FIG. 6.

Comparison of renal cytokine expression in TNF-α-pretreated and TNF-α-posttreated animals. Mice were treated with either 9 μg/kg Stx1 alone, with Stx1 6 h after rmTNF-α exposure (TNF-α pretreatment group), or with rmTNF-α 6 h after Stx1 exposure (TNF-α posttreatment group). At various time points, kidneys were harvested and the expression of the cytokines TNF-α, IL-1β, IL-10, IFN-γ, and GM-CSF in renal tissue homogenates was analyzed as described in Materials and Methods. The data shown are expressed as the fold change of the rmTNF-α pretreatment group or the fold change of the rmTNF-α posttreatment group from results for Stx1 alone at each time point. The experiment was repeated twice with a total of six mice in each group. Statistical significance between cytokine expression by Stx1-treated cells versus treatment groups at each time point was assessed using one-way ANOVA with Tukey's multiple comparison post test. An asterisk denotes significance at P < 0.05, two asterisks denotes significance at P < 0.01, and three asterisks denotes significance at P < 0.001 between the TNF-α treatment group and Stx1 treatment only.