Induction of oxidative stress and DNA damage in cervix in acute treatment with benzo[a]pyrene

Benzo[a]pyrene [B(a)P] is one of the most prevalent environmental carcinogens and genotoxic agents. However, the mechanisms of B(a)P-induced oxidative damage in cervical tissue are still not clear. The present study was to investigate the oxidative stress and DNA damage in cervix of ICR female mice induced by acute treatment with B(a)P. Oxidative stress was assayed by analysis of malondialdehyde (MDA), superoxide anion and H2O2, and antioxidant enzymes. The alkaline single-cell electrophoresis (SCGE) was used to measure DNA damage. The contents of MDA and glutathione (GSH), and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were significantly increased in cervix 24, 48 and 72 h after B(a)P treatment of a single dose of 12.5 and 25 mg/kg, while GSH, CAT, SOD and GST had no significant difference with the dose of 50 mg/kg B(a)P at post-treatment time 48 and 72 h except for SOD activity at 48 h which was significant. The maximum values of SOD, CAT, GST and GSH were peaked at 24 h and then decreased gradually while GPx activities and MDA levels persisted for up to 72 h. Superoxide anion, H2O2 and DNA damage changed similarly as the activity of SOD, CAT or GST. Additionally, increases of formamidopyrimidine DNA glycosylase (FPG) specific DNA damage were observed and can be greatly rescued by vitamin C pretreatment. Overall, B(a)P demonstrated a time- and dose- related oxidative stress and DNA damage in cervix.