腹腔内注射脂多糖对大鼠黑质多巴胺能神经元和小胶质细胞形态学影响及炎性因子变化

Morphological and inflammatory factor changes of substantia nigra dopaminergic neurons and microglial cells after intraperitoneal injection of lipopolysaccharide in rat

目的观察腹腔注射脂多糖(lipopolysaccharide,LPS)后,大鼠黑质多巴胺能神经元和小胶质细胞形态学变化及炎性因子的变化。方法健康2月龄、12月龄斯普雷格-道利(Sprague-Dawley,SD)大鼠经腹腔注射LPS(1 mg/kg)后,分别于6 h,12 h,24 h,48 h,1周处死,用链霉菌抗生物素蛋白-过氧化物酶连结(streptavidin-peroxidase,SP)法进行抗酪氨酸羟化酶(tyrosine hydroxylase,TH)和抗钙离子结合蛋白1(ionized calcium binding adapter molecule 1,Iba-1)免疫组织化学染色,观察不同时间点脑黑质多巴胺能神经元阳性存活率及黑质小胶质细胞的激活情况。酶联免疫吸附测定(enzyme-linked immunosorbent assay,ELISA)法分别检测相应时间点血及脑脊液中肿瘤坏死因子α(tumor necrosis factorα,TNF-α)、白细胞介素6(interleukin 6,IL-6)及白细胞介素1β(interleukin 1β,IL-1β)的变化。结果腹腔注射LPS(1 mg/kg)后,老龄组大鼠小胶质细胞呈明显激活改变,且早于青年组小胶质细胞的高峰;各组小胶质细胞的激活早于多巴胺能神经元的损毁;老年组脑脊液中各种炎性因子水平高于青年组。结论老化因素与外周炎性介质诱发的中枢神经系统(central nervous system,CNS)炎性反应有关。

Objective To observe the morphological change of dopaminergic neurons and microglia after intraperitoneal injection of lipopolysaccharide（ LPS）. Methods Healthy two-month-and one-year-old SD rats were intraperitoneally injected with LPS（ 1 mg / kg） at6 h,12 h,24 h,48 h,and 1 w,respectively. Anti tyrosine hydroxylase（ TH） and anti ionized calcium binding adapter molecule 1（ Iba-1） immunohistochemial staining was utilized to observe TH positive neurons and activity of microglia in substantia nigra. The level of tumor necrosis factor α（ TNF-α）,interleukin 6（ IL-6） and interleukin 1β（ IL-1β） in blood and cerebrospinal fluid were detected by enzyme-linked immunosorbent assay（ ELISA）. Results Microglia of one-year-old SD rats were activated more significantly,and reached the peak earlier than the young group. The activation of microglia was earlier than the damage of dopaminergic neuron in each non-control group. The level of inflammatory factors in aged group was higher than that in the young group in cerebrospinal fluid. Conclusion Aging factors are related with CNS inflammatory reaction which is induced by the peripheral inflammatory media.