Cellular dynamics in the jejunum of essential fatty acid deficient mice

The population dynamics of the jejunal epithelium of mice maintained on a semi‐synthetic diet deficient in the essential fatty acids (EFA) has been investigated. Colchicine was employed to collect mitotic figures for the determination of mitotic indices. Twenty‐five crypts in longitudinal section were counted per animal and the mean mitotic index computed as the number of mitoses per total number of crypt cells. EFA‐deficient animals had a mean mitotic index of 36.56 as compared with 26.51 and 16.74 for the linoleic acid‐supplemented and chow‐fed control animals, respectively. Counts of the number of epithelial cells on one side of a villus and crypt indicated that the height of the villi, but not the crypts, of the EFA‐deficient animals was significantly lower than either control group. In the EFA‐deficient animals the mean percentage of villi having extrusion zones exceeded that of both control groups. Radioautography demonstrated that 36 hours after injection of tritiated thymidine the majority of villi in the EFA‐deficient animals were labeled at their tips, whereas in control samples label was restricted to the lower one‐half to three‐fourths of the villus. Thus, EFA‐deficiency induces increased rates of mitosis, migration and sloughing, resulting in alterations in villous architecture.