Impact of zinc deficiency on vibrio cholerae enterotoxin-stimulated water and electrolyte transport in animal model.

The effect of zinc deficiency on the function of the intestine to absorb water and electrolytes was studied in animal models, stimulated by Vibrio cholerae enterotoxin. Sprague-Dawley rats, used in the study, were divided into four groups: Zinc-deficient, ad libitum zinc-fed control, zinc weight-matched control, and zinc-deficient acutely-repleted. 14C-labelled polyethylene glycol solution was used for measuring the absorption capacity of the small intestine. Significantly lower absorption of water and sodium per cm of the intestine was observed in the zinc-deficient animals compared to the ad libitum zinc-fed control animals (p < 0.01). An improved absorption capacity was equally observed in the zinc-deficient acutely-repleted animals and ad libitum zinc-fed control group. The zinc-deficient animals showed four times greater cholera toxin-induced net secretions of water and sodium compared to the ad libitum zinc-fed group (p < 0.01), while a 40% reduction was observed in the zinc-deficient acutely-repleted group. The results suggest that zinc deficiency is associated with reduced absorption of water and electrolytes and increased secretion of the same stimulated by cholera toxin.

Influence of gentamicin on the ATPase, electrolytes lipid peroxides and histology of rat renal cortical tissues

Calcium, magnesium, sodium and potassium dependent ATPases and their corresponding cations together with the lipid peroxides and proteins were determined in renal cortical homogenate of five groups of adult male albino rats [6 animals each] from which one group was used as control and the other 4 groups were treated with a low dose of gentamicin [10 mg/-kg/D] for up to 21 days. The activity levels of the Na[+], K[+] ATPases were significantly inhibited after 15 days of treatment compared to the control whereas Mg[2]+, Ca[2]+ ATPases activity showed nonsignificant change from the control values. Both sodium and calcium cations concentrations significantly increased after 15 days in contrast to potassium and magnesium cations levels which showed a significant decrease after 15 days of treatment compared to the control values. In addition, rat renal cortical homogenates showed a significant increase in lipid peroxide levels throughout the first 15 days of gentamicin treatment. These findings were associated with histological and histochemical changes. It can be concluded that biochemical changes in renal tissue reflect the possible cellular damage. However, these changes were reversed and levels were returned to normal after 21 days of gentatmicin treatment. Therefore gentamicin should be used very cautiously using the lowest possible therapeutic dose and if it is necessary to use it, its nephrotoxic effect should be monitored in aged or critically-ill patients to detect the early laboratory and functional changes