Paeoniflorin Attenuates Myocardial Fibrosis in Isoprenaline-induced Chronic Heart Failure Rats via Inhibiting P38 MAPK Pathway.

Paeoniforin (Pae) is a monoterpenoid glycoside compound and has many biological activities, such as immunosuppression, anti-inflammation and anti-cell proliferation. However, the effects and mechanisms of Pae on chronic heart failure (CHF) remain unclear. This study was conducted to assess the effects and mechanisms of Pae on myocardial fbrosis in isoprenaline (Iso)-induced CHF rats. Pae (20 mg/kg) was intragastrically administrated to CHF rats for 6 weeks. Cardiac structure and function were assessed. The protein and mRNA levels of transforming growth factor β1 (TGF-β1) and p38 were detected. Compared to Iso group, Pae could alleviate myocardial fibrosis and improve cardiac function in CHF rats. The levels of collagen volume fraction (13.75%±3.77% vs. 30.97%±4.22%, P<0.001) and perivascular collagen volume area (14.32%±2.50% vs. 28.31%±3.16%, P<0.001) were signifcantly reduced in Pae group as compared with those in Iso group. The expression of TGF-β1 protein (0.30±0.07 vs. 0.66±0.07, P<0.05) and mRNA (3.51±0.44 vs. 7.58±0.58, P<0.05) decreased signifcantly in Pae group as compared with that in Iso group. The expression of p38 protein (0.36±0.12 vs. 0.81±0.38, P<0.05) and mRNA (3.84±0.05 vs. 4.40±0.17, P<0.05) also decreased markedly in Pae group as compared with that in Iso group. Pae could attenuate myocardial fbrosis and improve cardiac function in CHF rats by down-regulating the p38 MAPK signaling pathway.