Adiponectin Inhibits The Apoptosis Of Cardiomyocytes Induced By Endoplasmic Reticulum Stress After Exposed To Tunicamycin Through P38-MAPK

Aim To investigate the protective effects of adiponectin on endoplasmic reticulum stress in jury of the3-4days SD rat cardiomyocytes, which was induced by the tunicamycin and the signaling pathway of its protection.Methods Primary cardiomyocytes were obtained from neonatal rat and cultured by enzymatic digestion methods. The morphology of neonatal rat cardiomyocytes was studied by inverted phase contrast microscope. Its molecular markers were observed by a-actin immunocytochemistry. Primary3-4days cells were used in experiment, and they were randomly divided into control group, tunicamycin group (1mg/L tunicamycin,24h), tunicamycin+100mg/L APN group, tunicamycin+3umol/L SB203580(the inhibitor of p38-MAPK), tunicamycin+3umol/L SB203580+100mg/L APN group. The change of morphology of cardiomyocytes was observed by inverted phase contrast microscope. The cardiomycocytes apoptosis was detected by Annexin V-FITC/PI flow cytometry. The expressions of GRP78and CHOP which were molecular markers of endoplasmic reticulum were detected by qRT-PCR and immunofluorescence technic.Results Compared with the control group, the apoptosis of cardiomyocytes was significantly increased and the molecular makers of endoplasmic reticulum stress GRP78and CHOP were greatly increased after exposed to tunicamycin. Adiponectin pretreatment significantly decreased the apoptosis rate, and the expression of GRP78and CHOP. SB203580pretreatment decreased the protection of adiponectin, the apoptosis was higher compared with tunicamycin+adponectin group and the expression of GRP78and CHOP were increased. Compared to tunicamycin group, the apoptosis was lower and the expression of GRP78and CHOP was decreased.Conclusion tunicamycin enhance the expressions of GRP78and CHOP, and make endoplasmic reticulum stress to start which induces the apoptosis of cardiomyocytes. Adiponectin which can attenuate endoplasmic reticulum stress, have a protective effect on myocardial cells. Its protection against endoplasmic reticulum stress was partly through p38-MAPK signaling pathway.