Objective: Through the establishment of the model of oxidatie stress damage induced by H2O2 in myocardium cells

to observe the protective effects of total saponin from Panax japonicus (SPJ) on myocardial cells. Method: Neonatal rat cardiomyocytes were randomly divided into four groups: normal

model (H2O2)

H2O2+l-SPJ (SPJ

50 mg·L-1) and H2O2+h-SPJ (SPJ

100 mg·L-1). H2O2was used to induce oxidative stress injury in primary cultured cardiomyocytes of neonatal rats for 2 hours

and then incubated 24 hours with SPJ (50

100 mg·L-1). The beating rates of cardiomyocytes were monitored under inverted microscope

cell viability was detected by MTT assay. The content of lactate dehydrogenase (LDH)

malondialdehyde (MDA)

and the activities of superoxide dismutase (SOD)

catalase (CAT)

glutathione peroxidase (GSH-Px) in culture medium were detected after treated by SPJ with colorimetric technique at 24 hours. Result: SPJ could significantly increase beating rates of cardiomyocytes; and the contents of LDH

MDA in culture medium were remarkably decreased

and activities of SOD

CAT and GSH-Px were significantly increased (P<0.05 or P<0.01). Conclusion: SPJ exerted protective effects on oxidative stress injury induced by H2O2 in cardiomyocytes of neonatal rats.