Abstract:

Objective To explore the effect of Vitacamphorae Injection on the myocardial fibrosis induced by isoproterenol(Iso) in the rats,and to clarify its mechanism of anti-myocardial fibrosis,and to provide the basis for its clinical application. Methods 60 SD rats were randomly divided intocontrol group,Iso model group, vitamin C group and different doses of Vitacamphorae Injection groups. The models of myocardial fibrosis in the rats were set up by using subcutaneous injection of 2 mg·kg^-1·d^-1 Iso,for 14 consecutive days,while the rats in different doses of Vitacamphorae Injection groups and vitamin C group were subcutaneouly injected with 0.8,1.6,3.2 mg·kg^-1·d^-1 vitacamphorae and 80 mg·kg^-1·d^-1 vitamin C,for 28 consecutive days. BL-420 E⁺ biological function experimental system was used to detect the rat ECG and heart function after experiment. Thenthe heart mass index (HMI) and left ventricular mass index (LVMI) were measured. The contents of malondialdehyde (MDA),the activities of superoxide dismutase (SOD) and inducible nitric oxide synthase enzyme (iNOS)in the myocardium tissue were measured by UV detection.The activities of the lactate dehydrogenase (LDH) and the contents of nitric oxide (NO) were examined by enzyme labelling instrument.The contents of type Ⅰ (ColⅠ) collagen and type Ⅲ collagen (Col Ⅲ) in the myocardium tissue of the rats were detected by ELISA.The pathological changes of myocardium tissue were observed by HE staining. Results Compared with control group,the heart rate of the rats in Iso model group was increased,the left ventricular systolic pressure (LVSP) was decreased,and the maximum rising rate of left ventricular pressure (LVdp/dt_max) was decreased (P<0.05 or P<0.01); the HMI and LVMI were increased,but there were no significant differences(P>0.05).In left ventricular myocardium tissue,the contents of MDA,Col Ⅰ and Col Ⅲ were increased,while the NO content was decreased(P<0.05 or P<0.01),and the activities of SOD and iNOS were decreased,but the LDH activity was increased(P<0.05 or P<0.01).Compared with Iso model group,the HMI and LVMI of the rats in different doses of Vitacamphorae Injection groups were decreased in a dose-dependent manner;and the contents of MDA,the LDH activities,the Col Ⅰ and Col Ⅲ contents were decreased(P<0.05 or P< 0.01),while the NO contents and the activities of iNOS,SOD were increased(P<0.05 or P<0.01). Conclusion Vitacamphorae Injection could inhibit the myocardial fibrosis induced by Iso in the rats,and its mechanism may be related to antioxidant and increasing the level of NO to inhibit the synthesis of collegen.

Key words: myocardial fibrosis, Vitacamphorae Injection, isoproterenol