摘要
目的探讨红景天苷(salidroside,SAL)是否通过介导Toll样受体4/核转录因子-κB/NOD样受体蛋白3(TLR4/NF-κB/NLRP3)信号通路改善重症肺炎(severe pneumonia,SP)大鼠肺组织损伤。方法Wistar大鼠75只,随机选择15只作为假手术组,其余60只通过气管内滴注肺炎克雷伯菌(Klebsiella pneumoniae,Kp)悬液诱导构建SP大鼠模型。建模成功大鼠随机分为模型组、SAL低剂量组(30 mg/kg)、SAL高剂量组(60 mg/kg)和地塞米松(dexamethasone,DXMS)组(15 mg/kg),每组15只,假手术组和模型组均灌服等量生理盐水,连续7 d。检测肺组织湿干重比(Wet/Dry,W/D);HE和TUNEL染色观察各组大鼠肺脏组织形态及细胞凋亡情况;ELISA法检测支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF)中TNF-α、IL-1β、IL-6、IL-18及IL-10水平;Western blot检测肺组织中TLR4、髓样分化因子(myeloid differentiation factor 88,MyD88)、NF-κBp65、磷酸化NF-κBp65(phosphorylated NF-κBp65,p-NF-κBp65)、NLRP3蛋白相对表达水平。结果经气管滴注Kp悬液成功构建SP大鼠模型;与假手术组比较,模型组大鼠肺组织水肿严重,W/D值升高(P<0.05),肺泡结构松散不完整,肺泡壁水肿增厚,大量炎性细胞浸润,细胞凋亡率升高,BALF中炎性因子TNF-α、IL-1β、IL-6及IL-18水平升高,IL-10水平降低,肺组织中TLR4、MyD88、NF-κBp65、p-NF-κBp65及NLRP3蛋白相对表达水平升高(P<0.05);与模型组比较,SAL低、高剂量组及DXMS组大鼠肺组织病理损伤情况均逐渐改善,W/D值降低(P<0.05),肺泡结构逐渐完整,肺泡壁水肿程度逐渐减轻,细胞凋亡率降低,BALF中炎性因子TNF-α、IL-1β、IL-6及IL-18水平降低,IL-10水平升高,肺组织中TLR4、MyD88、NF-κBp65、p-NF-κBp65及NLRP3蛋白相对表达水平降低(P<0.05);低、高剂量SAL及DXMS改善SP大鼠肺组织损伤的作用效果表现为逐渐增强(P<0.05)。结论SAL可减少细胞凋亡,改善由Kp诱导的大鼠肺组织病理损伤,其作用机制可能与阻断TLR4/NF-κB/NLRP3信号通路激活,抑制炎性因子表达有关。
Objective To investigate whether salidroside(SAL)improves lung tissue injury in rats with severe pneumonia(SP)through mediating toll-like receptor 4/nuclear transcription factor-κB/NOD-like receptor protein 3(TLR4/NF-κB/NLRP3)signaling pathway.Methods Seventy-five Wistar rats were used in this study.Fifteen of them were randomly selected as the sham operation group,and the others were induced by endotracheal infusion of Klebsiella pneumoniae(Kp)suspension to construct a rat model of SP.After modeling,the rats were randomly divided into four groups with 15 rats in each group:model group,low-dose SAL group(30 mg/kg),high-dose SAL group(60 mg/kg)and dexamethasone(DXMS,15 mg/kg)group.The sham operation group and the model group were given the same amount of normal saline for seven consecutive days.The wet-dry weight ratio(W/D)of lung tissues in each group was detected.HE and TUNEL staining methods were used to observe the morphology of lung tissues and cell apoptosis.The levels of TNF-α,IL-1β,IL-6,IL-18 and IL-10 in bronchoalveolar lavage fluid(BALF)were detected by ELISA.The expression of TLR4,myeloid differentiation factor(MyD88),NF-κBp65,phosphorylated NF-κBp65(p-NF-κBp65)and NLRP3 at protein level in lung tissues was detected by Western blot.Results The rat model of SP was successfully constructed by endotracheal infusion of Kp suspension.Compared with the sham operation group,the model group showed more severe edema of lung tissues,increased W/D value(P<0.05),loose and incomplete alveolar structure,edema of alveolar wall and thickened alveolar wall,massive inflammatory cell infiltration,increased apoptosis rate as well as higher levels of TNF-α,IL-1β,IL-6 and IL-18 and lower lover of IL-10 in BALF.Moreover,the relative expression of TLR4,MyD88,NF-κBp65,p-NF-κBp65 and NLRP3 at protein level in lung tissues was increased in the model group(P<0.05).Gradually improved pathological injury of lung tissues,decreased W/D value(P<0.05),recovered alveolar structure,reduced alveolar wall edema and decreased cell apoptosis rate were observed in the low-dose and high-dose SAL groups as well as the DXMS group as compared with those of the model group.Besides,the three groups also showed decreased levels of TNF-α,IL-1β,IL-6 and IL-18 and increased level of IL-10 in BALF,and inhibited expression of TLR4,MyD88,NF-κBp65,p-NF-κBp65 and NLRP3 at protein level in lung tissues(P<0.05).DXMS performed better in improving lung injury in rats with SP,followed by high and low doses of SAL(P<0.05).Conclusions SAL could reduce cell apoptosis and improve the Kp-induced lung injury in rats.The mechanism might be related to the blockage of TLR4/NF-κB/NLRP3 signaling pathway activation and inhibition of inflammatory factor expression.
作者
叶培军
夏傲
葛昀
何谦益
Ye Peijun;Xia Ao;Ge Yun;He Qianyi(Department of Critical Care Medicine,Affiliated Cancer Hospital of Zhengzhou University,Zhengzhou 450008,China;Department of Neurology,the First Affiliated Hospital of Zhengzhou University,Zhengzhou 450000,China)
出处
《中华微生物学和免疫学杂志》
CAS
CSCD
北大核心
2023年第2期130-136,共7页
Chinese Journal of Microbiology and Immunology
基金
河南省医学科技攻关计划(LHGJ20210301)。
作者简介
通信作者:叶培军,Email:yes1208@163.com。
