medium, hypoxia culture; hypoxia with hypoglycemia(group ML) : 3mmol/L glucose medium, hypoxia culture. By the observation of the process of ERS developed and the characteristics of the signal transduction pathways, we want to observe the expression of ERS protein GRP78/BIP, chemosensory protein PERK, ATF-6receptor, IRE-1 and the expression of apoptotic signal molecules CHOP, Caspase12 by using Western Blot and Real-time PCR detection. We want to explore the changing law of ERS in the process of myocardial cell apoptosis after hypoxia and reveal the mechanisms and pathways of the hypoglycemia aggravating myocardial cell apoptosis mediated by ERS.Results 1 Compared with group SN, group SL had higher protein expression of GRP78/BIP, PERK, PERK, ATF-6, IRE-1, CHOP and Caspase-12, which has statistical significance(P<0.05); 2 The expression of GRP78/BIP, PERK, ATF-6, IRE-1, CHOP and Caspase-12 protein in MN group were higher than that in SN group, and the difference has statistical significance(P<0.05); 3 The expression of GRP78/BIP, PERK,ATF-6, IRE-1, CHOP and Caspase-12 protein in group ML were higher than that in group MN, and the difference has statistical significance(P<0.05); 4 In gene expression,compared with group MN, the expression of GRP78/BIP m RNA, PERK m RNA, ATF-6m RNA, IRE-1 m RNA, CHOP m RNA and Caspase12 m RNA in group ML were higher,the difference has statistical significance(P< 0.05), which is consistent with the trend of the expression of above 6 protein of the commensurate group.Conclusion Through the establishment of hypoxia model of H9C2 rat myocardial cells,this study approved that endoplasmic reticulum stress and apoptosis pathway induced by myocardial cell after hypoxia; and hypoglycemia increased the apoptosis of myocardial cells after hypoxia, and its mechanism may be that hypoglycemia through 3 pathways contributing to the occurrence and development of apoptosis of hypoxic myocardial cells induced by endoplasmic reticulum stress mediated by PERK, IRE-1, ATF-6.