微小RNA-155在心肌细胞凋亡中的生物学作用探讨

Biological effects of micro RNA-155 in cardiac myocyte apoptosis

目的探讨微小RNA(miR)-155在心肌细胞凋亡过程中的生物学作用.方法采用不同浓度和时相氧化型低密度脂蛋白(ox-LDL)处理小鼠来源的巨噬细胞系RAW264.7细胞,分别转染miR-155 mimics(M组)、miR-155 mimics-NC(M-NC组)、miR-155 inhibitor(I组)及miR-155 inhibitor-NC(I-NC组),CCK-8法检测细胞活性,TUNEL和流式细胞术检测细胞凋亡情况.结果ox-LDL以浓度和时间依赖性方式上调Raw264.7细胞miR-155表达和抑制Raw264.7细胞活力,用不同浓度(10、20、40、80和160 mg/L)ox-LDL和80 mg/L的ox-LDL以不同时相(6、12、24、48和72 h)处理后,Raw264.7细胞miR-155表达呈明显上升,Raw264.7细胞活力呈明显降低,与空白对照比较差异有统计学意义(P<0.05).M组细胞活力明显高于M-NC组,I组细胞活力明显低于I-NC组,差异有统计学意义(P<0.05);与M-NC组比较,M组凋亡细胞明显增加;与I-NC组比较,I组凋亡细胞明显降低,差异有统计学意义(P<0.05).结论miR-155过度表达可以促进ox-LDL诱导的Raw264.7细胞凋亡.

Objective To analyze the biological effects of miRNA-155 in the cardiac myocyte apoptosis. Methods The mouse-derived macrophage cell line RAW264.7 was treated by different concentration or different stage of oxidized low density lipoprotein (ox-LDL), and transfected by miR-155 mimic (M group), miR-155 mimics-NC (M-NC group), miR-155 inhibitor (I group) or miR-155 inhibitor-NC (I-NC group), respectively. The cell viability was measured by CCK-8 assay, cell apopotosis was measured by TUNEL and flow cytometry. Results The ox-LDL induced cell viability of Raw264.7 cells decreased and the expression of miR-155 increased in dose and time dependent manner, after treatment with different concentration of ox-LDL (10, 20, 40, 80, 160 mg/L) or 80 mg/L of ox-LDL with different stage (6, 12, 24, 48, 72 h). The expression of miR-155 increased significantly. Raw264.7 cell viability decreased significantly, compared to that of the blank control. The difference between two groups had statistical significance (P<0.05). The cell viability in M group was significantly higher than that in M-NC group, in I group was significantly higher than that in I-NC group, and the difference between two groups was statistical significance (P<0.05). Compared to that in the M-NC group, the cell apoptosis rate in M group was significantly increased (P<0.05), compared to that in the I-NC group, the cell apoptosis rate in I group were significantly decreased (P<0.05). Conclusions miR-155 can enhance the Raw264.7 cell apoptosis induced by ox-LDL.