Effect of zinc supplementation on trace elements and intestinal metallothionein concentrations in experimental colitis in the rat

Background and Aim. Zinc enhances cell protection against infection and injury and the healing processes themselves. We evaluated the effect of zinc supplementation at different doses on a model of experimental colitis in the rat. Methods. Colitis, induced by intro-rectal instillation of dinitrobenzen-sulphonic acid, was assessed at 1 week by examining: general outcome and macroscopic damage, myeloperoxidase activity, mucosal zinc, iron and metallothionein concentrations. Rats received zinc sulphate, 2 mg/kg or 30 mg/kg, twice a day by gavage for 9 days, starting 3 days before the induction of colitis, or intrarectal instillation of zinc (20 mg/kg) once daily starting S hours after the induction of colitis and for 6 days thereafter. Results. Zinc-treated rats had less diarrhoea, higher body weight and lower colonic weight than untreated rats but no effect was observed on macroscopic inflammation, adhesions, colonic distension and neutrophil infiltration of the colonic mucosa. Zinc supplementation did not affect mucosal iron and zinc concentrations or plasma zinc levels in colitic rats. Metallothionein synthesis was induced in control rats and to a lesser extent in colitic rats. Conclusion. Zinc administration induces metallothionein synthesis but has little effect on the short-term course of experimental colitis.