摘要目的 观察褪黑素(MT)对溴氰菊酯(DM)引起的大鼠大脑海马脑神经细胞凋亡率、Bcl-2蛋白表达水平及细胞色素C表达的影响.方法 40只Wistar雌性大鼠随机分为5组:橄榄油对照组(1 ml/kg橄榄油)、单纯DM组(12.5 mg/kg DM)、DM+MT25组(25.0 mg/kg MT+12.5mg/kg DM)、DM+MT50组(50 mg/kg MT+12.5 mg/kg DM)、DM+MT100组(100 mg/kg MT+12.5 mg/kg DM),每组8只,一次性给药24 h后,每组大鼠分别断头处死.应用流式细胞术测大鼠海马细胞凋亡率;应用免疫组化和计算机显微图像分析技术测大鼠海马神经细胞中Bcl-2蛋白表达水平和细胞色素C的表达.结果 DM+MT25、DM+MT50、DM+MT100各组Bcl-2蛋白表达水平分别为(45.26±3.84)、(39.40±4.04)、(34.40±4.52),明显低于对照组(59.33±4.03),但明显高于单纯DM组(20.73±3.34),差异均有统计学意义(P＜0.05);DM+MT25、DM+MT50、DM+MT100组的细胞色素C表达水平分别为(20.53±3.17)、(28.73±2.61)、(28.66±4.82),DM+MT50、DM+MT100组细胞色素C表达水平明显高于对照组,3个MT剂量组均明显低于对单纯DM组,且差异均有统计学意义(P＜0.05).3个MT剂量组神经细胞凋亡率分别为(15.00±1.77)%、(14.88±1.84)%、(11.75±1.93)%,明显低于单纯DM组(23.06±3.63)%,但高于对照组(5.69±1.37)%,差异有统计学意义(P＜0.05).结论 MT能够抑制DM引起的大鼠海马神经细胞中Bcl-2蛋白水平的降低和细胞色素C的升高,抑制细胞凋亡率,MT可能通过改变蛋白的表达水平和抗凋亡能力发挥脑保护作用.

abstractsObjective 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.Methods 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.Results 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+MT25 was 45.26±3.84,DM+MT50 39.4±4.04 and DM+MT100 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 signifi-cantly 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).Conclusion MT can protect nerve cell against deltamethrin induced brain iniury by inhibiting nerve cell apoptosis,downregulate the protein expression of cytochrome C gene and upregulate the protein expression of bcl-2 gene.