Objective To investigate the effect of Sanshentongmai (SSTM) mixture on the regulation of oxidative damage to rat cardiomyocytes (H9C2) through microRNA-146a and its mechanism.

Methods H9C2 were cultured in vitro, H₂O₂ was used as an oxidant to create an oxidative damage model in H9C2 cells. SSTM intervention was administered to the H9C2 cells. Then, the changes in H₂O₂-induced oxidative damage in H9C2 cells and the expression of microRNA-146a were observed to explore the protective effect of SSTM on H9C2 and its mechanism. H9C2 cells cultured in vitro were divided into 3 groups, including a control group, a model group of H₂O₂-induced oxidative damage (referred to hereafter as the model group), and a group given H₂O₂ modeling plus SSTM intervention at 500 μg/L for 72 h (referred to hereafter as the treatment group). The cell viability was measured by CCK8 assay. In addition, the levels of N-terminal pro-brain natriuretic peptide (Nt-proBNP), nitric oxide (NO), high-sensitivity C-reactive protein (Hs-CRP), and angiotensin were determined by enzyme-linked immunosorbent assay (ELISA). The expression level of microRNA-146a was determined by real-time PCR (RT-PCR).

Result H9C2 cells were pretreated with SSTM at mass concentrations ranging from 200 to 1500 μg/L. Then, CCK8 assay was performed to measure cell viability and the findings showed that the improvement in cell proliferation reached its peak when the mass concentration of SSTM was 500 μg/L, which was subsequently used as the intervention concentration. ELISA was performed to measure the indicators related to heart failure, including Nt-proBNP, NO, Hs-CRP, and angiotensin Ⅱ. Compared with those of the control group, the expressions of Nt-proBNP and angiotensin Ⅱ in the treatment group were up-regulated (P<0.05), while the expression of NO was down-regulated (P<0.05). There was no significant difference in the expression of Hs-CRP between the treatment group and the control group. These findings indicate that SSTM could effectively ameliorate oxidative damage in H9C2 rat cardiomyocytes. Finally, according to the RT-PCR findings for the expression of microRNA-146a in each group, H₂O₂ treatment at 15 μmol/L could significantly reduce the expression of microRNA-146a, and the expression of microRNA-146a in the treatment group was nearly doubled compared with that in the model group. There was no significant difference between the treatment group and the control group.

Conclusion SSTM can significantly resist the H₂O₂-induced oxidative damage of H9C2 cells and may play a myocardial protective role by upregulating microRNA-146a.