Quantitative study of apoptosis in normal rat gastroduodenal mucosa.

The occurrence of apoptosis in the normal gastrointestinal mucosa has been given little consideration until now, although the phenomenon may be of interest in the light of recent hypotheses about its role in physiological cell renewal. In the present study, a quantitative evaluation conducted on normal gastric and duodenal mucosa of young rats has shown that apoptosis is a rare but constant phenomenon: 1.4 +/- 1.1 (mean +/- 1 s.d.) apoptotic bodies were observed within the surface epithelium of single gastric pits and 3 +/- 1 in duodenal villi. In both situations, the apoptosis showed a preferential localization in the juxtaluminal segments of the epithelium. This phenomenon appears distinct from passive exfoliation of mucosal cells and, as an expression of 'programmed cell death', it is likely to contribute to the normal intestinal epithelial cell turnover.