Effects of spermidine on LPS-induced expression of iNOS and COX-2 mRNA and protein in BV2 microglia. (A) BV2 cells were pretreated with different concentrations of spermidine for 1 h followed by LPS stimulation for another 6 h. Total RNAs were isolated, and mRNA levels of iNOS and COX-2 were measured by RT-PCR. GAPDH expression was used as an internal control. (B) After 24 h treatment, the cells were lysed and the cellular proteins (50 μg) were separated by electrophoresis on SDS-polyacrylamide gels and transferred onto nitrocellulose membranes. The membranes were probed with the indicated antibodies and the proteins were visualized using an ECL detection system. ERK was used as an internal control.