RESUMO
<p><b>OBJECTIVE</b>To study the effects of melatonin (MT) on nerve cell apoptosis and the expression of bcl-2 and cytochrome C genes in rat cerebrum with deltamethrin induction.</p><p><b>METHODS</b>35 male Wistar rats were randomly divided into five groups (eight rats per group): olive oil control, deltamethrin-treated (12.5 mg/kg), deltamethrin plus melatonin (25.0 mg/kg, 50 mg/kg and 100 mg/kg respectively) group. Animal models were established by intraperitoneal injection deltamethrin in rats. Nerve cell apoptosis and the protein expression of bcl-2 and cytochrome C genes were detected by flow cytometry with PI staining and immunohistochemistry respectively.</p><p><b>RESULTS</b>Compared with DM group (20.73 +/- 3.34), the positive expression gradation of the bcl-2 protein in nerve cell was increased significantly in MT groups (DM + MT(25) was 45.26 +/- 3.84, DM + MT(50) 39.4 +/- 4.04 and DM + MT(100) 34.4 +/- 4.52) (P < 0.05) but significantly lower than the control group (59.33 +/- 4.03). Compared with DM group (34.86 +/- 4.15), the cytochrome C protein in nerve cell was decreased significantly in MT groups (20.53 +/- 3.17, 28.73 +/- 2.61 and 28.66 +/- 4.82 respectively) (P < 0.05). Compared with DM group (23.06 +/- 3.63), the apoptotic rate in nerve cell was decreased significantly in MT groups [(15.0 +/- 1.77)%, (14.88 +/- 1.84)% and (11.75 +/- 1.93)% respectively] (P < 0.05).</p><p><b>CONCLUSION</b>MT can protect nerve cell against deltamethrin induced brain injury by inhibiting nerve cell apoptosis, downregulate the protein expression of cytochrome C gene and upregulate the protein expression of bcl-2 gene.</p>