Effect of transient receptor potential vanilloid-1 on cough hypersensitivity induced by particulate matter 2.5

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• 作者：Haining Lv^a ; Jianliang Yue^a ; Zhe Chen^b ; Senlin Chai^a ; Xu Cao^a ; Jie Zhan^a ; Zhenjun Ji^a ; Hui Zhang^c ; Rong Dong^d ; ^{13913920819@163.com" class="auth_mail" title="E-mail the corresponding author} ; Kefang Lai^b ; ^{klai@163.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：PM2.5 ; Cough reflex sensitivity ; TRPV1 ; SP ; Neurogenic inflammation ; Dorsal vagal complex
• 刊名：Life Sciences
• 出版年：2016
• 出版时间：15 April 2016
• 年：2016
• 卷：151
• 期：Complete
• 页码：157-166
• 全文大小：3083 K

文摘

The mechanism of cough hypersensitivity induced by particulate matter 2.5 (PM2.5) remains elusive. The current study was designed to explore the effect of transient receptor potential vanilloid-1 (TRPV1) on cough hypersensitivity in airway and central nervous system.

Main methods

The PM2.5-induced chronic cough model of guinea pig was established by exposure to different doses of PM2.5 for three weeks. After exposure, the animals were microinjected with TRPV1 agonist capsaicine, antagonist capsazepine in the dorsal vagal complex respectively. Cough sensitivity was measured by determining the provocative concentration of citric acid inducing 5 or more coughs (C5). Airway inflammation was detected by hematoxylin eosin (HE) staining and Evans blue fluorescence, and substance P (SP) and TRPV1 expressions in airway were observed by immunohistochemical staining. TRPV1 expressions in the dorsal vagal complex were observed by immunofluorescence. Retrograde tracing by pseudorabies virus-Bartha (PRV-Bartha) was conducted to confirm the regulatory pathway between airway and central nervous system.

Key findings

PM2.5 induced TRPV1 expressions in both of airway and dorsal vagal complex and airway neurogenic inflammation. Airway vascular permeability increased after being exposed to PM2.5. The expressions of SP in the airway and airway inflammation was increased after microinjecting TRPV1 agonist, and decreased after microinjecting TRPV1 antagonist. PRV infected neurons in medulla oblongata mainly located in the dorsal vagal complex.

Significance

These findings show that TRPV1 in the dorsal vagal complex could promote airway neurogenic inflammation and cough reflex sensitivity through neural pathways of vagal complex-airways, which indicate the therapeutic potential of specific inhibition of TRPV1 for chronic cough induced by PM2.5.