Objective    To study the protective effect of water extract from Rhizoma Panacis majoris on cerebral ischemia-reperfusion (I/R) injury in mice.    Methods   Mice were divided into low dose (2.5 g/kg)

medium dose (5.0 g/kg) and high dose (10.0 g/kg) Rhizoma Panacis majoris water extractive of Rhizoma Panacis majoris  groups

nimodipine group and sham group respectively

  after pretreating homologous drugs for 7 days. The mouse model of middle cerebral artery occlusion was induced

and neurological symptom scoring and inclined board testing were performed within 24 h after I/R. The survival rate

infarct volume and neuron density of mice were recorded. The levels of superoxide dismutase (SOD)

glutathione peroxidase (GSH-PX)

catalase (CAT)

malondialdehyde (MDA)

xanthine oxidase (XOD) were measured.    Results    The survival rate was higher in medium and high dose groups than in model group (77.8% and 82.1% vs 51.9%

P0.05). The neurological symptom score and inclined board degree were greater in high dose group than in model group (1.77±0.38 and 63.6±5.5 vs  2.21±0.43 and 55.1±7.5

P0.05)

which were similar to those in nimodipine group. The infarct size and water content were significantly lower in medium and high dose groups than in model group (P0.05)

which significantly increased the activity of SOD

GGSH-PX and CAT while decreased the activity of XOD and MDA level (P0.05). The improvement in activity of SOD

GGSH-PX and CAT was better in high dose group than in nimodipine group.    Conclusion    Pretreatment of water extract from Panacis majoris rhizoma can significantly protect mice against cerebral I/R injury.