To establish in vitro inflammation models in the BV2 microglias induced by lipopolysaccharide(LPS), and explore the effect of bone marrow mesenchymal stem cells(MSCs)on inflammatory reaction and phenotype conversion of LPS-stimulated BV2 microglias.

Mouse MSCs were isolated and purified by adherence screening. The in vitro routinely cultured BV-2 microglias were divided into PBS control group(group A), PBS plus MSCs treatment group(group B), LPS stimulation group(group C)and LPS plus MSCs group(group D). Transwell assay was used to coculture the MSCs and BV2 microglias(1:1, 2×10⁵ cells/hole), and LPS stimulation concentration was 1 μg/mL; 24 h after each treatment, the supernate and BV2 microglias were collected. Morphological changes of BV2 microglias were observed under microscope; NO concentration in the supernate was detected by Griess reaction; levels of interleukin(IL)-1β, tumor necrosis factor(TNF)-α were detected by ELISA; the mRNA and protein expressions of iNOS and Arg-1 were analyzed by real time-PCR and Western blotting.

MSCs can improve the morphology of activated microglias. The concentrations of TNF-a, IL-1β and NO in culture supernatants in group C were increased significantly as compared with those in group A and group B(P<0.05); as compared with group C, group D had significantly lower levels of TNF-a, IL-1β and NO in culture supernatants(P<0.05); As compared with group A, group B and group C had significantly higher iNOS mRNA and protein expressions(P<0.05), while no significant differences of Arg-1 mRNA and protein expressions were noted(P>0.05); as compared with group C, group B had significantly lower iNOS mRNA and protein expressions and significantly higher Arg-1 mRNA and protein expressions(P<0.05);

MSCs can inhibit the inflammatory reaction of activated microglias, and promote phenotype conversion of inflammatory M1 cells to anti-inflammatory M2 cells, therefore, enjoying significant neuro-protective effects.

Bone mesenchymal stem cell; Microglia; Lipopolysaccharide; Anti-inflammatory