SAA protects from experimental colitis. SAA knockout mice (n = 7; white bars) or age and sex-matched controls (n = 7; black bars) were treated with 3% DSS in their drinking water for 6 days, while control mice (n = 5 per group) received normal water. Colon length (A), hematocrit (B), bodyweight gain (C), and histological disease index (D) were determined on day 8. Only differences in colon length and hematocrit values were statistically significant (P < 0.05, ANOVA). Real-time PCR analysis of colon tissue samples revealed significant increases in expression of TNFα and osteopontin (OPN) in colon tissue samples of DSS-treated DKO mice (E and F respectively; asterisks indicate significant differences with other groups (ANOVA and post-hoc analysis; P < 0.05)).