CXCR2 and CXCL2 expression in mouse colon tissues.

CXCR2 (A) and CXCL1, CXCL2, CXCL3, and CXCL5 (B) mRNA expression in the colons of the two groups sacrificed at the indicated times was assessed by quantitative RT-PCR. Each value represents mean ± SD (n = 7 mice/group). *p<0.05, **p<0.01 versus control mice or day 0 mice. CXCL2⁺ (C, D) and CXCR2⁺ (E) cells were detected in the mouse colon tissues by immunohistochemical analysis. The colons were removed from the AOM and DSS-treated mice at the indicated times. Immunohistochemical analysis was performed using anti-CXCL2 and anti-CXCR2 antibodies, as described in the Materials and Methods. The cell numbers per field were counted in 5 randomly selected visual fields at 400× magnification. Representative results of 7 mice are shown in (C). Values in (D) and (E) represent mean ± SD for 7 mice in each group. *p<0.05, **p<0.01 versus day 0 mice. (F) Neutrophils expressing CXCR2 were detected by double-color immunofluorescence analyses using anti-Ly6G (red) and anti-CXCR2 (green) antibodies, as described in the Materials and Methods. The fluorescent images are digitally merged in the far right image. Representative results of 7 mice are shown. Original magnification, 630×. (G) The number of migratory Neutrophils in response to varying CXCL2 concentrations was counted in >10 randomly selected visual fields at 400× magnification. Values are mean ± SD of 3 independent experiments, expressed as fold increases over the control cells. **p<0.01 versus untreated cells. (H) Results of quantitative RT-PCR of IL-1α mRNA expression are shown. Each value represents mean ± SD (n = 7 mice/group). *p<0.05, **p<0.01 versus control mice or day 0 mice.