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 poly-morphonuclear 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-κBα). 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.