miR‐26a调控CTGF表达在放射性心脏损伤中作用的实验研究

目的 探讨miR‐26a在实验鼠放射性心脏损伤（RIHD）中的调节作用。方法 以C57/BL6小鼠构建RIHD模型,检测心功能、纤维化、胶原蛋白1（COL1）、结缔组织生长因子（CTGF）及miR‐26a的表达。双荧光素酶试剂盒检测CTGF是否是miR‐26a的靶基因。在心肌成纤维细胞转染miR‐26a up及miR‐26a down慢病毒,构建miR‐26a过表达和低表达细胞模型,检测心肌成纤维细胞的增殖、凋亡及CTGF的表达。结果 小鼠心脏被辐射后心功能下降、心肌纤维化重塑,COL1和CTGF表达增加,miR‐26a表达下降。双荧光素酶报告基因检测证实CTGF是miR‐26a的靶基因。过表达miR‐26a可抑制心肌成纤维细胞CTGF表达,抑制心肌成纤维细胞增殖,促进凋亡,分泌胶原蛋白;低表达miR‐26a则得到相反的实验结果。结论 miR26a可能通过靶向调控CTGF的表达,影响心肌成纤维细胞的功能,参与放射性心肌纤维化的过程,有望成为RIHD新的治疗靶点。

Experimental study of miR‐26a regulating CTGF expression in radiation‐induced heart disease

Objective To investigate the regulatory effect of miR‐26a in radiation‐induced heart disease (RIHD) mice. Methods C57/BL6 mice were used to establish RIHD models. The cardiac function, fibrosis, the expression levels of collagen 1 (COL1) and connective tissue growth factor (CTGF), and miR‐26a were detected in RIHD mice. Whether CTGF was the target gene of miR‐26a was verified by dual luciferase kit. Moreover, cardiac fibroblasts were transfected with miR‐26a up and miR‐26a down lentivirus vectors to construct the miR‐26a overexpression and underexpression cell models. The expression of CTGF, proliferation, and apoptosis of cardiac fibroblasts were detected. Results In the RIHD mice, heart function was decreased, myocardial fibrosis was remodeled, the expression levels of COL1 and CTGF were up‐regulated, and the expression level of miR‐26a was down‐regulated. Dual luciferase reporter assay confirmed that CTGF was the target gene regulated by miR‐26a. Overexpression of miR‐26a could inhibit the expression of CTGF, suppress the proliferation of cardiac fibroblasts, promote cell apoptosis and secrete collagen. Underexpression of miR‐26a yielded the opposite results. Conclusion MiR‐26a affects the function of cardiac fibroblasts by targeting CTGF and probably mediates the process of radiation‐induced myocardial fibrosis, which may become a new regulatory target of RIHD.