Objective To evaluate the in vitro anti-hypertrophic effect of total Glycosides of Ranunculus Japonius(TGRJ). Methods Neonatal rat cardiomyocytes were cultured and hypertrophy was induced by administrating isoproterenol(ISO, 10 μmol/L) or angiotensin Ⅱ(Ang Ⅱ, 1 μmol/L) for 48 hours. In the treatment groups, cells were pretreated with TGRJ(0.3 g/L) for 30 minutes prior to hypertrophic stimuli. The anti-hypertrophic effects of TGRJ were examined by measuring cell size, total protein content, and protein synthesis. Intracellular free Ca2+ concentration([Ca2+]i) was evaluated using fluorescence dye Fura-2/AM. Sacroplasmic/endoplasmic reticulum Ca2+ ATPase 2a(SERCA2a), atrial natriuretic peptide(ANP), B-type natriuretic peptide(BNP), and beta-myosin heavy chain(β-MHC) protein expression levels were measured by Western blotting. SERCA2 a activity was assayed by p-nitrophenal phosphate disodium salt hexahydrate method. Results Increased cell size, total protein content, and protein synthesis following ISO or Ang Ⅱ stimulation were significantly inhibited by pretreatment with TGRJ(all P<0.05). This anti-hypertrophic effect of TGRJ was confirmed by its suppressing effect on elevated expression of the three hypertrophic related genetic markers, ANP, BNP, and β-MHC. In addition, TGRJ inhibited ISO or Ang Ⅱ induced up-regulation of [Ca2+]i under chronic but not acute conditions. And ISO or Ang Ⅱ induced down-regulation of SERCA2 a expression and activity was also effectively rectified by TGRJ pretreatment. Conclusions The results of present study suggested that TGRJ could prevent ISO or Ang Ⅱ induced cardiac hypertrophy through improving chronic [Ca2+]i disorder, might via normalizing SERCA2 a expression and activity.
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