Exacerbation of acetic acid ulcer induced by non-steroidal anti-inflammatory drugs in rats

The influences of non-steroidal anti-inflammatory drugs (NSAID) on acetic acid ulcer were examined in rats. NSAID used in this study were aspirin (ASP, 200 mg/kg), indomethacin (IND, 2 mg/kg) and phenylbutazone (PHE, 100 mg/kg). These NSAID were administered consecutively for 5 days once a day at the early stage of the ulcer. Eleven days after the ulceration, suppression of the healing was observed in rats treated with all of the NSAID. In the rats treated with either ASP or IND, a delay of healing was observed not only 11 days after ulceration, but also 16 days after ulceration. The ulcer index in rats treated with either ASP or IND 16 days after ulceration was greater than that at 11 days after ulceration. Further studies were performed regarding the progressive change of mucosal hexosamine content, gastric secretion and gastric emptying during the healing process of the ulcer. It was found that the increase of hexosamine plays an important role in the healing of the ulcer and that a durable fall in hexosamine content was related to the remarkable exacerbation of ulcer induced by either ASP or IND. Hypersecretion, back diffusion of hydrogen ion or a delay of gastric emptying cannot be regarded as a cause of the exacerbation of the ulcer.