胸部开放伤后海水浸泡对犬肺损伤程度的影响及肺表面活性蛋白A、B的变化

目的 探讨胸部开放伤后海水浸泡对犬急性肺损伤(acute lung injury,ALI)程度的影响及肺表面活性蛋白A、B(SP-A、SP-B)的变化.方法 成年杂交犬24只,按单纯气胸、胸腔注入淡水及海水制备3种犬AU模型,观察不同时间点动脉血气、TNF-α、IL-6、肺组织及血清中SP-A、SP-B含量的变化,实验终点处死动物后行肺病理组织学检查,并用免疫组化染色观察SP-B于肺内的表达.结果 海水浸泡组及淡水浸泡组均引起低氧血症,海水组缺氧程度比淡水组严重(P<0.05).2个实验组动物血清及肺泡灌洗液(broncho-alveolar lavage fluid,BALF)中IL-8、TNF-α等炎症因子水平均较对照组增高(P<0.05),肺组织病理损伤严重,并且海水组重于淡水组.2个实验组BALF中SP-A、SP-B含量较对照组明显降低(P<0.05),血清中SP-A、SP-B含量较对照组增加(P<0.05);肺内SP-B阳性的Ⅱ型肺泡上皮细胞数量减少,其灰度值明显弱于对照组,这种改变程度在海水组及淡水组中也存在统计学差异(P<0.05).结论 胸部开放伤后海水浸泡引起的肺损伤程度重于淡水浸泡和单纯气胸.

Comparisons of pulmonary lesion and changes in surfactant proteins A and B induced by seawater and freshwater immersions after open chest injury in dogs

Objective To compare the extent of acute lung injury (ALl) and changes in surfactant proteins A (SP-A) and B (SP-B) induced by seawater and freshwater immersion following open chest injury in dogs. Methods The animal model was established by seawater and freshwater injection into the thoracic cavity after open chest injury. All the experimental animals were observed for 6 hours, during which blood gas analysis, levels of TNF-α and IL-8, contents of SP-A and SP-B in the lung and blood serum were measured at different time points. Pulmonary histopathology and SP-B immuno-histochemistry were measured after the animals were sacrificed at the end of the experiment. Results Both seawater immersion and freshwater immersion could induce hypoxemia, with the extent of hypoxemia for the seawater immersion group (SG) being obviously much severer than that of the freshwater immersion group (FG) (P < 0.05). The levels of IL-8 and TNF-α in blood serum and BALF of both experimental groups were significantly higher than those of the control group (CG) (P<0.05). Pulmonary pathological lesion was noted in both SG and FG, with that of SG being severer than that of FG. The levels of SP-A and SP-B in BALF in SG and FG all decreased significantly(P <0.05) ,while the levels of SP-A and SP-B in blood serum increased gradually (P < 0.05). Type Ⅱ alveolarepithelial cells with SP-B positive in the lung decreased in both experimental groups, with grey scale values being significantly lower than that of CG. And significant deviation was observed between SG and FG (P <0.05). Conclusions Pulmonary lesion induced by seawater immersion after open chest injury was severer than that induced by freshwater immersion.