Carvedilol,nonselective β-adrenoreceptor antagonist,was showed protective effects against acute myocardial infarction(AMI)-induced myocardial injury,however,the mechanisms underlying the antifibrosis effect of carvedilol has not been well known.The aim of the present study was to investigate the potential mechanism for the anti-fibrosis effect of carvedilol against AMI-induced myocardial fibrosis in rats.Methods Male SD rats were randomized into the sham group,LAD surgery-AMI model group,AMI plus low dose of carvedilol treatment group(1 mg /kg per day,CAR-L),AMI plus medium dose of carvedilol treatment group(5 mg /kg per day,CAR-M) and AMI plus high dose of carvedilol treatment group(10 mg /kg per day,CAR-H).The passage 3 neonatal SD rat cardiac fibroblasts were used for hypoxia /normoxia(2 h /4 h) treatment in the presence of carvedilol(0,1,2 and 4 μM).Results Cardiac remodeling and impaired heart function were observed after 14-week LAD surgery treatment,however,and the cardiac remodeling and decreased ejection fraction(EF%) and fractional shortening(FS%) were efficiently rescued in the CAR-M and CAR-H groups.The up-regulated expressions of Col1a1,Col3a1 and α-SMA at mRNA and protein levels were significantly reduced in the CAR-M and CAR-H groups.The in vitro study showed that Col1a1,Col3a1 and αSMA expressions at both mRNA and protein levels were down-regulated by carvedilol in rat cardiac fibroblasts in a dose-dependent manner.Smad3 inhibitors,SIS-3 and naringenin,could efficiently decrease Col1a1,Col3a1 and α-SMA expressions in rat cardiac fibroblasts.Smad3 was shown significantly inactivated in carvedilol-treated rat cardiac fibroblasts.Conclusion Carvedilol negatively regulates Smad3 signal pathway and inhibits extracellular matrix related Col1a1,Col3a1 and α-SMA expressions,contributing to the anti-fibrosis effect of carvedilol against AMI-induced myocardial fibrosis in rats.
Background MicroRNAs(miRNANAs) are endogenous, small non-coding RNAs that negatively regulate gene expression in diverse cardiovascular diseases. However, the roles of miRNANAs in atherosclerogenesis needs to be elucidated. In the present study, the effect of miRNA-21 on pro-atherosclerotic genes expression was examined. Methods The pro-atherosclerotic genes including COX2, VCAM1, ICAM1, MCP1 and miRNA-21 were detected in ox-LDL-treated mouse macrophage RAW264.7 cells. ApoE knock-out(ApoEKO) mice were fed with high-fat diet for 16 weeks, and the abdominal aorta were fixed and used for miRNA-21 hybridization. Lentivirus-based vectors for enforced expression of miRNA-21 and antisense miRNA-21were prepared. The expression of proatherosclerotic genes was determined in the RAW264.7 cells with lentivirusmediated up-regulation of miRNA-21. Results COX2, VCAM1, ICAM1 and MCP1 could be up-regulated by ox-LDL treatment, and 50 μg / mL ox-LDL could significantly increase the expression of above four genes in ox-LDL EAW264.7 cells. miRNA-21 could also be markedly up-regulated in ox-LDL-induced RAW264.7cells. The result of miRNANA hybridization showed that miRNA-21 was strongly expressed in atherosclerotic plaques but not in normal aorta. Lentivirus-mediated over-expression of miRNA-21 could significantly enhance expressions of COX2, VCAM1, ICAM1 and MCP1 in RAW264.7 cells, which could be reversed by antisense miRNA-21 mediated by lentivirus vector. Conclusions miRNA-21 could be modulated by ox-LDL in macrophage RAW264.7 cells, and miRNA-21 could enhance COX2, VCAM1, ICAM1 and MCP1expressions in macrophages.
