中文摘要：

目的：研究微小RNA-34a（microRNA-34a,miR-34a）在阿霉素诱导的心肌细胞凋亡中的作用及其作用靶基因.方法：建立阿霉素（doxorubicin,Dox）诱导的大鼠H9c2心肌细胞凋亡模型;TUNEL染色观察H9c2细胞凋亡;双萤光素酶报告实验检测miR-34a与潜在靶基因沉默信息调节因子1（silent information regulator 1,SIRT1）3＇端非翻译区（3＇-untranslated region,3＇UTR）的结合作用;实时荧光定量PCR检测miR-34a和SIRT1 mR-NA表达水平,Western blot检测SIRT1和凋亡相关蛋白表达水平.结果：阿霉素处理H9c2细胞之后,细胞发生凋亡,miR-34a的表达显著增强;双萤光素酶报告实验提示miR-34a与SIRT13＇UTR可相互作用,并证实miR-34a可在转录后水平抑制SIRT1的表达,SIRT1蛋白水平在阿霉素处理的心肌细胞中显著下调;过表达miR-34a及沉默SIRT1均能一致性抑制Bcl-2表达,促进Bax和p66shc的表达,而过表达SIRT1能有效抑制阿霉素诱导的H9c2细胞凋亡.结论：SIRT1是miR-34a的靶基因,并介导了miR-34a在阿霉素诱导的心肌细胞凋亡中的作用.

英文摘要：

AIM：To investigate the role of microRNA-34a （miR-34a） in doxorubicin （Dox）-induced cardio-myocyte apoptosis and the potential target gene .METHODS：The apoptotic model of H9c2 cells was established by Dox induction.The apoptotic H9c2 cells was detected by TUNEL assay .Dual luciferase reporter assay was performed to confirm the interaction between miR-34a and the 3＇UTR of silent information regulator 1 （SIRT1）.The expression of miR-34a and SIRT1 mRNA was determined by RT-qPCR, and the protein expression of SIRT 1 and apoptosis-related proteins was detec-ted by Western blot .RESULTS： Cell apoptosis and miR-34a was markedly increased in Dox-induced H9c2 cells.Dual luciferase reporter assay revealed that miR-34a interacted with the 3＇UTR of SIRT1, and miR-34a was observed to inhibit SIRT1 expression at the post-transcriptional level .The protein expression of SIRT 1 was markedly decreased in the apoptotic H9c2 cells.Moreover, miR-34a mimic, in parallel to SIRT1 siRNA, inhibited Bcl-2 expression but increased the expression of Bax and p66shc.Overexpression of SIRT1 significantly inhibited Dox-induced apoptosis in the H9c2 cells.CONCLU-SION：SIRT1 is a target gene of miR-34a, and mediates the effect of miR-34a on Dox-induced cardiomyocyte apoptosis .