EN
The effects of histidine and ketotifen in separate and combined treatments were histopathologically investigated in a rat model of acute colitis. Acute colitis was induced by the intracolonic instillation of 1 ml of 4% acetic acid. Histopathological changes of the colon were scored based on the severity of inflammatory and degenerative changes. Compared to the intact group, there was congestion, oedema, haemorrhages, leukocyte infiltration, and degeneration in the acetic-acid-induced colitis group. In the separate treatments with intraperitoneal (i.p.) injection of histidine at doses of 40 and 200 mg/kg and with oral administration (p.o.) of ketotifen (0.4 and 2 mg/kg) applied 1 and 24 h after induction of colitis, the inflammatory and degenerative changes were significantly (P<0.05) reduced. In combined treatment, co-administration of histidine (200 mg/kg, i.p.) with ketotifen (2 mg/kg, p.o.) produced a more documented response in comparison with the histidine (200 mg/kg, i.p.) and ketotifen (2 mg/kg, p.o.) used alone. The results suggested that intracolonic instillation of acetic acid produced acute colitis. Both histidine and ketotifen exerted anti-inflammatory effects on acetic-acid-induced colitis. In addition, ketotifen potentiated the anti-inflammatory effect of histidine.