Lactulose ameliorates dextran sodium sulphate (DSS)-induced colitis in rats

Lactulose has been in medical use for hepatic encephalopathy for more than 4 decades. This disaccharide decreases the luminal pH in the colon and reduces the number of bacteria, resulting in inhibition of the ammonia production. The aim of the present study was to investigate the effect of lactulose on DSS-induced ulcerative colitis model. Experimental colitis was induced in male Wistar rats by 3% DSS-solution in drinking water for 7 days. Lactulose (300-1000 mg/kg) was administered p. o. twice daily for 6 days. DSS treatment induced severe colonic lesions, accompanied by decreases in body weight and colon length as well as increases in myeloperoxidase activity, thiobarbituric acid reactants and diarrhea! bloody feces. Lactulose ameliorated the colonic lesions and improved all of the investigated parameters, in a dose-dependent manner. These results demonstrated the protective effect of lactulose in this colitis model and suggested that the background of this effect may be due to the alterations of colonic microflora.