血管活性肠肽(VIP)通过调控脑组织IFN-γ、IL-17A因子水平对实验性自身免疫性脑脊髓炎(EAE)大鼠防治作用的研究

Effect of vasoactive intestinal peptide on prevention and treatment of experimental autoimmune encephalomyelitis rats by regulating the levels of IFN-γ and IL-17A in brain tissue

目的探讨血管活性肠肽(VIP)通过调控脑组织IFN-γ、IL-17A因子水平对实验性自身免疫性脑脊髓炎(EAE)大鼠防治作用。方法将60只健康雌性Wistar大鼠随机分成4组(正常对照组、EAE对照组、VIP低剂量防治组和VIP高剂量防治组),利用髓鞘碱性蛋白(MBP)+完全弗氏佐剂(CFA)诱导建立EAE模型。自造模当日起,每隔1 d分别对VIP低、高剂量防治组大鼠腹腔注射VIP 4 nmol/kg(0.2 ml)、16 nmol/kg(0.8 ml),正常对照组及EAE对照组注射0.8 ml生理盐水,连续10 d。观察大鼠发病情况;HE染色观察脑组织基本病理改变;通过免疫组化技术,利用抗胶质纤维酸性蛋白抗体(GFAP)检测脑组织内的星形胶质细胞活化情况;ELISA法检测脑组织匀浆中IFN-γ、IL-17A因子含量变化。结果 VIP各剂量防治组大鼠发病潜伏期延长、进展期缩短、发病高峰期神经功能障碍评分(NDS)降低,脑组织中炎症细胞浸润程度明显下降、活化的星形胶质细胞即GFAP+细胞数量减少,脑组织匀浆中IFN-γ、IL-17A含量降低,且高剂量组变化更明显。结论 VIP通过降低脑组织中IFN-γ、IL-17A含量,减轻脑组织炎症细胞的浸润程度,抑制星形胶质细胞活化,发挥对EAE的防治作用。

Objective To explore the effect of vasoactive intestinal peptide（ VIP） on the prevention and treatment of experimental autoimmune encephalomyelitis（ EAE） rats by regulating the levels of IFN-γ and IL-17 A in brain tissue.Methods Sixty healthy female Wistar rats were randomly divided into 4 groups： normal control group,EAE control group,VIP low-dose group and VIP high-dose group. Myelin basic protein（ MBP） ＋ complete Freurd＇s adjuvant（ CFA） was used to establish an EAE model. The low and high-dose VIP groups were intraperitoneally injected with VIP 4 nmol / kg（ 0. 2 ml）and 16 nmol / kg（ 0. 8 ml） respectively every other day,while normal control group and EAE group with 0. 8 ml saline for ten consecutive days. The incubation period,progression and peak of neurological dysfunction score（ NDS） changes of rats were recorded. The pathological changes,the GFAP＋astrocyte activation in the brain at the morbidity peak of rats and the cytokine levels of IFN-γ and IL-17 A in brain tissue were observed. Results The incubation period was extended,the progression and peak NDS were shortened in the two VIP groups. In normal control group,there was no inflammatory cell infiltration or active astrocytes in brain tissue. The degree of infiltration of inflammatory cells and the degree of astrocyte activation in the VIP control group were significantly lower than in the EAE group. The cytokine levels of IFN-γ and IL-17 A in brain tissue were reduced in VIP groups. Conclusion By lowering IFN-γ and IL-17 A content in brain tissue,the infiltration of inflammatory cells and astrocyte activation are inhibited. VIP plays an important role in prevention and control of EAE.