EXPERIMENTAL COLITIS INDUCED BY DEXTRAN SULFATE IN NORMAL AND GERM-FREE MICE

Experimental colitis in mice, induced by administration of 2.5 or 5 per cent dextran sodium sulphate (DSS; Mwt = 40 kDa, S = 16 per cent) in the drinking water, was characterised and optimised. The degree of colitis was evaluated after 7-10 d of acute exposure (5 per cent), after continuous supply for 22, 27 and 35 d (2.5 per cent), and after two and three 7 d cycles with DSS (5 per cent) in water. The colitis was manifested by typical clinical symptoms such as weight loss, rectal bleeding and diarrhoea. Macroscopically a shortening of the colon was observed and histologically epithelial cell damage, crypt loss and infiltration of mononuclear cells was verified. A stable subacute colitis with maintained diarrhoea (wet/dry weight of the faeces) and shortening of the colon, but no mortality or gross rectal bleeding was induced within 3 wk either by continuous supply of 2.5 per cent or by two 7 d periods of exposure to 5 per cent DSS. The development of colitis in germfree animals excludes a critical role of the intestinal microbiota for the induction of colitis by DSS.