Fetal bovine serum (fbs)

Primary cultures of hippocampus neurons were obtained and cultured according to previously described protocol (12) . Briefly, primary rat hippocampus samples were prepared from Sprague-Dawley rat brains at embryonic days 1-3, which were purchased from the Experimental Animal Center of China Medical University (Beijing, China) and were dissected in calcium-and magnesium-free Hank's balanced salt solution (Beyotime Institute of Biotechnology, Haimen, China), following incubation with a 0.25% trypsin solution for 30 min at 36˚C in order to obtain primary hippocampus neuron cells. Cells were maintained in Dulbecco's modified Eagle's medium (DMEM)/high glucose, horse serum containing 10% fetal bovine serum, 1% L-glutamine (3.6 mM), and 1% penicillin antibiotics and were grown in a 5% CO 2 atmosphere at 37˚C. The primary rat hippocampus cells were cultured on plates which were coated in the fetal bovine serum (Beyotime Institute of Biotechnology) and were cultured at 37˚C in humidified air. Two-thirds of the growing medium was changed every 2-3 days and the cells were subcultured roughly once a week. On day 12 of culturing, the incubation media were replaced with media with H 2 O 2 (3, 30 and 300 µmol/l) to achieve oxidative stress injury. Following incubation for 30 min, NAC was added to the media at concentrations of 1, 10, 100 or 1,000 µmol/l.