海水淹溺型急性肺损伤兔血管内皮生长因子及其受体的表达

Expression of vascular endothelial growth factor and its soluble receptor in seawater drowning-induced acute lung injury

目的探讨海水淹溺型急性肺损伤(SWD-ALI)后血清及组织血管内皮生长因子(VEGF)及其可溶性受体-1(sVEGFR-1)的表达变化及意义。方法健康成年新西兰兔28只,采用随机数字法均分为对照组和模型组(制作SWD-ALI模型),分别用于3h和6h时间点(每组7只)的观察。分别检测各组动物的肺微血管通透指数、肺湿/干重比和肺组织病理学评分;ELISA法检测血清、肺泡灌洗液(BALF)及肺组织的VEGF及sVEGFR-1表达,RTPCR法检测肺组织mRNA表达;免疫组化法检测VEGF在肺组织的分布。结果海水淹溺后,肺组织湿/干重比、肺微血管通透指数均增高,肺组织病理损伤重,6h时点肺组织湿/干重比略低于3h,而肺组织病理学积分仍高于3h。血清中VEGF和sVEGFR-1水平均明显升高,并与损伤时间(r=0.837,r=0.761,P<0.01)和病理积分呈正相关(r=0.796,r=0.839,P<0.01)。VEGF和sVEGFR-1在肺组织及BALF中的表达均明显减低,两者mRNA的表达也明显减低,6h时有所回升。免疫组化提示VEGF在对照组大量表达,分布均匀,淹溺后表达明显减少,分布不均。结论SWD-ALI时,VEGF和sVEGFR-1表达异常,两者变化规律一致,其水平与肺损伤的程度相关。

Objective To explore the expression of vascular endothelial growth factor （VEGF） and its soluble receptor （sVEGFR-1） in serum and lung tissue in seawater drowning-induced acute lung injury （SWD-ALI） in rabbits. Methods Twenty-eight healthy New Zealand rabbits were randomly allocated by using a random number table into 2 groups （n=14）： control group （CG） and seawater-drowning group （SG, inhalation of 2ml/kg of seawater）. Observation was made in seven rabbits in each group at 3h, and the others at 6h. Permea- bility index, lung wet/dry ratio （W/D） and pulmonary pathologic score were evaluated. VEGF and sVEGFR-1 expressions in serum, branchoalveolar lavage fluid （BALF） and lung tissues were detected by ELISA at different time points during the experiment. Moreover, the mRNA expression was determined by real-time PCR and the VEGF distribution in pulmonary tissues was displayed by immunohistochemistry. Results Compared with the control group, lung W/D and permeability index increased in SWD-ALI. The lung W/D was higher, while pathologic score was lower in 3h time point than in 6h time point. The levels of VEGF and sVEGFR-1 increased in serum, and was positively correlated with the injured time （r=0. 837, r=0. 761, P〈0. 01） and pathologic scores （r=0. 796, r=0. 839, P〈0. 01）. The protein and mRNA expressions of VEGF and sVEGFR-1 decreased significantly in lung tissue and BALF, and went up again at 6h time point. Immunohistochemistry indicated that VEGF expression was abtmdant and well-distributed in control group, while was obviously decreased and scattered in SG group. Conclusion Seawater drowning may result in abnormal expressions of the proteins and mRNAs of VEGF and sVEGFR-1, and the expressions of both VEGF and sVEGFR-1 show uniform fluctuation, which is positively correlated with the severity of injury.