The effect of restraint stress on the normal colon and on intestinal inflammation in a model of experimental colitis

Stress may induce development of inflammation in animal models of colitis. The effects of restraint stress on oxidative damage and on antioxidants in the normal colonic mucosa were studied. The effect of stress on the severity of indicators of inflammation, as well as the importance of mucosal substance P (SP) as a mediator of this effect were investigated in the TNBS-colitis model. Restraint stress significantly increased malondialdehyde levels and reduced levels of low-molecular-weight-antioxidants in the normal colon. ATP and the mucosal "energy charge" decreased substantially with chronic stress. Chronic stress worsened the extent of inflammation in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Mucosal SP content was not affected by exposure to chronic stress but increased after induction of colitis. The increase was greater when colitis was induced after exposure to stress. We conclude that chronic restraint stress causes oxidative damage to the normal colon and aggravates intestinal inflammation induced by TNBS. This effect may be mediated by SP.