Huoxin Pill(活心丸) Attenuates Cardiac Fibrosis by Suppressing TGF-β1/Smad2/3 Pathway in Isoproterenol-Induced Heart Failure Rats

Objective: To evaluate the effects of Huoxin Pill(活心丸, HXP) on cardiac fibrosis and heart failure(HF) in isoproterenol(ISO)-induced HF rats. Methods: Thirty Wistar rats were randomly divided into 5 groups including control, HF, isosorbide mononitrate(ISMN), HXP low(HXP-L), and HXP high(HXP-H) groups(n=6 for each group) according to the complete randomization method. Rats were pretreated with ISMN(5 mg/kg daily), low concentration of HXP(10 mg/kg daily) or high concentration of HXP(30 mg/kg daily) or equal volume of saline by intragastric administration for 1 week, followed by intraperitoneal injection of ISO(10 mg/kg, 14 days), and continually intragastric administrated with above medicines or saline for additional 6 weeks. The effects of HXP treatment on the cardiac function, heart weight index(HWI), pathological changes, and collagen content were further assessed. Moreover, the role of HXP on activation of transforming growth factor-β1(TGF-β1)/Smads pathway was further explored using immunohistochemistry(IHC) and Westernblot assay. Results: HXP treatment significantly alleviated the decrease of ejection fraction(EF) and fractional shortening(FS), while decreased the elevation of left ventricular end-systolic volume(LVESV) in ISO-induced HF rats(P<0.05). Moreover, HXP treatment obviously attenuated the increase of HWI and serum level of creatine kinase MB(CK-MB, P<0.05), as well as pathological changes in ISO-induced HF rats. Further determination indicated that HXP treatment alleviated the elevation of collagen Ⅰ and collagen Ⅲ protein expression in cardiac tissues of ISO-induced HF rats. Furthermore, HXP treatment significantly down-regulated the increase of TGF-β1 and p-Smad2/3 protein expression in cardiac tissues of HF rats(P<0.05), while did not affect the expression of total Smad2/3. Conclusions: HXP attenuated heart failure and cardiac fibrosis in ISO-induced HF rats by suppression of TGF-β1/Smad2/3 pathway.