FIGURE 1.

Knock-out of jak3 gene leads to increased severity toward DSS-induced colitis. A, time course of body weight change during DSS-induced colitis. WT and jak3^−/− (KO) mice (n = 6, each group) were treated with water or 2.5% DSS for the indicated periods, and the percent change in body weight was plotted versus days of treatment. B, time course of the disease activity index during DSS treatment. The disease activity index was determined in WT and KO mice as described under “Experimental Procedures” and plotted versus days of treatment. C, MPO in colonic mucosal scrapings. MPO activity was determined as described under “Experimental Procedures.” D and E, histological analysis of DSS-induced colitis. Fresh frozen colonic sections from WT and KO mice were stained with H&E; representative sections are shown with indicated magnifications from each group (n = 6) (D). E, colonic H&E sections from each animal under D were scored in a blinded fashion using protocol described under “Experimental Procedures.” F, colon to body weight ratios of DSS-treated WT (control) and Jak3 KO mice were calculated, and values are shown. A–C, E, and F, values are mean ± S.E. Asterisks indicate statistically significant differences between WT and KO groups (p < 0.05 in at least n = 3 independent experiments).