OBJECTIVETo explore the effect of deltamethrin (DM) on production of free radical and transcription factor Nrf2 in rats' brain tissue.

METHODS8 male rats were randomly assigned to four groups and administered with 1% W/W tertiary butylhydroquinone (tBHQ) or olive oil for 3 days, prior to exposure to DM and then with 12.50 mg or 0mg DM/Kg BW for 5 days. The level of free radical in rats' hippocampus tissue was detected by electron spin resonance (ESR) spectroscopy. 18 male rats were randomly assigned to three groups and administered with i.p. (daily dose was respectively 0, 3.13, 12.50 mg/kg DM) for five days. After treatment, Nrf2 protein levels in the cytoplasmic and nuclear fractions of both cerebral cortex and hippocampus tissue were measured by western blot.

RESULTSThe level of free radical in hippocampus tissue of rats administered by DM and pretreatment with tBHQ prior to DM were increased to a 2.45-fold and 2.97-fold of values of control group, respectively (P < 0.05). Nrf2 protein levels in the cytoplasmic fractions of cerebral cortex of both low and high dose group were significantly increased, 1.68- fold and 1.34- fold of values of control group, respectively. Nrf2 protein levels in the nuclear fractions of cerebral cortex of both low and high dose group were increased in a dose- dependent model, 1.51-fold and 2.29-fold of values of control group, respectively (P < 0.01). Nrf2 protein levels in the cytoplasmic fractions of hippocampus tissue of both low and high dose group were increased in a dose- dependent model, 2.26-fold and 3.58-fold of values of control group, respectively. Nrf2 protein levels in the nuclear fractions of hippocampus tissue of both low and high dose group were increased, 2.42-fold and 2.45-fold of values of control group, respectively (P < 0.01).

CONCLUSIONThe studies in vivo demonstrate that DM treatment could induce free radical production and expression of Nrf2 protein in both cerebral cortex and hippocampus tissue and activate Nrf2.