Moderate Hypothermia Enhances SUMOylation In Cardiomyocytes And Antagonizes H/R-induced Apoptosis

Objectives Observe the effect of low temperature on myocardial cell viability after H/R injury.The effect of low temperature on the level of SUMO in myocardial cells after H/R injury was examined.3 To explore the effect of changes in SUMO levels on cardiomyocyte apoptosis.Methods The H/R model induced by CoCl2 and complete medium was constructed.H9c2 and HL-1 cells were cultured in a low temperature incubator at 33 ? to simulate hypothermia.The experiment was divided into control group,H/R group and hypothermia treatment group.CCK8 was used for detection.Cardiomyocyte activity of cardiomyocytes in three different situations.Flow cytometry was used to detect ROS,and JC-1 fluorescence was observed by confocal microscopy to evaluate mitochondrial function changes.Western Blotting was used to detect the expression levels of SUMO1 and SUMO2/3 in the cardiomyocytes of each group,and detecting the expression levels of apoptosis-related proteins Bcl-2 and caspase-3.SUMO1 interference plasmid siRNA(si-SUMO1)was transfected into H9c2 and HL-1 cardiomyocytes.The experiment was divided into control group,H/R group,hypothermia treatment group and si-SUMO1 group.The cardiomyocyte activity was evaluated again by the above method.,apoptosis,mitochondrial function.Results CCK8 results showed that compared with the normal control group,the activity of cardiomyocytes in the H/R group was significantly decreased.However,the cell viability of the hypothermia group was improved compared with the H/R group.Flow cytometry detection of ROS and confocal microscopy showed that compared with the normal control group,the ROS production in the H/R group was significantly increased,and the mitochondrial membrane potential was significantly decreased.The ROS production in the hypothermia treatment group significantly decreased the mitochondrial membrane potential.Significantly elevated.The results of three Western blots showed that the expression level of SUMO1 protein was decreased in the H/R group compared with the control group,but the expression level of SUMO1 protein in the hypothermia treatment group was significantly higher than that in the H/R group.At the same time,we examined the expression level of SUMO2/3 in different groups,but compared with the expression level of SUMO1 protein,the expression level of SUMO2/3 did not change significantly.Flow cytometry,Western Blotting and confocal microscopy showed that BCL-2 expression and mitochondrial membrane potential were significantly increased,while caspase 3 and mitochondrial ROS levels were significantly decreased.When SUMO1 was knocked down,mitochondrial ROS level significantly increased and mitochondrial membrane potential significantly decreased.Thus,the protective effect of hypothermia on cardiomyocytes was reversed.Conclusions Moderate hypothermia can enhance the expression of SUMO1 in cardiomyocytes and antagonize the apoptosis of cardiomyocytes.Figure[5];Table[2];Reference [129].