Potentiation of LPS-induced TNF-α mRNA expression by low concentrations of corticosterone
. (A) BV-2 cells were incubated with 10, 50, and 100 ng/mL LPS for 24 h. (B) Cells were exposed to 50 nM 11-dehydrocorticosterone, which requires conversion to corticosterone by 11β-HSD1, or 25 nM corticosterone for 24 h prior to incubation with 50 ng/mL LPS for another 24 h. TNF-α mRNA expression was measured by real-time RT-PCR. Data (mean ± SD of three independent experiments) represent ratios of TNF-α mRNA to GAPDH control mRNA from treated cells normalized to the values obtained from cells incubated with vehicle (DMSO). *P <0.05, ***P <0.005.