Effect of short-term dietary administration of butylated hydroxyanisole on cell kinetic parameters in rat gastro-intestinal tract, assessed by immunocytochemistry and flow cytometry.

Groups of five male Wistar rats weighing 306 +/- 17 g were fed a diet containing 2% 2-(3)-tert-butyl-4-hydroxyanisole (BHA) or basal diet (control group) for 2 weeks. Subsequently, rats received an i.p. injection of 25 mg/kg bromodeoxyuridine (BrdU), a thymidine analogue, and were killed after 4 h. The gastro-intestinal tract was removed and fixed in 70% ethanol. After pepsin digestion of the fixed tissues, labelled cell nuclei were visualized by means of a monoclonal anti-BrdU antibody technique. Cell kinetic parameters were determined by means of bivariate BrdU/DNA analysis using flow cytometry. Mean labelling index and potential doubling time of forestomach cells were significantly increased (P less than 0.002) in the 2% BHA group as compared to control rats. Cell kinetic parameters in other organs--glandular stomach, ileum, caecum and colon--were not affected by short-term consumption of BHA.