Objective: To investigate the protective effect of the formula of Herba Erigerontis and Radix Paeoniae Rubra on H2O2-induced oxidative stress damage of PC12 cells and its possible mechanism. Method: The in vitro model of oxidative stress damage based on PC12 cells was established by treating with H2O2 (850 μmol·L-1) for 6 h. The formula of Herba Erigerontis and Radix Paeoniae Rubra with different concentrations (6.25

12.5

25

50

100 mg·L-1) pretreatment of PC12 cells (3×104-4×104 cells/mL)for 24 h. The MTT assay was used to determine the survival rate of PC12 cells. The activity of LDH in culture medium

the level of malondialdehyde(MDA) and the activity of superoxide dismutase(SOD) in cell lysis solution were detected by colorimetric method. The fluorescent probe DCFH-DA and Rhodamine 123 reagent were employed to determine the level of intracellular reactive oxygen species (ROS) and the changes of mitochondrial membrane potential(Δψm) by flow cytometry

respectively. Result: Compared with the controls

the H2O2 model showed decreased to 52.78% in survival. The LDH release in culture supernatants increased 110.13 U·L-1. In addition

the level of MDA and intracellular ROS were significantly increased

the activity of SOD and the Δψm were significantly decreased(P<0.01). Compared with model group

the survival rate of injured cells was increased

and the activity of LDH

the level of MDA and intracellular ROS were decreased in the formula group. In addition

the activity of SOD and the Δψm were significantly increased(P<0.05

P<0.01) in a certain range. Conclusion: The formula of Herba Erigerontis and Radix Paeoniae Rubra has the significant protective effects on the PC12 cells injured by H2O2

which may be associated with the inhibited of lipid peroxidation

the increased of antioxidase activity

the decrease of ROS and the increased stability of mitochondrial membrane potential.