Zinc-deficient diet aggravates ventilation-induced lung injury in rats

We investigated the effects of zinc deficiency on acute lung injury (ALI) induced by mechanical ventilation. Male Sprague-Dawley rats were fed with a zinc-deficient or zinc-proficient diet for 4 weeks, and then received mechanical ventilation at normal frequency and pressure for 30 min. Total protein, cell count, the number of polymorphonuclear neutrophil (PMN) in the bronchoalveolar lavage (BAL), and vascular endothelial growth factor (VEGF) expression in the lung were determined. Activation of nuclear factor-κB (NF-κB) was detected by examining the phosphorylation of NF-κB (pNF-κB p65) and the expression of inhibitor of NF-κB (pI-kBα). Compared to the controls, total cell count and the number of PMNs were significantly increased to 160% and 140%, respectively, in zinc-deficient rats treated with ventilation. Activation of NF-κB was significantly increased and VEGF was also increased to three-folds. Zinc deficiency aggravated the inflammatory response in rats and was associated with the overexpression of VEGF in response to mechanical ventilation. Zinc supplementation may be beneficial to zinc-deficient patients during mechanical ventilation.