FIGURE 2

Lipopolysaccharide preconditioning modulates proximal mediators of TNF signaling pathway after MCAO. C57Bl/6 mice were treated with 0.2 mg/kg LPS at 72 h before60 mins MCAO. (A) TNFR1 expression in the cortex of the ischemic hemisphere was measured by Western blot analysis at the indicated times after MCAO. A representative Western blot from five saline- and five LPS-treated mice at 24 h after MCAO is provided. The densitometric values of TNFR1 are plotted as a ratio of TNFR1 expression relative to baseline controls as a function of time after MCAO. Open circles, saline-pretreated mice; black squares, LPS-preconditioned mice. (B) TNFR1 expression was examined by Western blot analysis in the cortex or striatum of the ischemic hemisphere at 24 h after MCAO. Mean densitometric values are expressed relative to ischemic hemisphere of saline pretreated controls. (C) Tumor necrosis factor receptor 1 in the cortex of the ischemic hemisphere was examined by enzyme-linked immunosorbent assay at the indicated times after MCAO. (D) Tumor necrosis factor receptor 1 and TRADD expression was examined by immunofluorescent staining at 24 h after MCAO in both the cortex and striatum of the ischemic hemisphere. The intensity of fluorescence (IF) (middle panel) was measured on a scoring system (0 to 3) within each region of the cortex (as shown) in each mouse brain. Cell phenotype was determined by counterstaining for NSE and colocalization (shown in far right panel) was quantified as described in Materials and methods. For all experiments values are means.e.m., ^* P<0.05 versus saline controls, n=6 to 8 mice/treatment.