糖皮质激素对机械通气大鼠肺组织iNOS、NO表达的影响

目的通过观察糖皮质激素对机械通气大鼠肺组织诱导型一氧化氮合酶（iNOS）及一氧化氮（NO）表达的影响,探讨糖皮质激素对呼吸机所致肺损伤（ventilator induced lung injury,VILI）的干预作用。方法 24只雄性Wistar大鼠随机分为对照组、机械通气组、地塞米松（DXM）干预组。用逆转录-聚合酶链反应（RT-PCR）法检测肺组织iNOS mRNA表达,用免疫组织化学染色法检测肺组织iNOS蛋白表达,用硝酸还原酶法测定肺组织和血浆NO含量。结果机械通气组和DXM干预组大鼠肺组织iNOS mRNA及其蛋白表达水平,以及血浆和肺组织NO含量均明显高于对照组（P〈0.01）;DXM干预组上述指标与机械通气组比较均明显降低（P〈0.01）。结论糖皮质激素可通过抑制肺组织iNOS的表达,减少NO的生成,对机械通气大鼠肺组织具有保护作用。

The Effects of Glucocorticoid on Inducible Nitric Oxide Synthase and Nitric Oxide Expressed in the Lung of Rats with Ventilation

Objective To explore the role of glucocorticoid in the course of prevention and treatment in ventilator induced lung injury（VILI） by investigating glucocorticoid effect on expression of inducible nitric oxide synthase（iNOS）and nitric oxide（NO） in lung of rats in mechanical ventilation.Methods Twenty-four health male Wistar rats were randomly divided into control group,ventilation group and dexamethasone pretreatment group（DXM group）.The expression of iNOS mRNA and protein in the pulmonary tissues were detected by RT-PCR and immunohistochemistry respectively.The concents of NO in plasma and lung tissue were detected with nitrate reductase method.Results The expression of iNOS mRNA and protein in the pulmonary tissues and the concent of NO in plasma and lung tissue in ventilation group and DXM group were significantly higher than that of control group（P〈 0.01）.Compared with ventilation group,all of above targets in DXM group were decreased significantly（P 〈0.01）.Conclusion Glucocorticoid might exert protective effects on rats ventilated lung tissue by inhibiting the expression of iNOS and the production of NO in the lung.