Berberine Attenuates Cardiac Hypertrophy Through Inhibition of mTOR Signaling Pathway

Purpose Berberine was reported to exert beneficial effects on cardiac hypertrophy. However, its cellular and molecular mechanisms still remained unclear. Methods Cardiac hypertrophy was induced in male Sprague-Dawley (SD) rats by transverse aorta constriction (TAC), with or without 6-week treatment of berberine. Echocardiography was performed to evaluate cardiac function. Rats were then sacrificed for histological assay, with detection for proteins and mRNA. H9c2 cells were pretreated with berberine of different concentrations (0, 1 mu M, and 10 mu M), followed by treatment with 2 mu M norepinephrine (NE). Cells of different groups were measured for cell surface area, with mRNA detected by qRT-PCR and proteins by western blot. Results Compared with the sham group, rats of the TAC group showed significantly increased cardiac hypertrophy and fibrosis, which could be ameliorated by treatment with berberine. Western blot showed that mammalian target of rapamycin (mTOR) signaling-related protein expressions, including phospho-mTOR, phospho-4EBP1, and phospho-p70 S6K (Thr389), but not phospho-p70 S6K (Ser371), were significantly increased in the TAC group, which were inhibited by berberine treatment. H9c2 cells were treated with NE to induce hypertrophy with increased cell surface area and mRNA expressions of anp and bnp. Berberine of 10 mu M, but not 1 mu M, significantly ameliorated NE-induced hypertrophy and inhibited protein expressions of mTOR signaling pathway similar to those in the rat model. Conclusions Berberine can exert cardioprotective effects on both pressure-overloaded cardiac hypertrophy and failure in vivo and NE-induced hypertrophy in vitro. Our results suggest berberine could be a potential treatment for patients with cardiac hypertrophy and failure.