Effects Of Nutrient Deprivation On Autophagy Of Different Types Of Cells In The Heart

Objective:To investigate the differences in the survival ability and autophagy level of cardiomyocytes,cardiac fibroblast cells,vascular smooth muscle cells and endothelial cells during nutrient deprivation,as well as the effect of extend the duration of autophagy activation in cardiomyocytes on the survival.Methods:We employed a primary cell culture from neonatal ICR mouse hearts which was consisted of cardiomyocytes,cardiac fibroblast cells,vascular smooth muscle cells and endothelial cells,and investigated how these cells responded to HBSS-induced nutrient deprivation caused by detecting the dynamic change of cell survival and cellular expression of microtubule-associated protein 1 light chain 3(LC3)by immunofluorescent staining in each cell type.To verify the important reason for their decreased survival is caused by rapid disappearance of autophagy activation ability of cardiomyocytes,we treated cardiomyocytes with rapamycin,an autophagy agonist,and analyzed the effects of rapamycin on the duration of autophagy activation and survival of cardiomyocytes.Results:1.The loss of cardiomyocytes in response to nutrient deprivation is significantly,by contrast,the survival of cardiac fibroblast cells,vascular smooth muscle cells and endothelial cells was not altered.2.The expression of LC3 in cardiomyocytes rapidly up-and-down,while the LC3 expression in cardiac fibroblast cells,vascular smooth muscle cells and endothelial cells was largely maintained at high level throughout nutrient deprivation.3.Rapamycin extend the duration of autophagy activation in cardiomyocytes under nutrient deprivation.4.The survival of cardiomyocytes under nutrient deprivation was improved by rapamycin.Conclusion:1.Cardiomyocyte is more sensitive than cardiac fibroblast cells,vascular smooth muscle cells and endothelial cells to nutrient deprivation.2.Nutrient deprivation-induced cell death in cardiomyocytes is associated with a rapid decrease in its autophagy activation.3.Prolonging the duration of autophagy activation of cardiomyocytes can alleviate cardiomyocytes death.