8-OHdG and LPO levels of the collected ovarian tissues were determined using an ELISA kit, according to the manu-facturer’s instructions (Shanghai Hengyuan Biotechnology Co., Ltd,Shanghai, China). The collected mouse ovaries were cracked with lysate. Each 10 mL henylmethane-sulfonyl (PMSF) was added in 1 mL radio immuno precipitation assay (RIPA) as lysate. Every 1 g of tissue with 9 mL lysate, then coated with mouse antibody against 8-OHdG or LPO. After incubation and washing concentrations of 8-OHdG or LPO were determined as described previously .Intra-and inter-CVs: 8-OHdG (6.3%, 8.1%), LPO (5.2%, 7.4%).