Mesenchymal stem cells inhibits BV2 microglia proliferation independent of nitric oxide. (a) BV2 cells and Mesenchymal stem cells (MSC) were seeded at a 1:0.2 ratio in a 96-well plate with 1 μg/ml lipopolysaccharide (LPS) and 1000 μm N-nitro-L-arginine methyl ester (L-NAME) for 48 hours, and BV2 proliferation was determined with a tritiated thymidine (3H-TdR) incorporation assay. Values are expressed as mean ± SD of percentage BV2 proliferation from three independent experiments. (b) NO2
- concentration in culture supernatant was determined using the Griess assay. BV2 cells and MSC were cultured in 12-well plates at a 0.2 ratio (BV2: MSC) and stimulated with 1 μg/ml LPS, and NO2
- was assayed at 48 hours. Values are expressed as mean ± standard deviation of NO2
- in μm from three independent experiments. *P < 0.01, versus BV2 cells; #P < 0.01, versus BV2 +μlPS.