[Effect of astragalus on calcium accumulation and SERCA2a gene expression in myocardial tissues in rats with pressure overload-induced left ventricular hypertrophy].

OBJECTIVE: To investigate the effect of astragalus (As) on calcium accumulation and SERCA2a gene expression in left ventricular tissues in rats with pressure overload-induced cardiac hypertrophy. METHOD: cardiac hypertrophy was induced by clipping the abdominal aorta in rats. Male SD rats were allocated to six groups: sham-operrated (Sham), aortic stenosis (Model), model +As-L (5 g x kg(-1) x d(-1)), model+As-M (10 g x kg(-1) x d(-1)), model+As-H (20 g x kg(-1) x d(-1)) and model + captopril (0.05 mg x kg(-1) x d(-1), a positive control). The drugs were administered orally from the 13 th week after surgery. Rats were examined after 12 week treatment with drugs. The cardiac hypertrophy was evaluated by left ventricular mass index (LVMI, left ventricular weight/ body weight). The calcium content in left ventricular tissue was measured by atomic absorption spectrometry. SERCA2a mRNA and protein expressions in left ventricular tissues were determined by half-quantitative RT-PCR and Western blot normalized to abundance of GAPDH mRNA and protein, respectively. RESULT: The increase of LVMI was dose-dependently lessened by As (P < 0.01, P < 0.001). The effect of As-H was similar to that of Captopril. As markedly attenuated calcium accumulation in myocardial tissure (P < 0.01). RT-PCR and Western blot results demonstrated that SERCA2a gene expressions were downregulated (P < 0.05) significantly in model group compared with sham group. As-H upregulated SERCA2a gene expressions (P < 0.05), whereas Captopril had no effect on that. CONCLUSION: The inhibition of As on left ventricular hypertrophy induced by pressure overload in rats may partly contribute to its attenuation of calcium accumulation and up-regulation of SERCA2a gene expressions in left ventricular tissues.