[Study on the experimental ulcerative colitis (UC) model induced by dextran sulfate sodium (DSS) in rats (2)].

We have confirmed that symptoms in the experimental UC model in rats induced by ingesting 3% DSS were similar to those of the human UC. In this study, we investigated the procedure for assessing the therapeutic effect of SASP and PSL. (1) The UC model was produced by giving rats drinking water containing 3% DSS, and animals were selected when bloody stool was observed in more than 90% of the animals. (2) Procedure for selection of rats: (a) presence of bloody stool for more than two consecutive days, (b) concentration of hemoglobin at more than 10 g/dl and (c) B.W. on the day of selection was not decreased more than 20 g against the B.W. on the day before the selection. (3) After selection, various concentrations of DSS (1-3%) were given to rats for 14 days. SASP and PSL were administered to the UC model once a day for 14 and 7 days, respectively, with the animals given drinking water containing 1% DSS after the selection. SASP (100 mg/kg, p.o.) and PSL (1 mg/kg, i.r.) significantly inhibited the formation of erosion by 56.1 and 47.5%, respectively. In conclusion, this procedure used herein seems to be useful for assessing the therapeutic effect of a drug for human UC.