A Preliminary Study Of The Regulatory Effect Of MiR-130a On Myocardial Fibrosis After Myocardial Infarction

PartⅠ The expression level of miR-130 a is downregulated and cardiac fibrosis is promoted after myocardial infarction.Object:This part of study is aimed to explore the changes in various indicators of cardiac fibrosis and the expression levels of miR-130 a and ACVR1 b in the heart tissue after myocardial infarction.Methods: Adult C57BL/6 mice were divided into two groups underwent ligation of the left anterior descending coronary artery to create MI group(myocardial infarction model group)and Sham group(sham operation group,only threaded at the same position without ligation).Two weeks after the operation,the hearts of the two groups of mice were taken out.HE staining was used to observe the changes in myocardial tissue;while Masson staining to observe the deposition of collagen fibers;RT-q PCR to detect the nucleic acid expression levels of miR-130 a,ACVR1b and fibrosis indicators;WB to detect the protein level of ACVR1 b and biomarkers of fibrosis.Results:(1)The results of HE and Masson staining showed that the tissues in the infarcted area of the MI group were significantly thinned and collagen fibers deposited significantly;(2)RT-q PCR results showed that the expression of miR-130 a was down-regulated,and the m RNA content of ACVR1 b,collagen 1/3,and matrix metalloproteinase 2/9 increased;(3)WB results showed that ACVR1 b,α-SMA,and collagen 1/3 protein content were found increased in the cardiac tissues of MI group mice in the infarcted area.The above differences are all statistically significant(p<0.05).Conclusion: Myocardial fibrosis occurred after myocardial infarction and was accompanied by the falling of miR-130 a expression and rising of ACVR1 b expression.PartⅡ Mir-130 a regulates the ACVR / SMAD signal path of cardiac fibroblasts and inhibits hypoxia-induced myocardial fibrosisObject : This part of study is aimed to explore the correlation and potential mechanism between the expression level of miR-130 a and the activation of ACVR-Smad signaling pathway in the fibrosis process of hypoxia-treated cardiac fibroblasts.Methods:Mouse neonatal mouse primary cardiac fibroblasts were cultured under hypoxia(O2 3%,24h),and intervened the miR-130 a expression level by transfecting adenovirus tools in advance according to the groups.RT-q PCR was used to detect the changes of nucleic acid levels of miR-130 a,ACVR1b and fibrosis indicators.Activation of the ACVR/Smad signaling pathway was detected by WB.The transwell experiment was used to detect the migration ability of CFs,and the CCK-8 method was used to detect the proliferation activity of CFs.Results:(1)The results of RT-q PCR and WB were similar to the animal experiment,showing that the expression of miR-130 a is down-regulated after CFs were cultured under hypoxia,while the m RNA and protein expressions of ACVR1 b and fibrosis biomarkers are up-regulated.(2)Hypoxia culture enhances the migration and proliferation capabilities of CFs.(3)Transfection of miR-130 a overexpression adenovirus can reduce the increase in fibrosis markers and the enhancement of migration and proliferation caused by hypoxia.(4)Co-transfection of miR-130a-sponge adenovirus can counteract the inhibition to fibrosis caused by the overexpression of miR-130 a mentioned above.(5)ACVR1b is one of the target genes of miR-130 a.Conclusion: Mi R-130 a inhibits cardiac fibrosis caused by hypoxia such as myocardial collagen deposition,fibroblast differentiation,CFs migration and proliferation.Mi R-130 a could inhibit activation of the ACVR-Smad signaling path by targeting the ACVR1 b by targeting the ACVR1 b.