Blood transfusions have been shown in the past to compromise wound healing in experimental models of colonic anastomosis. Transforming growth factor beta (TGFbeta) has been proposed to play a major role in the process of colonic wound healing, and its expression is believed to be modulated by interleukin-2 (IL2). According to an earlier report, the postoperative administration of the histamine receptor-2 antagonist ranitidine increases the blood levels of soluble IL2 receptor in humans undergoing abdominal surgery and could thus affect molecular determinants of colonic anastomosis. In this study we examined the effect of blood transfusions, with and without ranitidine administration, on the gene expression of TGFbeta(1) and the specificity-conveying alpha subunit of the receptor for IL2, in rat perianastomotic tissue. Analysis of gene expression by semiquantitative RT-PCR revealed a tendency for downregulation of both genes, albeit in a statistically nonsignificant manner. This effect was not prevented by the postoperative administration of ranitidine. On the other hand, there appears to be a significant correlation between expression of TGFbeta(1) and that of IL2 receptor alpha subunit, irrespective of treatment.