TRPV1/NF-κB信号通路在右美托咪定减轻大鼠VILI中的作用

Role of TRPV1/NF-κB signaling pathway in dexmedetomidine-induced alleviation of VILI in rats

目的评价瞬时受体电位香草酸1(TRPV1)/核因子-κB(NF-κB)信号通路在右美托咪定减轻大鼠呼吸机相关性肺损伤(VILI)中的作用。方法清洁级健康雄性SD大鼠100只,体重270~320 g,4~5月龄,采用随机数字表法分为5组(n=20):对照组(C组)、VILI组(V组)、AMG9810组(A组)、右美托咪定组(D组)和右美托咪定+RTX组(DR组)。采用潮气量40 ml/kg机械通气4 h的方法制备VILI模型。A组机械通气前1 h腹腔注射TRPV1抑制剂AMG981030 mg/kg;D组与DR组机械通气前经20 min静脉输注右美托咪定5.0μg/kg,机械通气期间以5.0μg·kg^(-1)·h^(-1)的速率静脉输注;DR组机械通气前连续3 d每天腹腔注射TRPV1激动剂RTX 70μg/kg。机械通气4 h时,检测支气管肺泡灌洗液(BALF)IL-1β、TNF-α和IL-6浓度,测定氧合指数(OI)和肺湿重/干重(W/D)比值,观察肺组织病理学结果,行肺损伤评分。Western blot法检测肺组织TRPV1和NF-κB的表达,RT-PCR法检测TRPV1 mRNA和NF-κB mRNA的表达。结果与C组比较,V组BALF IL-1β、TNF-α和IL-6浓度升高,OI降低,W/D比值和肺损伤评分升高,TRPV1、NF-κB及其mRNA表达上调(P<0.05);与V组比较,A组、D组、DR组BALF IL-1β、TNF-α和IL-6浓度降低,OI升高,W/D比值和肺损伤评分降低,TRPV1、NF-κB及其mRNA表达下调(P<0.05);与D组比较,DR组BALF IL-1β、TNF-α和IL-6浓度升高,OI降低,W/D比值和肺损伤评分升高,TRPV1、NF-κB及其mRNA表达上调(P<0.05)。结论右美托咪定减轻大鼠VILI的部分机制与抑制TRPV1/NF-κB信号通路激活,抑制肺组织炎症反应有关。

Objective To evaluate the role of transient receptor potential vanilloid receptor 1(TRPV1)/nuclear factor-κB(NF-κB)signaling pathway in dexmedetomidine-induced alleviation of ventilator-induced lung injury(VILI)in rats.Methods One hundred clean-grade healthy male Sprague-Dawley rats,weighing 270-320 g,aged 4-5 months,were divided into 5 groups(n=20 each)using a random number table method:control group(group C),VILI group(group V),AMG9810 group(group A),dexmedetomidine group(group D),and dexmedetomidine+RTX group(group DR).VILI model was prepared by mechanical ventilation with a tidal volume of 40 ml/kg for 4 h.In group A,TRPV1 inhibitor AMG981030 mg/kg was intraperitoneally injected at 1 h before mechanical ventilation.Dexmedetomidine 5.0μg/kg was intravenously infused at 20 min before mechanical ventilation,and dexmedetomidine was intravenously infused at the rate of 5.0μg·kg^(-1)·h^(-1) during ventilation in group D and group DR.In group DR,RTX 70μg/kg was intraperitoneally injected for 3 consecutive days before mechanical ventilation.At 4 h of mechanical ventilation,the concentrations of interleukin-1beta(IL-1β),tumor necrosis factor-alpha(TNF-α)and IL-6 in bronchoalveolar lavage fluid(BALF)were detected,oxygenation index(OI)and wet/dry lung weight(W/D)ratio were measured,the histopathological changes of lung tissues were observed,and lung injury was assessed and scored.The expression of TRPV1 and NF-κB in lung tissues was detected by Western blot,and real-time polymerase chain reaction was used to detect the expression of TRPV1 and NF-κB mRNA.Results Compared with group C,the concentrations of IL-1β,TNF-αand IL-6 in BALF were significantly increased,OI was decreased,the W/D ratio and lung injury scores were increased,and the expression of TRPV1 and NF-κB protein and mRNA was up-regulated in group V(P<0.05).Compared with group V,the concentrations of IL-1β,TNF-αand IL-6 in BALF were significantly decreased,OI was increased,the W/D ratio and lung injury scores were decreased,and the expression of TRPV1 and NF-κB protein and mRNA was down-regulated in A,D and DR groups(P<0.05).Compared with group D,the concentrations of IL-1β,TNF-αand IL-6 in BALF were significantly increased,OI was decreased,the W/D ratio and lung injury scores were increased,and the expression of TRPV1 and NF-κB protein and mRNA was up-regulated in group DR(P<0.05).Conclusions The mechanism by which dexmedetomidine alleviates VILI is partially related to inhibition of the activation of TRPV1/NF-κB signaling pathway and inhibition of the inflammatory responses in lung tissues of rats.