STUDIES ON THE EFFECT OF SURAMIN ON CELL-PROLIFERATION OF EPITHELIAL TISSUE RENEWAL IN THE MOUSE

The effect of a three-week treatment regimen with suramin (30, 60 or 9 0 mg/kg body weight) on the cell proliferation of small intestinal cry pts and dorsal epidermis of the nude mouse was studied using standard auto-radiographic methods after in vivo pulse labeling with H-3-thymid ine. Suramin was slightly toxic to the animals in a dose-dependent man ner (p<0.01) as measured by the decrease of the rate of weight gain of the treated animals. In the small intestine suramin treatment led to crypt shrinkage (factor: about 70-80%; p<0.05) mainly by increasing th e rate of cell loss out of the crypt epithelium (p<0.05) and to a less er degree by inhibiting the proliferation of crypt cells. However, thi s suramin treatment scheme did not significantly affect the H-3-thymid ine labeling index and the mitotic index of the basal cell layer of th e epidermis. The present findings indicate that suramin can be used to approach the problem of differential homeostatic reactions of epithel ial tissue renewal in vivo.