急性呼吸窘迫综合征大鼠肠黏膜屏障功能的研究

An experimental study on the gut mucosal barrier in rats with acute respiratory distress syndrome

目的研究ARDS大鼠肠黏膜屏障功能的变化。方法雄性SD大鼠40只随机分为实验组(30只)及对照组(10只)。实验组股静脉注射油酸建立大鼠ARDS模型,按照注射油酸后不同时间,以30 min、2 h及4 h为时限,再随机分为3组,分别取血测定血浆D-乳酸浓度、内毒素水平、二胺氧化酶(DAO)活性,观察小肠组织病理学变化。结果实验组注射油酸30 min后,DAO活性较对照组显著升高(P<0.01);注射油酸2 h后,血浆D-乳酸和内毒素浓度、DAO活性均较对照组显著升高(P均<0.05),并随着时间延长呈进行性升高趋势。注射油酸2 h后大鼠小肠绒毛间质内充血、水肿,中性粒细胞、嗜酸粒细胞和淋巴细胞浸润,4 h后小肠绒毛顶部上皮细胞脱落、坏死、变性、糜烂,黏膜内大量中性粒细胞及淋巴细胞浸润。结论在油酸所致ARDS过程中大鼠肠黏膜通透性增加,肠黏膜屏障功能降低。

Objective To observe barrier function changes of gut mucosa in rats with acute respiratory distress syndrome（ARDS）. Methods Forty SD rats were randomized to an experiment group （n =30） and a control group（ n = 10）. Oleic acid was injected via vena femoralis to establish ARDS rat model. Subgroups in the experiment group were randomly divided by time 30 min, 2 h, 4 h interval after injection （ n = 10 in each subgroup）. Concentration of D-lactate and endotoxin and activity of diamine oxidase in blood plasma were measured. Histopathological changes of small intestine were observed under light microscope. Results Compared with the control group, the activation of diamine oxidase in the experiment group was higher after 30 min of injection （P 〈 0. 01 ）. Concentration of D-lactate, the activity of diamine oxidase and endotoxin level in the experiment group were all elevated after 2 hours of injection（ all P 〈 0. 05 ）, and further elevated after 4 hours. In the rats＇ villous interstitial after 2 hours of the injection, there were edema, hyperemia, and infiltration of neutrophils, eosinophils and lymphocytes. After 4 hours of the injection, the villous epithelium showed desquamation, necrosis, denaturalization and erosion, associated with infiltration of lymphocytes and neutrophils in the mucosa. Conclusion In oleic acid-induced ARDS, permeability of gut mucosa increases and gut barrier is dysfunctional.