A topological study of the epithelial cell proliferation in the ascending colon of the mouse.

Epithelial cell proliferation has been studied from a topological point of view, in the ascending colon of the mouse. The ascending colon was investigated because it offered the possibility of studying distinct mucosal sites according to whether they are situated on folds or away from the folds. Consequently fold top areas (FTA), fold side areas (FSA), flat mucosa areas (OFA) have been studied individually. To determine mitotic activity, we have used the technique of arrested metaphases by a stathmokinetic agent. The estimate of the epithelial compartment size has been undertaken according to a stereological methodology. The topographical study consisted of three parts: a reproduction of the mitotic density distribution on a colonic area of significant importance; a topographical stathmokinetic study; a reconstitution of the profile of mitotic densities all along a mean model mucosal fold. The findings obtained from these different approaches present evidence that the distribution of mitotic activity within the colon is not homogeneous, that the relief of the mucosa is a factor occurring in proliferative cellular activity. The highest mitotic densities are situated on FTA, and the lowest ones on OFA. Mitotic density increases on the fold, in the terminal fifth of its length.