0.28MPa酸素暴露により生じた亜鉛欠乏ラットの肺組織障害

抄録

In recent years, it has been suggested that Zinc deficiency causes alteration in the biological defense system. To examine the effects of hyperbaric oxygen therapy (HBO) on the lung tissues of zinc deficiency models, zinc deficient rats were investigated morphological changes and the expression of TNF-α, Cu/Zn SOD, ED₁ and iNOS in the lung tissues by immunohistochemically after exposure to high pressure using pure oxygen. In the present study, two special diets were prepared ; a zinc deficient diet and a standard diet (0.05 % Zn). Seven weeks old SD strain rats were fed either on a Zn deficient (Zn-D, n=12) or a standard diets (Control, n=12) for 6 weeks. Six of ZnD and 6 of Control were exposed to 0.28 MPa using pure oxygen for 60 minutes in a hyperbaric chamber (ZnD-O₂ and Control-O₂). After decompression to surface, histopathological and immunohistochemical examination of lung tissues of rats in the 4 groups were carried out. Mild pathological changes such as congestion, destruction of alveoli and the appearance of inflammatory cells were seen in the ZnD-O₂. Expression of ED₁ and iNOS decreased in ZnD-O₂. Changes in the expression of TNF-a and Cu/Zn SOD did not seen in ZnD, Control-O₂, ZnD-O₂. These findings suggest that zinc deficiency reduces the threshold level of oxygen toxicity in lung tissues. These results also suggest that hyperbaric oxygen therapy causes the lung damage in patients under zinc deficiency condition. Moreover, the results in immunohistochemical study after oxygen exposure indicate that zinc deficiency causes alteration in the normal biological defense system.