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目的:观察血管活性肠肽(VIP)对帕金森病(PD)大鼠黑质多巴胺(DA)能神经元存活和小胶质细胞活化的影响。方法:采用脑立体定位术将6-羟多巴胺注射至纹状体,制备大鼠PD模型。将PD大鼠随机分为VIP组和模型组,VIP组大鼠腹腔注射VIP 1 ml(20 ng/ml)。另10只正常大鼠为对照组。采用免疫组织化学和RT-PCR方法观测各组大鼠黑质DA能(酪氨酸羟化酶(TH)阳性)神经元数量、小胶质细胞(CD11b阳性)的数量和形态变化以及肿瘤坏死因子(TNF-α)和环氧酶-2(COX-2)的表达及相关分子mRNA水平达变化。结果:PD大鼠损毁侧黑质TH阳性神经元数量较对照组明显减少(P<0.05),小胶质细胞(CD11b阳性细胞)数量显著增加(P<0.05),并呈“阿米巴”样改变,TNF-α和COX-2阳性细胞数量明显增加(P<0.05);VIP组大鼠与模型组相比,黑质TH阳性神经元数量明显增加(P<0.05),CD11b阳性细胞数量明显减少(P<0.05),TNF-α和COX-2的阳性细胞数量显著减少(P<0.05)。RT-PCR检测结果可见,模型组大鼠黑质TH mRNA较对照组显著降低,而VIP组TH mRNA较模型组显著升高(P<0.05),模型组CD11b mRNA、TNF-αmRNA表达明显高于对照组,而VIP组大鼠CD11b mRNA、TNF-αmRNA表达显著低于模型组。结论:VIP对6-OHDA所致PD大鼠DA能神经元具有保护作用,并且可以抑制黑质内小胶质细胞活化及相关炎性因子的表达。
Objective: To observe the effect of vasoactive intestinal peptide (VIP) on the survival of dopaminergic neurons and the activation of microglia in substantia nigra of Parkinson’s disease (PD) rats. Methods: 6-hydroxydopamine was injected into striatum by stereotaxic method to prepare rat PD model. The PD rats were randomly divided into VIP group and model group. VIP group rats were injected intraperitoneally with 1 ml of VIP (20 ng / ml). Another 10 normal rats as control group. Immunohistochemistry and RT-PCR methods were used to observe the number of DA neurotrophic factor (tyrosine hydroxylase (TH) -positive), the number and morphological changes of microglia (CD11b-positive) and tumor necrosis (TNF-α) and cyclooxygenase-2 (COX-2) expression and related molecular mRNA level changes. Results: The number of TH positive neurons on the lesioned side of substantia nigra in PD rats was significantly decreased (P <0.05), the number of microglial cells (CD11b positive cells) was significantly increased (P <0.05) (P <0.05). Compared with the model group, the number of TH positive substantia nigra neurons in VIP group increased significantly (P <0.05), and the positive expression of CD11b The number of cells decreased significantly (P <0.05), and the number of TNF-α and COX-2 positive cells decreased significantly (P <0.05). The results of RT-PCR showed that the TH mRNA expression of substantia nigra in model group was significantly lower than that in control group, while the TH mRNA in VIP group was significantly higher than that in model group (P <0.05). The expression of CD11b mRNA and TNF-αmRNA in model group was significantly higher than that in model group In the control group, the expression of CD11b mRNA and TNF-αmRNA in VIP group was significantly lower than that in model group. Conclusion: VIP can protect DA neurons in PD rats induced by 6-OHDA and inhibit the activation of microglia in substantia nigra and the expression of related inflammatory cytokines.