人胃液吸入诱导大鼠肺通透性及肺组织学的变化

Changes of respiratory permeability and pathology of lungs after lung aspiration of human gastric juice in rats

目的:观察大鼠吸入人自然空腹胃液或稀盐酸后肺通透性及肺组织学的变化。方法:将27只雄性SD大鼠平均分成3组:A组(n=9)为空白对照组;B(n=9)组为盐酸组(pH=2.3);C组(n=9)为人自然空腹胃液组(pH=2.3)。A组只进行麻醉和气管切开手术,B组、C组均以0.8ml/kg的容量经气管导管将盐酸液或胃液注入鼠肺,监测基础状态、吸入后30min、1h、2h、3h及4h的呼吸末二氧化碳分压(PetCO2)和呼吸频率(RR)。至4h处死动物,测定右中叶肺湿干重比(W/D),并行左肺灌洗,测定肺泡灌洗液(BALF)中肺通透指数(BLAF总蛋白/血清蛋白),观察肺病理学改变。结果:三组PetCO2在各时间点变化无显著性差异;B、C组吸入后RR增快(P<0.05)。与A组比较,B组、C组的肺W/D和BALF中蛋白含量均增加(P<0.05),C组肺通透指数显著增加(P<0.05)。光镜肺组织学可见A组无明显损伤或损伤轻微,C组损伤最严重,可见肺泡壁破坏严重,弥漫性充血水肿,肺间质、肺泡水肿,肺泡间隔增宽,大部分肺泡萎陷,肺内大量多形核中性粒细胞(PMN)浸润。B组肺组织损伤程度介于A组和B组之间。结论:自然空腹胃液(pH=2.3)吸入可导致肺通透性增加、非心源性肺水肿及严重肺组织病理损伤。这种肺损伤比单纯吸入盐酸(pH=2.3)的肺损伤程度更严重。

Objective：To observe the role of human gastric juice in permeability and pathology of aspiration lung injury. Methods ：Twenty seven male rats were anesthetized and randomly divided into three groups of 9 each：in group A only incision of trachea; in group B HCL （pH=2.3） was instilled into the lungs; in group C natural gastric juice （pH=2.3）.The volume of fluid instilled into the lungs was 0.8ml/kg into group B and group C. PetCO2 and respiratory rate was measured before and 30min,1h,2h,3h and 4h after aspiration. The animals were killed 4h after aspiration. The wet/dry weight ratio of right intermediate lobe and the levels of total protein and serumal protein of bronchoalveolar lavage fluid （BALF） from left lung were measured. The pathological changes of right lungs were observed 4 hours after aspiration. Results：Respiratory rate increased dramatically in group B and C after aspiration（P0.05）,but PetCO2 remained in normal lever （P0.05）. W/D ratio and levels of total protein were significantly higher in group B and group C than those in group A （P0.05）. Compared with group A,lung permeability index was dramatically increased in group C （P0.05）.Light microscope examination：In group A there was no significant or slightly change,with a few neutrophils. In group C damages were most serious finding extensive morphologic lung damage：hemorrhage,edema,infiltration of PMN,proteinaceous exudates. Degree of injury in group B was less than that in group C. Conclusion：Aspiration of gastric juice（pH=2.3）can increase lung permeability,and cause non-Cardiogenic lung edema and serious lung pathologic injury. The damage after aspirating gastric juice was more serious than that of HCL（pH=2.3）.