高氧致慢性肺疾病新生鼠肺组织水通道蛋白1、5的表达及其调控作用的研究

Changes of AQP1 and AQP5 in the lung tissues under hyperoxia induced chronic lung disease and their contribution in lung injury in newborn rats

目的水通道蛋白(AQP)是新近发现的一组与水通透性有关的细胞膜转运蛋白,该文旨在探讨高氧损伤状态下,肺组织内AQP1、AQP5的动态变化规律及其调控作用。方法新生鼠160只,依据吸氧浓度(FiO2)分为实验组1(FiO2800 mL/L)、实验组2(FiO2600 mL/L)、实验组3 FiO2400 mL/L)和空气对照组(FiO2210 mL/L)。每组分别于实验后1、3、5、7和14 d行AQP1、AQP5、细胞外信号调节激酶(ER K)的免疫组织化学检测,同时行AQP1、AQP5 Western blotting印迹检测。结果随吸氧浓度及暴露时间的增加,实验组AQP1第3天表达开始降低,第5天和第7天明显降低(P<0.05),第14天有所恢复。实验组AQP5表达低于对照组,第1天和第3天呈稍高表达,以后随日龄增加逐渐降低(P<0.05)。总趋势上AQP1、AQP5的表达在实验组3、实验组2、实验组1依次降低;肺组织ERK1/2表达对照组维持在较低的水平,实验组ERK1/2表达于第7天和第14天均明显高于对照组。ER K1/2变化与AQP1表达呈正相关(r=0.625,P<0.001;r=0.572,P<0.001;r=0.798,P<0.001;r=0.645,P<0.001)。结论 AQP1、AQP5在高氧肺损伤时表达降低,高氧肺损伤中AQP合成、分泌信号可能是ERK途径转导的。

[Objective] Aquaporin （AQP） is a group of cell-membrane transporting proteins. The study was designed to investigate the changes of AQP1 and AQP5 in the lung tissues under byperoxia and their contribution in lung injury. [Methods] One hundred and sixty newborn rats were randomized into different oxygen concentrations exposure： FiO2 800 mL/L （Experimental group 1）, FiO2 600 mL/L （Experimental group 2）, FiO2 400 mL/L （Experimental group 3） and FiO2 210 mL/L （Air control group）. Rats were sacrificed atl, 3, 5, 7 and 14 days after the beginning of experiment （8 rats each time point）. The expressions of AQP1, AQP5 and ERK were examined by immunohistochemistry. The expressions of AQP1 and AQP5 were also observed by Western Blot. [Results] In the three experiment groups increased significantly and the increased extent was positively related to the duration and the oxygen concentration of hyperoxia-exposure. The expression of AQP1 in the experimental groups began to decrease at the 3rd day and significant differences were found at the 5th and the 7th days after hyperoxia-exposure compared with that in the Air control group （P〈0.05）. The AQP1 expression was restored somewhat at the 14th day after hyperoxia-exposure, but it was still lower in the Experimental groups 1 and 2 than that in the Air control group （P〈0.05）. The expression of AQP5 in the experimental groups were reduced compared With that in the Air control group 3 days after hyperoxia-exposure and the decrease of AQP5 expression was associated with duration of hyperoxia-exposure. The comparison among three experimental groups showed that the decrease of AQP1 and AQP5 expressions was associated with the concentration of hyperoxia-exposure. ERK expression in lung tissue of control group remained in relatively low levels, but significantly higher levels of ERK expression could be detected in experimental groups at 7th and 14th day. The expression of AQP1 and AQP5 in the lung tissue was positively related to the ex- pression of ERK protein. [Conclusion] The expressions of AQP1 and AQP5 decreased in hyperoxia-induced lung injury and the signal for the synthesis and secretion of AQPs might be transmitted through ERK pathway （r=0.625, P〈0.001; r=0.572, P〈0.001; r=0.798, P〈0.001; r=0.645, P〈0.001）.