Luteolin promotes ramification of microglia and inhibits NO-synthesis. Effects of luteolin, LPS and Luteolin + LPS on BV-2 (A-D) and primary brain microglia (E-H) cell morphology and actin cytoskeleton. Phallodin-TRITC-staining of F-actin bundles and DAPI costaining reveals that 24 h treatment with 50 μM luteolin in non-activated (B, F) or LPS-activated microglia (D, H) supports ramification. (I) NO release from BV-2 cells treated for 24 h with 50 μM luteolin, 50 ng/ml LPS, or LPS + luteolin. The micrographs and data shown are from one representative experiment out of three independent experiments with the same tendencies. Scale bar, 50 μM. (J) Real-time qRT-PCR analysis of iNos transcripts in BV-2 microglia stimulated with 50 μM luteolin, 50 ng/ml LPS, or 50 μM luteolin + 50 ng/ml LPS. Expression was normalized to the control gene Gusb and mRNA levels (+/- SEM) are graphed relative to mock-treated control cells. Results are calculated from two independent experiments performed in triplicate measurements. *** p ≤ 0.001, ** p ≤ 0.01 for LPS vs. control and luteolin + LPS vs. LPS, respectively.