Role of polymorphonuclear leucocytes and oxygen-derived free radicals in the formation of gastric lesions induced by HCl/ethanol, and a possible mechanism of protection by anti-ulcer polysaccharide.

This study examined the role of oxygen-derived free radicals in the pathogenesis of gastric mucosal lesions induced by HCl/ethanol. Superoxide dismutase, and catalase, and their combination reduced gastric lesion formation in mice. Gastric lesions were also reduced in mice treated with cyclophosphamide or anti-neutrophils, but not in mice treated with allopurinol or desulphated-carrageenan. Cobra venom factor did not reduce lesion formation. These results suggested that oxygen-free radicals may contribute to the formation of gastric mucosal lesions induced by HCl/ethanol, and that oxygen radicals were generated from neutrophils but not from xanthine oxidase. Anti-ulcer pectic polysaccharide, bupleuran 2IIc, which was recently isolated from the roots of Bupleurum falcatum L., showed potent inhibition of HCl/ethanol-induced gastric lesions in mice. Bupleuran 2IIc seemed to scavenge hydroxyl radical effectively. It was suggested that this anti-ulcer polysaccharide may provide protection to the gastric mucosa by scavenging oxygen-free radicals.