褪黑素对低氧诱导的BV-2小胶质细胞CD45表达增高的抑制作用(英文)

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

Inhibitory effect of melatonin on the elevation of CD45 expression induced by hypoxia in BV-2 microglia

AIM To study the action of melatonin on the expression of CDA5 in BV-2 microglia and the influence of melatonin on BV-2 microglia activation so as to explore the antiaging and anti-Alzheimer's disease mechanisms of melatonin.METHODS Hypoxia in cultured BV-2 microglia was induced by sodium dithionite 2.0 mmol· L- 1for 48 h.The expression of CD45 on the BV-2 microglia surface was measured by flow cytometry,the morphological changes of BV-2 microglia were photographed with the phase-contrast microscope.BV-2 microglia were exposed to 20 mg· L-1 lipopolysaccharides 5 min after treated with 0.01,0.1,1.0 μmol· L- 1 of melatonin,then incubated for 12 h.NO level in the medium was determined by Griess reagent.RESULTS The fluorescent intensity produced by CD45 expression in BV-2 microglia increased from 0.80 ± 0.73(normal control)to 23.9 ± 14.2(hypoxia model).Melatonin(0.01,0.1,1.0 μmol·L- 1 )significantly inhibited the elevation of CD45 expression in microglia in a concentration dependent manner,the fluorescent intensity is 9.3 ± 3.1,7.0 ± 4.85 and 5.4 ± 1.0,respectively.Melatonin could inhibit the morphological change of BV-2 microglia to amebocyte.But melatonin did not antagonize the increase in NO level in the medium induced by lipopolysaccharide.CONCLUSION Melatonin inhibiting the microglia activation by its anti-oxidative action might be an important theoretical basis of anti-inflammation and anti-Alzheimer' s disease effects.