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目的 研究褪黑素对低氧激活的小胶质细胞CD4 5表达的影响 ,以探讨褪黑素的抗衰老和抗阿尔茨海默病的作用机制。方法 体外培养BV 2小胶质细胞 ,用终浓度为 2 .0mmol·L- 1的连二亚硫酸钠作用 4 8h ,造成慢性低氧模型 ,药物处理组在低氧的同时给予褪黑素。相差显微镜下观察小胶细质胞形态学变化 ,流式细胞术测定缺氧状态下BV 2小胶质细胞表面CD4 5的表达 ;体外培养BV 2小胶质细胞用终浓度为 0 .0 1,0 .1,1.0 μmol·L- 1的褪黑素作用5min ,加入 2 0mg·L- 1的脂多糖 37℃孵育 12h ,Griess试剂法检测培养上清中NO的含量。结果 连二亚硫酸钠引起的低氧可明显增加BV 2小胶质细胞CD4 5的表达 ,荧光强度增至 2 3.9± 14 .2 (对照组为0 .80± 0 .73) ,低氧也可使小胶质细胞的形态发生阿米巴样变 ,而 0 .0 1,0 .1,1.0 μmol·L- 1的褪黑素可剂量依赖性地减少低氧诱导的CD4 5表达 ,抑制由低氧引起的小胶质细胞的阿米巴样变。但褪黑素对脂多糖诱导的BV 2小胶质细胞培养液中NO的升高无明显抑制作用。结论 褪黑素抑制小胶质细胞的激活与其抗氧化作用密切相关 ,可能是其抗炎和防治阿尔茨海默病作用的重要理论基础
Objective To investigate the effect of melatonin on the expression of CD4 5 in hypoxia-activated microglia in order to explore the mechanism of melatonin’s anti-aging and anti-Alzheimer’s disease. Methods BV 2 microglial cells were cultured in vitro and treated with sodium dithionite at a final concentration of 2.0 mmol·L -1 for 48 h, resulting in a chronic hypoxia model. The drug-treated group was given hypoxemia with melatonin. Morphology changes of microglial cells were observed under phase contrast microscope. Flow cytometry was used to detect the expression of CD4 5 on BV 2 microglial cells under hypoxia condition. BV 2 microglial cells were cultured in vitro with a final concentration of 0.01 , 0.1, 1.0 μmol·L -1 melatonin for 5 min, 20 mg L -1 lipopolysaccharide was added and incubated at 37 ℃ for 12 h. The content of NO in culture supernatant was detected by Griess reagent method. Results Hypoxia induced by sodium dithionite increased the expression of CD4 5 in BV 2 microglial cells significantly, and the fluorescence intensity increased to 23.9 ± 14.2 (control group, 0.80 ± 0.73) The morphology of microglial cells was changed amoeba, and the melatonin of 0.0101,1.0 μmol·L-1 dose-dependently reduced hypoxia-induced CD4 5 expression, Oxygen-induced amoebiasis of microglia. However, melatonin had no significant inhibitory effect on the increase of NO in lipopolysaccharide-induced BV 2 microglial cell culture medium. Conclusion The inhibition of microglial activation by melatonin is closely related to its antioxidant activity and may be an important theoretical basis for its anti-inflammatory and anti-Alzheimer’s disease effects