Apoptotic process in the monkey small intestinal epithelium: I. association with glutathione level and its efflux

Abstract

The apoptotic process in the normal gastrointestinal mucosa is of interest due to its possible role in physiological cell renewal. The aim of this study was to identify the apoptotic process in the monkey small intestine and the association of glutathione level and its efflux in this process. Monkey small intestinal epithelial cells were separated in to different fractions consisting of villus, middle and crypt cells. Apoptosis was identified by DNA ladder pattern and Hoechst staining. The level of glutathione, its efflux and the enzymes involved in its metabolism were quantitated in these fractions. Apoptotic cells were identified predominantly in the villus tip cell fractions by both DNA ladder pattern and Hoechst dye staining. Glutathione level was 7 fold higher in the crypt cells as compared to villus tip cells the middle cells showing a gradual decrease. A similar pattern was seen in mitochondrial content of glutathione. As the cells mature from crypt to villus, there is increased efflux of GSH, which may be responsible for the decreased level of GSH in apoptotic villus cells. In the monkey small intestine, apoptotic cells are seen in the villus tip fractions and the glutathione level and its efflux may play a role in this process.