[Protective effects of Leonurus japonicas on myocardial remodeling induced by isoproterenol in rats].

OBJECTIVE

To investigate the effects of Leonurus japonicas on myocardial remodeling induced by isoproterenol (ISO) in rats.

METHODS

The model of rat myocardial remodeling was established by subcutaneous injection of ISO (20,10 and 5 mg/kg for 3 days, subsequently 3 mg/kg for 7 days). Rats were randomly divided into five groups: Control, ISO, ISO + enalapril, ISO + Leonurus 8 g/ kg and ISO + Leonurus 16 g/kg. Recorded the values of LVSP, LVEDP, +/- dp/dt (max), cardiac output ( CO). Weighed the body weight (BW), heart weight (HW) and left ventricular weight (LVW) of rats to calculate the values of HW/BW and LVW/BW. The hydroxyproline contents were investigated by spectrophotometric measurement. The contents of type I collagen and type III collagen and ratio of I/III collagen were assessed by immunohistochemical stain.

RESULTS

Leonurus (16 g/kg x day(-1)) could increased the value of LVSP, + dp/dt(max), CO (P < 0.05). Leonurus (8 g/kg) could increased the value of -dp/dt(max), decreased the ratios of HW/BW and LVW/BW (P < 0.05), the contents of hydroxyproline, type I collagen, type III collagen and the ratios of I/III collagen (P < 0.05).

CONCLUSIONS

Leonurus at a dosage of 16 g/kg may improve the systolic function; Leonurus at a dosage of 8 g/kg may improve the diastolic function, down-regulate the expression of collagen and normalize the ratio of I/III collagen.