Crypt cell production rate in the small intestine of the zinc-supplemented mouse

Zinc is a trace element which is necessary in the body and the daily requirement is usually provided mainly through food intake. The effects of zinc deficiency are multisystemic and in the gastrointestinal tract include ulceration and inflammation. Many of these effects in the mammalian small intestine are reversible by zinc replenishment in a manner that is thought to be linked to the effect of this element on intestinal mucosal cell kinetics. However, the effects of continued replenishment (supplementation) have not been closely examined. This study examined the effects of zinc supplementation on gut crypt cell production in zinc-replete animals. Fifteen CD-1 mice were given zinc sulphate (0.3 mmol/l) in tap water while a second (control) group of 15 mice received only tap water. After 14 days, the small intestine was removed, measured and divided into four equal lengths and then sampled at the midpoint of each of the resulting four segments. Whole crypt numbers and crypt cell production rate were determined for each intestinal site for both groups of mice. While crypt dimensions and crypt numbers in zinc-fed mice showed no significant change from control levels, the crypt cell production in zinc-fed mice was significantly increased and duration of mitosis reduced in the third (distal) intestinal segment when compared to values from control mice. These findings show that the addition of subtoxic quantities of zinc to diet in zinc-replete animals enhances cell production and indicate that the reversal of zinc deficiency-induced gut damage following dietary zinc replenishment may be due to a direct effect on cell kinetics.