Effect of concomitant polyethylene glycol and celecoxib on colonic aberrant crypt foci and tumors in F344 rats.

We investigated whether celecoxib augments the protective effect of polyethylene glycol (PEG) on colonic aberrant crypt foci (ACF) and tumor formation in F344 rats treated with azoxymethane (AOM). Three groups of rats received AOM: I (AOM alone), II (PEG), and III (PEG/celecoxib). PEG reduced the mean number of total ACF per colon from 190 to 141 (P < 0.05; 26% reduction) and > or = 4-crypt ACF from 95 to 58 (P < 0.01; 39%). Group III rats had a greater proportion of their ACF distally; whereas transverse colon ACF were reduced approximately 50%, distal ACF were reduced by only approximately 8% (P < 0.05). Of 13 large bowel tumors, 8 were in Group I, 4 in Group II, and 1 in Group III rats (P = 0.02). Thus in AOM-treated rats celecoxib appeared to enhance the PEG-induced reduction in colonic tumor formation, and in transverse but not distal or whole-colon ACF.