Role of microRNA-133b-5p in apoptosis induced by hypoxia/reoxygenation in rat cardiomyocytes / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of microRNA-133b-Sp (miR-133b-Sp) in apoptosis hypoxia/reoxygenation (H/R) induced by in rat cardiomyocytes.Methods Rat myocardial cell line H9c2 was cultured in DMEM/F12 culture medium supplemented with 10％ fetal bovine serum.The cells were seeded in 96-well or 6-well plates and randomly divided into 4 groups (n=64 wells each)control group (group C);group H/R;miR-133b-5p mimic + H/R group (group M+H/R);miR-133b-Sp negative control + H/R group (group NC+H/R).The cells were exposed to 95％ N2-5％ CO2for 5 h at 37 ℃ followed by 1 h reoxygenation in DMEM/F12 culture medium supplemented with 10％ fetal bovine serum in all the groups except group C.The cells were cultured in normal culture atmosphere in group C.In M+H/R and NC+H/R groups,the cells were transfected with miR-133b-5p mimic (final concentration 30 nmol/L) and miR-133b-5p negative control (final concentration 30 nmol/L),respectively,for 24 h before H/R.Total RNA was extracted from cells to detect the expression of miR-133b-5p using quantitative real-time PCR.The cell viability (by CCK-8) and lactic dehydrogenase (LDH) activity in the culture medium were detected.Cell apoptosis was assessed by Annexin V/PI flow cytometry.Apoptotic rate was calculated.Result Compared with group C,the cell viability was significantly decreased,and the LDH activity and apoptotic rate were increased in H/R,M+H/R and NC+H/R groups,the expression of miR-133b-5p was down-regulated in H/R and NC+H/R groups,and the expression of miR-133b-Sp was up-regulated in group M+H/R.Compared with group H/R,the cell viability was significanttly increased,the LDH activity and apoptotic rate were decreased,and the expression of miR-133b-5p was up-regulated in group M+H/R,and no significant change was found in the parameters mentioned above in group NC+H/R.Conclusion H/R in rat cardiomyocytes can induce cell apoptosis possibility through down-regulating the expression of miR-133b-5p