[Effect of exogenous pulmonary surfactant on isolated lung injury induced by ischemia-reperfusion in rats].

OBJECTIVE: To study the effect of exogenous pulmonary surfactant (PS) on the acute lung injury to ischemia-reperfusion injury. METHODS: The model of ischemia-reperfusion was established. Thirty male Sprague-Dawley rats were randomly divided into control (n = 10), I/R (n = 10), and PS (n = 10) groups. CONTROL GROUP: the isolated rat lungs were reperfused for 4 hours. I/R group: the isolated rat lungs were reperfused for 2 hours after 2 hours ischemia. PS group: exogenous pulmonary surfactant (10 mg/100 g BW) were given to the ischemic lungs through bronchus 2 hours before reperfusion. Wet to dry lung weight ratio (W/D) and pulmonary artery pressure (PAP) were checked. Immunohistochemical technique was used to determine the immune reactivity of lung tissues to endothelia nitric oxide synthase (eNOS) and surfactant protein A (SP-A). The pulmonary changes were also observed by light and electronic microscopes. RESULTS: W/D and PAP in I/R group were significantly higher than in PS group (P < 0.01). The expression of eNOS and SP-A in I/R group were significantly lower than those in PS group (P < 0.05). CONCLUSIONS: PS can significantly protect lung injury induced by ischemia-reperfusion in the isolated rat lungs. This protective effect is associated with the mechanism that the exogenous PS may reduce SP-A loss in the ischemia-reperfusion and activate the up-regulation of eNOS.