Department of Cardiology, East Hospital, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Eur Rev Med Pharmacol Sci. 2019 Sep;23(18):8087-8094. doi: 10.26355/eurrev_201909_19026.
The aim of this study was to investigate the effect of micro-ribonucleic acid-195 (miR-195) on myocardial fibrosis in hypertensive rats through the transforming growth factor beta 1 (TGFβ1)-Smad3 signaling pathway.
Spontaneously hypertensive rats (SHRs) were selected in this study to establish the animal model. The content of miR-195 in the model group and control group was measured, respectively. Arterial blood pressure, liver function and myocardial function in the two groups were detected and examined. Pathological changes in rat myocardial tissues were detected via hematoxylin-eosin (HE) staining. After that, myocardial fibroblasts were collected and added with miRNA inhibitors and mimics to suppress and overexpress miR-195. Thereafter, Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting were employed to detect the mRNA and protein expression levels of checkpoint kinase 1 (Chek1) and alpha-smooth muscle actin (α-SMA) (important molecules for proliferation and differentiation of myocardial fibroblasts), as well as the related pathway TGFβ1-Smad3. Furthermore, the effects of miR-195 on myocardial fibrosis in hypertensive rats via the TGFβ1-Smad3 signaling pathway were comprehensively observed.
Serum alkaline phosphatase (ALP), glutamic pyruvic aminotransferase (ALT) and creatine kinase (CK) levels in the SHR group were significantly higher than those of the normal group. Cardiac function examination showed that SHR group had significantly reduced fractional shortening (FS, %) and ejection fraction (EF, %) in comparison with the normal group. However, systolic blood pressure, diastolic blood pressure, left ventricular end-diastolic dimension (LVEDd) and left ventricular end-systolic dimension (LVESd) were markedly elevated in the SHR group. In addition, the miR-195 expression level was remarkably reduced in hypertensive rats. Histopathological changes in rat myocardial tissues were detected through HE staining. The results showed that the normal group had orderly arranged myocardial cells. However, SHR group showed disorderly arranged myocardial cells, thickened myocardial fibers and myocardial fibrosis. RT-PCR assay results revealed that the mRNA levels of Collagen, Chek1, α-SMA, TGFβ1 and Smad3 in rat myocardial fibroblasts were significantly reduced in Mimics group (p<0.05) and increased in Inhibitors group (p<0.05). Western blotting results demonstrated that, compared with the control group, the protein levels of α-SMA, TGFβ1 and Smad3 in rat myocardial cells decreased significantly in Mimics group (p<0.05). Opposite results were observed in Inhibitors group (p<0.05). The above results suggested that overexpression of miR-195 inhibited the expressions of TGFβ1-Smad3 signaling pathway and related molecules, further repressing myocardial fibrosis.
MiR-195 participates in the development and progression of myocardial fibrosis in hypertensive rats through the TGFβ1-Smad3 signaling pathway. Furthermore, this can inhibit the development of myocardial fibrosis in hypertensive rats and prevent myocardial diseases.
本研究旨在通过转化生长因子β 1（TGFβ1）-Smad3 信号通路研究微小 RNA-195（miR-195）对高血压大鼠心肌纤维化的影响。
选择自发性高血压大鼠（SHR）建立动物模型。分别测量模型组和对照组中 miR-195 的含量。检测两组大鼠的动脉血压、肝功能和心肌功能。通过苏木精-伊红（HE）染色检测大鼠心肌组织的病理变化。收集心肌成纤维细胞，加入 miRNA 抑制剂和模拟物以抑制和过表达 miR-195。然后，采用逆转录-聚合酶链反应（RT-PCR）和 Western blot 检测细胞周期检查点激酶 1（Chek1）和α-平滑肌肌动蛋白（α-SMA）（心肌成纤维细胞增殖和分化的重要分子）的 mRNA 和蛋白表达水平，以及相关通路 TGFβ1-Smad3。此外，还综合观察了 miR-195 通过 TGFβ1-Smad3 信号通路对高血压大鼠心肌纤维化的影响。
SHR 组血清碱性磷酸酶（ALP）、谷丙转氨酶（ALT）和肌酸激酶（CK）水平明显高于正常组。心功能检查显示，与正常组相比，SHR 组的射血分数（EF，%）和短轴缩短率（FS，%）明显降低。然而，SHR 组的收缩压、舒张压、左心室舒张末期内径（LVEDd）和左心室收缩末期内径（LVESd）明显升高。此外，高血压大鼠的 miR-195 表达水平明显降低。通过 HE 染色观察大鼠心肌组织的组织病理学变化。结果表明，正常组心肌细胞排列有序。然而，SHR 组心肌细胞排列紊乱，心肌纤维增厚，心肌纤维化。RT-PCR 检测结果显示，在模拟物组（p<0.05）大鼠心肌成纤维细胞胶原、Chek1、α-SMA、TGFβ1 和 Smad3 的 mRNA 水平降低，而在抑制剂组（p<0.05）升高。Western blot 结果表明，与对照组相比，模拟物组大鼠心肌细胞中 α-SMA、TGFβ1 和 Smad3 的蛋白水平显著降低（p<0.05）。在抑制剂组观察到相反的结果（p<0.05）。以上结果提示 miR-195 通过 TGFβ1-Smad3 信号通路参与高血压大鼠心肌纤维化的发生和发展，进一步抑制高血压大鼠心肌纤维化的发展，预防心肌疾病。
miR-195 通过 TGFβ1-Smad3 信号通路参与高血压大鼠心肌纤维化的发生和发展，可抑制高血压大鼠心肌纤维化的发展，预防心肌疾病。
