Abstract: Abstract：Objective To investigate the protective mechanism of astragaloside on isoproterenol (ISO) induced myocardial hypertrophy in rats. Methods Twenty-four healthy SPF rats were randomly divided into 4 groups: astragaloside+ISO group [3 mg/(kg·d) ISO intraperitoneal injection, astragaloside 5 mg/(kg·d) gastric lavage], control group (equal volume of normal saline intraperitoneal injection, followed by equal volume of normal saline gastric lavage), ISO group [3 mg/(kg·d) ISO intraperitoneal injection, and normal saline gastric lavage] and astragaloside group [equal volume of normal saline intraperitoneal injection, astragaloside 5 mg/(kg·d) gastric lavage]. Six rats were included in each group and treated for 14 days. After treatment, the left ventricle of rats was taken, and the left heart index (left heart weight/ body weight) was calculated after weighing. The left ventricular tissue was isolated and the occurrence of myocardial hypertrophy was observed by HE staining to compare the myocardial cross-sectional area. Two chlorine fluorescence (DCF) probes to detect the generation rate of myocardial mitochondrial reactive oxygen species (ROS). The protein expression levels of rat myocardial NADPH oxidase 4 (NOX4) and atrial natriuretic peptide (ANP) were detected by Western blot assay. The mRNA expression of myocardial ANP was detected by real-time qPCR. Results Compared with the control group, the left heart index was significantly increased, the myocardial cross-sectional area enlarged, the ROS production rate of myocardial mitochondria increased, NOX4 protein, ANP mRNA and protein expression levels were significantly increased in ISO group (P＜0.05). Compared with the ISO group, the above indicators were significantly improved in ISO + astragaloside group, and the major performance included the reduced myocardial cross-sectional area, decreased ROS generation rate, significantly decreased NOX4 protein, ANP mRNA and protein expressions (P＜0.05). Conclusion Astragaloside has an exact protective effect on myocardial hypertrophy induced by ISO in rats, and which may be related with the decreased oxidative stress by astragaloside.

Key words: ASTRAGALIN, isoproterenol, rats, Sprague-Dawley, cardiomyopathy, hypertrophic, oxidative stress