Effect of zinc deficiency and wounding on DNA synthesis in rat skin

Enhancement of re-epithelialization with topical zinc oxide in porcine partial-thickness wounds

We investigated the effect of locally applied zinc on the healing of partial-thickness skin wounds in the domestic pig using two zinc compounds (zinc oxide and zinc sulfate) in two different vehicles (a gauze compress and a collagen sponge). The rate of re-epithelialization was determined morphometrically 48 and 64 hr after infliction of standardized square wounds (4.8 cm2 and 400-microns deep) with an electrokeratome. Zinc oxide in gauze significantly (P less than 0.05) increased re-epithelialization of the wounds (33% more epithelialized than control wounds after 64 hr) and in collagen sponge (76% more epithelialized than control wounds after 64 hr). Zinc sulfate had no such stimulatory effect at any dosage or vehicle used. Our results show that topical zinc oxide enhances re-epithelialization of partial-thickness wounds in nutritionally balanced pigs and that the mode of delivery of zinc is probably critical for achieving the beneficial healing effect of zinc.

The effects of feeding a zinc-deficient diet on taste acuity and tongue epithelium in rats

Taste preferences, fluid intake and histology of tongue epithelium were studied in rats fed a zinc-deficient diet and in pair-fed controls. The results of two-bottle preference tests demonstrated that zinc-deficient rats exhibited significantly increased preferences for 1.5 X 10(-1) M HCL and 1.28 X 10(-6) M quinine sulfate as well as a significant increase in relative fluid volume intake. Histologic examination of the tongue epithelium of the zinc-deficient rats showed a hypercellular prickle cell layer and a marked parakeratosis. The fungiform papillae of the zinc-deficient rats exhibited acanthosis and mild parakeratosis. However, the pore region of the taste buds did not seem to be covered by the parakeratotic epithelium. The results suggest that the impaired taste observed in zinc-deficient rats may not be related to blockage of tastants from the pore region.

The enhancement by dietary zinc deficiency of the susceptibility of the rat duodenum to colchicine

1. The incidence of colchicine-induced lesions in the germinal epithelium oof the rat duodenum was studied in young rats in an early stage of zinc deficiency and in their pair-fed controls. At both dose levels of colchicine used, a marked increase in the amount of cell damage was observed in the duodenum of Zn-deficient rats as compared with the pair-fed, control (Zn-supplemented) rats. 2. No statistical interaction between Zn and colchicine was demonstrable, and no lesions were found in the duodenum of animals that had not been treated with colchicine. 3. The results are discussed in relation to the effects of Zn deficiency in animals and the possible involvement of Zn in the maintenance of the integrity of microtubular structures.

Chromosomal abnormalities in maternal and fetal tissues of magnesium- or zinc-deficient rats

The effect of dietary deficiency during pregnancy of zinc or magnesium on maternal and fetal chromosomes was studied. Pregnant rats were given a zinc-deficient or a magnesium-deficient diet from the beginning of pregnancy and maternal bone marrow and fetal liver were removed on day 19 of gestation. Chromosome spreads were prepared and metaphases examined for abnormalities. Both magnesium- and zinc-deficient maternal bone-marrow and fetal liver cells showed significantly more chromosomal abnormalities than did those of controls. The chromosomal aberrations occurring in highest incidence in magnesium-deficient animals were terminal deletions and fragments. A higher than normal incidence of "stickiness" was also observed in cells from magnesium-deficient animals. In zinc-deficient animals, on the other hand, the chromosomal aberrations with the highest incidence were gaps and terminal deletions.