Caveolin-1 protects against DSS-induced colitis through inhibiting intestinal nitrosative stress and mucosal barrier...

Caveolin-1 (Cav-1) is a multifunctional protein and critical for the production of nitric oxide (NO) in intestinal physiological and pathological conditions, but its role in the inflammatory bowel disease(IBD) are still controversial. In this study we tested the hypothesis that Cav-1 could be an important cellular defense against IBD through inhibiting nitrosative stress and mucosal barrier damage. Male wild-type mice and Cav-1 knockout (Cav-1^-/-) mice were subjected to 3% dextran sodium sulfate(DSS) for 7d to establish the experimental colitis model. A representative iNOS inhibitor (1400 W) was adopted to suppress the activity of iNOS in parallel group. Body weight and disease activity index were monitored. The colon tissues were evaluated through histological analysis. We found Cav-1 was down-regulated in the colon tissue and accompanied with the increase of iNOS and NO levels after DSS administration. Cav-1^-/- mice were greatly increased susceptibility to DSS-induced colitis with the more weight loss and higher disease score than WT mice. Ablation of Cav-1gene significantly resulted in RNS overproduction, tight junctions impaired and inflammation elevated, which aggravated the severity of the intestinal damages. Furthermore, pharmacologic inhibition of iNOS by 1400 W significantly attenuated DSS-induced colitis in both WT and Cav-1^-/- groups. Our results revealed an important role of Cav-1 in preventing intestinal nitrosative stress and mucosal barrier damage in the development of DSS-induced colitis.