• calpain
• calpain inhibitor I
• cyclooxygenase
• nitric oxide
• inflammatory bowel disease
• rat

We read with interest the paper by Cuzzocrea et al in which they demonstrated the marked beneficial effects of calpain inhibitor I on colonic inflammation induced by dinitrobenzene sulphonic acid (DNBS) in the rat. On the basis of their findings, they suggest that calpain inhibitor I treatment may be useful in inflammatory bowel disease (Gut 2001;48:478–88).

It is debatable whether a model that is associated with a mortality of 40% and 80% at two and six days, respectively, after induction of colitis has any relevance to human disease. The different numbers given in the text (seven animals per group) and figure 4 (10 rats in each group) further confuse interpretation of the mortality data. The authors have apparently taken their methods for induction of colitis from previously published work although the paper that they quote described induction of ileitis (not colitis) in guinea pigs.¹ We also use a rat model of colitis and would suggest that intrarectal administration of 20 mg trinitrobenzene sulphonic acid in 40% ethanol is associated with a mortality of less than 8% at seven days. …