外源性肺泡表面活性物质对大鼠呼吸机相关性肺损伤的保护作用

Protective Effect of Exogenous Pulmonary Surfactant on Ventilation-induced Lung Injury in Rats

目的探讨气管注入肺泡表面活性物质(PS)对大鼠呼吸机相关性肺损伤(VILI)的保护作用及机制。方法将40只Wistar大鼠采用区组法随机分为对照组、高潮气量组(HV组)、VILI组和PS组4组,每组各10只。对照组未行机械通气,其余3组容量控制通气,PS组同时经气管内插管注入猪PS100mg/kg。监测心率、平均动脉压(MAP)、血气分析、肺湿/干重比(W/D)和支气管肺泡灌洗液(BALF)中白细胞计数,测定肺组织核因子-κB(NF-κB)活性和BALF中及血清白细胞介素-8(IL-8)浓度,并观察大体及光学显微镜下肺组织损伤的改变。结果损伤性机械通气后大鼠MAP及氧合指数(PaO2/FiO2)显著降低,而肺组织NF-κB活性和W/D显著增高。PS组与VILI组相比,MAP、PaO2/FiO2、肺组织NF-κB活性、BALF中白细胞计数、BALF及血清中IL-8浓度均有统计学意义(P<0.05)。组织学检查显示PS组较VILI组病变明显减轻。结论经气管注入PS可抑制VILI大鼠NF-κB基因表达,对VILI有保护作用。

Objective To observe the effects of exogenous pulmonary surfactant (PS) on ventilation-induced lung injury (VILI) in rats, and to investigate its possible mechanisms. Methods A total of 40 Wistar rats were divided into 4 groups with randomized blocks method: control group, high tidal volume (HV) group, VILI group, and PS group, with 10 rats in each group. The control group was subjected to identical surgical procedure but was never ventilated. After 30 min of mechanical ventilation (MV) with Vt 45 ml/kg, the rats in HV group were killed immediately; rats in the VILI group were continually ventilated for up to 150 min with Vt 16 ml/kg; in the PS group, 100 mg/kg of PS administered intratracheally and with the same settings as VILI group. Mean artery pressure (MAP), blood gas analysis, lung wet to dry weight ratios (W/D), thorax-lung compliance, and cell counts in bronchoalveolar lavage fluid (BALF) were determined. Nuclear factor-κB(NF-κB) activity in lungs was measured by enzyme-linked immunosorbent assay (ELISA), interleukin-8(IL-8) in serum and BALF was determined by radioimmunoassay (RIA). Pathological examination of the lung was performed. Results Injurious ventilation significantly decreased MAP and PaO_2/FiO_2, but increased NF-κB activity and W/D. MAP and PaO_2/FiO_2 improved, but NF-κB activity, IL-8 in serum and BALF, and cell counts in BALF reduced significantly in PS group compared with those in VILI group. Histological studies showed reduced pulmonary edema and atelectasis in the PS group. Conclusion PS administered intratracheally can suppress the increased activity of NF-κB induced by VILI, exogenous PS can be used to treat VILI.