细胞因子和水钠通道蛋白在急性肾损伤致肺损伤中的作用

 
 
The roles of cytokines and water sodium channel proteins in acute kidney injury-induced acute lung injury rats MA Tao， LIU Zhi.Department of Emergency Medicne， The First Hospital of China Medical University，Shenyang 110001，China
Corresponding author： LIU Zhi， Email： liuzhicmu2004@yahoo.com.cn
【Abstract】Objective To observe the physiopathologic changes of lung in rats with acute ischemic kidney injury， and to study the roles of cytokine，epithelial sodium channel protein （ENaC） and aquaporin 1 （AQP₁） in acute lung injury brought on by acute ischemic kidney injury in rats.Methods A total of 60 healthy male Wistar rats （300-320 g） were randomly（random number） divided into control groups（group A， n=30）and acute kidney injury group（group B， n=30）. The model of acute ischemic kidney injury in rats was made by bilateral renal arteiovenous blockage with clamps. Six rats of each group were sacrificed at 0， 2， 4， 6 and 8 hours after modeling. Lung tissue of rats was harvested and stained with hematoxylin-eosin （HE） staining method， and the pathological changes of lung were observed under microscope. The ratio of wet and dry weight （W/D） of lung was calculated. The levels of protein in bronchoalveolar lavage fluid （BALF） were measured. The levels of IL-6 and TNF-α both in serum and BALF were tested. The concentrations of AQP₁ and α-ENaC in lung were measured. Results At six hours after modeling， the pH value of arterial blood of rats in group B began to get lowered compared to group A. There was no difference in partial pressure of oxygen in arterial blood between two groups during entire period of experiment（P＞0.05）. Protein level in BALF and W/D of lung increased significantly two hours after modeling in rats of group B（P<0.05）.The histopathological changes of acute lung injury including swollen aleolar epithelium， widened interalveolar septum， edema of alveoli and alveolar interstitium， alveolar neurophil sequestration， erythrocytes and protein in exudates were observed. The levels of TNF-α and IL-6 in serum and in BALF began to increase at two hours after modeling. The levels of AQP₁ and α-ENaC of lung in rats with acute kidney injury decreased gradually and were lower than those in rats of group A （P< 0.05）. Conclusions Aleolar epithelial-endothelial barrier function was already compromised at the beginning of AKI， suggesting the acute lung injury was already brought on. The levels of TNF-α， IL-6 in serum and in BALF increased after the occurrence of acute kidney injury. The decreases in lung AQP₁ and α-ENaC might contribute to the lung injury caused by early acute kidney injury. 【Key words】Acute kidney injury； Acute lung injury； Cytokine； Aquaporin 1； Epithelial sodium channel protein
急性肾损伤（acute kidney injury，AKI）是十分常见、复杂的临床问题之一。危重患者中有30%的患者发生急性肾损伤。虽然透析技术及高级治疗方法不断改进，但急性肾损伤的病死率仍居高不下，达到了40%～60%。在本质上，肾功能衰竭本身通常并不是AKI的死因，而是心源性和非心源性急性肺损伤（ALI）导致了AKI的高病死率^［1］。但急性肾损伤如何引起急性肺损伤的机制仍不十分清楚。因此，笔者拟通过双肾动静脉夹闭建立急性缺血性肾损伤大鼠模型，观察急性肾损伤后大鼠肺的病理生理变化，研究大鼠急性肾损伤后，IL-6 、TNF-α、水通道蛋白1（AQP₁） 及钠通道蛋白的变化规律，来探究急性肾损伤后急性肺损伤（ALI）的发病机制。以便为急性肾损伤伴发或继发急性肺损伤的预防、早期诊治提供实验及理论依据。
1 材料与方法
1.1 实验动物与试剂
健康雄性Wistar大鼠60只，体质量300～320 g，由中国医科大学动物中心提供。所用仪器与试剂包括便携式心电监护仪（HEWLETT PACKARD M3046A，德国）、5%水合氯醛、大鼠AQP₁ ELISA试剂盒（Uscnlife 公司）、大鼠IL-6 与TNF-α ELISA试剂盒（上海森雄科技实业公司）、α-ENaC抗体（SANTA公司）。
1.2 实验方法
1.2.1 动物模型制备和分组 健康雄性Wistar大鼠，予5%水合氯醛300 mg/kg腹腔麻醉，气管切开，颈动静脉穿刺，留置导管。监测呼吸频率、心率、收缩压、舒张压、平均动脉压及中心静脉压。大鼠的状态稳定0.5 h后，随机（随机数字法）分成2组，每组30只。健康对照组（A组），腹正中切口，分离双侧肾动静脉，不予结扎双肾动静脉；急性肾损伤组（B组），腹正中切口，分离双侧肾动静脉，双肾动静脉夹闭。
1.2.2 标本收集与检测 造模后，各组大鼠分别于实验开始后的0、2、4、6、8 h处死，每个时间点处死6只大鼠。所有大鼠处死前采集动脉血用于血气分析，处死后留取静脉血标本用全自动生化分析仪测定血肌酐。开胸暴露两肺，先观察肺脏大体改变，结扎右肺门，取右上肺，用4%多聚甲醛固定；常规石蜡包埋、切片、苏木素-伊红（HE）染色，光镜下检查肺组织病理变化；取右下肺，用滤纸吸去右肺下叶血，称湿质量后，置烘箱中（80 ℃，72 h）烘至恒重，称干质量，计算肺湿干比（W/D）(责任编辑：论文发表网)转贴于八度论文发表网: http://www.8dulw.com(论文网__代写代发论文_论文发表_毕业论文_免费论文范文网_论文格式_广东论文网_广州论文网)