ABSTRACT
Objective To explore the potential role and function of miR-30 a in myocardial fibrosis after myocardi-al infarction( MI) .Methods We constructed the AAV plasmid vector which carried the miR-30 a gene of rat.The recombinant plasmid was detected by gene sequencing , enzyme digestion and PCR .Virus was packaged into HEK293 cells and virus titer was determined after extraction and purification by PCR .PBS fluid, rAAV9-miR-30 a-NC and rAAV9-miR-30 a were transmited to rat hearts from PBS group , miR-30 a-NC group and miR-30 a group respectively through transcoronary infusion before anterior descending coronary artery ligation .Sham group was set up at the same time.After 4 weeks, heart function was monitored by serial echocardiography , including fractional shortening ( FS) , and left ventricular ejection fraction ( LVEF) .Masson staining was used to calculate collagen volume fraction ( CVF) .The expression of collagen ⅠandⅢwere detected by immunohistochemistry . The mRNA level of miR-30a, TGF-β1 and CTGF were detected by real-time PCR.The protein level of TGF-β1 and CTGF were detected by western blot analysis .Results The cardiac function of miR-30 a group was improved significantly compared with PBS group and miR-30a-NC group (P<0.05).The levels of CVF,collagenⅠ,Ⅲexpression and Collagen Ⅰ/Ⅲ ratio in miR-30 a group was significantly lower than PBS group and miR-30 a-NC group ( P<0.01 ) .The mRNA and protein level of TGF-β1 and CTGF in miR-30 a group were reduced signifi-cantly than PBS group and miR-30 a-NC group ( P<0.001 ) .Conclusions The overexpression of miR-30 a after MI may reduce the mRNA and protein level of TGF-β1 and CTGF, so as to suppress myocardial fibrosis and im-prove cardiac function.