[Oxidative stress of deltamethrin on rat nervous system].

Objective: To explore the lipid peroxidation induced by deltamethrin (DM) in the cerebral cortex and hippocampus of rat.

Methods: Wistar male rats were administrated with DM (daily dose was 3.125, 12.500 mg/kg respectively). The content of malondialdehyde (MDA) and the activity of total-superoxide dismutase (T-SOD, including Mn-SOD and CuZn-SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione peroxidase (GSH-Px) and glutathione reductase (GR) in cerebral cortex and hippocampus tissue were determined. The reduced glutathione (GSH) content and gamma-glutamylcysteine synthetase (gamma-GCS) activity in cytosolic fraction of cerebral cortex and hippocampus tissue was determined by reversed-phase high performance liquid chromatographic assay with o-phthalaldehyde pre-column derivation.

Results: (1) MDA content in cerebral cortex of the high dose group was significantly higher than those in the low dose group, and MDA content in hippocampus tissue of the high dose group was significantly higher than those in both the control and the low dose group after 5 d of DM exposure. (2) The activity of T-SOD and CuZn-SOD in cerebral cortex of both high and low dose group were significantly lower than that in the control group, and there was no effect on CAT activity in cerebral cortex (P < 0.01 or P < 0.05). (3) GSH content in cerebral cortex of the high dose group was significantly higher than that in control group (P < 0.05), and that in hippocampus tissue of high dose was significantly lower than that in both control and low dose group (P < 0.05). GR activity of low dose group in cerebral cortex was significantly lower than that in both control and high group [(11.80 +/- 5.15) vs (18.98 +/- 3.68), (17.35 +/- 2.47) U/mg pro] (P < 0.01). Gamma-GCS activity in hippocampus tissue of the high dose group was significantly lower than that in both control and low dose group [(1.75 +/- 0.60) vs (3.17 +/- 0.79), (2.72 +/- 0.75) nmol x mg pro(-1) x min(-1)] (P < 0.01). GR activity in hippocampus tissue of both high and low dose group was significantly lower than that in the control group [(21.63 +/- 4.92), (21.46 +/- 8.89) vs (31.22 +/- 6.97) U/mg pro] (P < 0.05).

Conclusion: The oxidative stress in nerve tissue, which could be resulted from effect of DM on the activity of SOD, gamma-GCS and GR and GSH content, is one of the mechanisms of neuro-toxicity induced by DM; The decreased activity of gamma-GCS and GR may be the primary cause of DM-induced decrease in that GSH content in hippocampus tissue.