LPS enhances expression of proinflammatory ligands, CORT-suppressible activation of STAT3, but not expression of GFAP.

Abstract

<p>Mice were administered LPS (2 mg/kg, s.c.), CORT (20 mg/kg) or CORT (20 mg/kg) 30 minutes prior to LPS (2 mg/kg). Mice were killed at the post-dosing times indicated or at 6 hours post dosing for the LPS and CORT/LPS groups analyzed for pSTAT3^{tyr 705}. Mice were killed by focused microwave irradiation to preserve steady-state phosphorylation of pSTAT3^{tyr 705} and striatal phosphorylation was analyzed by quantification of scans of pSTAT3^tyr705 immunoblots. Separate groups of mice were used to prepare total striatal RNA from one side of the brain for qRT-PCR analysis of <i>Tnf-α</i>, <i>Osm</i>, <i>Ccl2</i> or <i>Lif</i> and to prepare total striatal protein homogenates from the other side of the brain for ELISA of GFAP. All data points represent mean ± SEM, N = 5. * denotes statistical significance of at least p<0.05 for the LPS alone and CORT/LPS groups compared to saline and # denotes statistical significance of at least p<0.05 for CORT- pretreated LPS group compared to LPS only exposed group. Statistical significance was measured by one or two-way ANOVA. Where significant differences were found, Fisher's LSD Method of post hoc analysis was performed. See Methods for other details on dosing regimens.</p