COLITIS-INDUCED CHANGES IN THE LEVEL OF TRACE-ELEMENTS IN RAT COLON AND OTHER TISSUES

Trace elements constitute important prosthetic groups in a number of a ntioxidant enzymes which neutralize free radicals generated during inf lammatory conditions such as colitis. However, the status of trace ele ments in colitis remains to be found. In the present study the concent rations of zinc, copper, manganese and selenium in the colon, liver an d serum of rats with acetic acid (HAc)- or trinitrobenzenesulfonic aci d (TNBS)-induced colitis were measured using atomic absorption spectro photometer. Myeloperoxidase and glutathione peroxidase activities were measured spectrophotometrically. Our results show that the selenium c oncentration was significantly decreased by 33 and 37.5% in the colon and 69 and 78% in liver by HAc and TNBS treatment, respectively. Simil arly the zinc concentration in the colon was decreased by 21 and 28% b y HAc- and TNBS-induced colitis as compared to the controls, but manga nese and copper, remained unaltered. The serum concentrations of coppe r, zinc and selenium also remained unaltered during colitis. The weigh t of HAc-treated rats did not decrease while there was a significant w eight loss in the TNBS-treated rats. Myeloperoxidase activity was incr eased, whereas glutathione peroxidase activity was significantly decre ased in the colon inflamed by HAc or TNBS as compared to the controls. These findings suggest that colitis induces a reduction in the tissue levels of trace elements which is independent of the way colitis is i nduced. Our findings of a reduction in Se and glutathione peroxidase a ctivity together suggest that the reduction in the trace element conce ntrations is not due to dietary factors or malabsorption. The decrease may severely affect the antioxidant potential of the colon and theref ore is a putative factor for the progression of disease.