Figure 5. Effects of M40403 on the 5-FU-induced apoptosis of the small intestinal epithelium. Mice (5 mice/group) were started on a 5-day course of daily intraperitoneal injection of 30 mg/kg 5-FU±5 mg/kg or 10 mg/kg M40403 on day 1. On day 8, small intestinal samples were subjected to microscopic examinations employing TUNEL stain. The number of TUNEL-positive cells was counted per 10 random fields under magnification (×400). Untreated mice served as a control. Representative microscopic pictures (A, B, C, and D) and mean±SD of the number of TUNEL-positive cells (E) of each group were presented. ***p<0.001, (A) Control: untreated control group, (B) 5-FU: 5-FU alone-treated group, (C) 5-FU/M5: 5- FU/5 mg/kg M40403-treated group, (D) 5-FU/M10: 5-FU/10 mg/kg M40403-treated group. TUNEL: Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling.