外源性CGRP对ALI大鼠肺组织AQP1及p-JNK表达的影响

Effect of CGRP on the expressions of AQP1 and p-JNK in lung tissue of ALI rats

目的探讨外源性降钙素基因相关肽(CGRP)对脂多糖诱导的急性肺损伤(ALI)大鼠肺组织水通道蛋白(AQP)1和磷酸化c-Jun氨基端蛋白激酶(p-JNK)表达的影响及可能的致病机制。方法将42只SD大鼠随机分为NS对照组(NS组)、CGRP对照(CGRP)组、6 h ALI组、12 h ALI组、6 h干预组(6 h Control组)和12 h干预组(12 h Control组)各7只。ALI组按10 mg/kg尾静脉注射LPS后6 h和12 h后分别取材;干预组按5μg/kg尾静脉注射药物CGRP 1 h后再予LPS(10 mg/kg)尾静脉注射,后分别于6 h和12 h后分别取材;CGRP对照组予CGRP(5μg/kg)尾静脉注后6 h取材;NS组按NS(1 ml/kg)尾静脉注射后6 h取材。比较各组大鼠肺泡灌洗液(BALF)中细胞计数及分类计数、湿/干重比值(W/D);分别用免疫组织化学(IHC)和Western印迹检测各组大鼠肺组织AQP1和p-JNK蛋白表达水平。结果ALI组大鼠BALF细胞总数和分类计数、W/D比值和p-JNK的表达量较NS组明显增高,AQP1表达较NS组明显下降(均P<0.05);相同时段ALI组BALF中细胞分类计数和p-JNK的表达量较干预组明显增加,肺组织AQP1表达量较干预组明显下降(均P<0.05)。CGRP组与NS组大鼠BALF中细胞计数及细胞分类计数百分比、p-JNK表达和AQP1表达差异不明显(P>0.05)。结论外源性CGRP可上调ALI大鼠肺组织AQP1的表达水平,抑制p-JNK的活化,可减轻LPS诱导的ALI大鼠炎症反应和肺水肿的程度。

Objective To investigate the effect of calcitonin gene-related peptide(CGRP)on expressions of aquaporin(AQP)1 and phosphorylated c-Jun amino terminal protein kinase(p-JNK)in lung tissue of acute lung injury(ALI)rats induced by lipopolysaccharide(LPS).Methods 42 SD rats were divided into NS control group(NS group,n=7),CGRP control group(CGRP group,n=7),ALI group(ALI group,n=14)and CGRP intervention group(CGRP intervention group,n=14)by random number method.ALI group was divided into 6 h and 12 h subgroups(n=7),the CGRP intervention group was divided into 6 h and 12 h subgroups(n=7).The ALI group was injected with LPS at 10 mg/kg at 6 hours and 12 hours after the tail vein injection;the CGRP intervention group was injected with 5μg/kg CGRP at the tail vein for 1 hour and then LPS(10 mg/kg)was injected at 6 hours and 12 hours.The samples of ALI and CGRP intervention groups were taken at tail vein injection 12 hours later.CGRP control group received 5μg/kg CGRP tail vein injection for 6 hours;NS group received normal saline 0.2 ml(1 ml/kg)tail vein injection for 6 hours.The samples of CGRP control and NS groups were taken at tail vein injection 6 hours later.BALF cell count and classification count and wet/dry weight ratio(W/D)of SD rats in each group were recorded and compared;immunohistochemistry(IHC)and Western blot were used to detect expressions of AQP1 and p-JNK protein.Results The total number and classification of BALF cells,the W/D ratio and the expression of p-JNK of ALI group were higher than those of NS group(P<0.05),and expression of AQP1 was lower than that of NS group(P<0.05).The differences were all statistically significant.In the same period,the cell classification count in BALF and p-JNK expression in ALI group were significantly increased(P<0.05),and the expression of AQP1 was significantly decreased compared with CGRP intervention group(P<0.05).There were no significant differences in total cell count and cell classification count in BALF cells,p-JNK expression and AQP1 expression between NS and CGRP control groups(P>0.05).Conclusions Exogenous CGRP could up-regulate the expression of AQP1 in lung tissues of ALI rats,inhibit the activation of p-JNK,and reduce the degree of inflammation and pulmonary edema in ALI rats induced by LPS.