AIM To study the action of
melatonin on the
expression of CD45 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 -1 for 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.