本文選題：5-羥色胺　切入點(diǎn)：迷走神經(jīng)　出處：《浙江大學(xué)》2013年碩士論文

【摘要】：研究背景： 胃食管反流病(Gastro Esophageal Reflux Disease, GERD)的呼吸系統(tǒng)表現(xiàn)非常廣泛,如慢性咳嗽、難治性哮喘、反復(fù)肺炎,嚴(yán)重影響患者生活質(zhì)量。胃食管反流性咳嗽(GER induced cough, GERC)是指與GER相關(guān)的以咳嗽為主要表現(xiàn)的呼吸道癥候群,常規(guī)抑酸治療效果并不理想,因此尋找有效的GERC治療藥物非常必要,它的發(fā)病機(jī)制引起廣泛關(guān)注。其中,食管-支氣管反射引起的氣道神經(jīng)源性炎癥是其主要的病理生理機(jī)制。 反射機(jī)制的提出是以食管和氣管共同起源于胚胎前腸且具有共同的迷走神經(jīng)通路為基礎(chǔ)的,已有研究表明食管迷走C纖維是主要神經(jīng)通路。反流時(shí),酸刺激食管內(nèi)的酸敏感受體促發(fā)迷走神經(jīng)活動(dòng),通過食管-支氣管反射,使氣道感覺神經(jīng)受到刺激。瞬時(shí)感受器電位香草酸受體1(transient receptor potential vanilloid receptor1,TRPV1)在迷走神經(jīng)C纖維上表達(dá),對辣椒素敏感,也稱辣椒素敏感受體(VR1),對酸、溫度或炎癥介質(zhì)非常敏感。TRPV1激活后,可開放離子通道,C纖維興奮后末梢釋放神經(jīng)肽,神經(jīng)肽主要有神經(jīng)肽A(NKA)、神經(jīng)肽B(NKB)、P物質(zhì)(SP),它們直接刺激咳嗽感受器或通過引起炎癥、影響氣道敏感性間接引發(fā)呼吸道癥狀。5-羥色胺(5-hydroxytryptamine,5-HT)又稱血清素(serotonin),是腸神經(jīng)系統(tǒng)內(nèi)的重要神經(jīng)遞質(zhì),調(diào)節(jié)胃腸道感覺、運(yùn)動(dòng)、分泌,其在GERD發(fā)病機(jī)制中的作用也受到廣泛關(guān)注。研究表明5-HT具有選擇性的刺激食管迷走神經(jīng)傳入纖維的特性,這為研究GERC的發(fā)病機(jī)制提供了新的方向。因此,我們根據(jù)已有研究提出如下假設(shè)：食管內(nèi)的酸反流時(shí),如食管黏膜5-HT分泌增加,可激活迷走神經(jīng)C纖維,通過食管-支氣管神經(jīng)反射通道,引起速激肽的釋放,導(dǎo)致氣道神經(jīng)源性炎癥,氣道反應(yīng)性增高,而引起咳嗽等呼吸道癥狀。 目的： 確定5-HT-迷走神經(jīng)C傳入纖維通路在食管酸反流致氣道高反應(yīng)性中的作用及其機(jī)制,分析影響5-HT-迷走神經(jīng)C傳入纖維-神經(jīng)肽分泌途徑的藥物對食管酸反流致氣道高反應(yīng)性的防治作用,為食管反流所致氣道高反應(yīng)性的治療提供新的靶點(diǎn)。 方法： 普通級(jí)健康雄性白化豚鼠30只(7周齡,體重300g-400g),隨機(jī)分成：模型組、對照組和空白組。模型組豚鼠經(jīng)胃管在食管的中下段以18ml/h的速率緩慢灌注0.1mmol/1的HCL溶液(含0.5%胃蛋白酶),持續(xù)20min,每天一次,連續(xù)14d,以建立GER模型。對照組用蒸餾水代替鹽酸灌注；空白組不做任何處理。檢測不同濃度乙酰甲膽堿(Mch)對豚鼠肺阻力和肺順應(yīng)性的變化,評估氣道反應(yīng)性；采集支氣管肺泡灌洗液(BALF)進(jìn)行白細(xì)胞計(jì)數(shù)和分類計(jì)數(shù),并利用酶聯(lián)免疫吸附法測其中NKA、NKB、SP含量；評估食管、氣管和肺組織病理變化；采用高效液相色譜-電化學(xué)法測食管組織5-HT和5-HIAA含量；分別利用RT-PCR和Western Blot測定食管TRPV1、5HT4R、SERT的mRNA和蛋白表達(dá)的水平。進(jìn)一步在每次食管酸灌注之前30min分組(每組10只)采用5HT4R拮抗劑GR113808(1μmol/kg)和TRPV1拮抗劑辣椒平(capsazepine,0.5μmol/kg)進(jìn)行腹腔注射2周,觀察其干預(yù)效果。 結(jié)果： 1.GER動(dòng)物模型的建立和氣道高反應(yīng)性。當(dāng)Mch剌激濃度達(dá)到0.25mMol/L和0.5mMol/L時(shí),模型組肺阻力增加百分比和肺順應(yīng)性減少百分比大于對照組和空白組,氣道反應(yīng)性增高；差異具有統(tǒng)計(jì)學(xué)意義。模型組遠(yuǎn)端食管黏膜出現(xiàn)潰瘍糜爛,炎癥表現(xiàn)明顯；氣管組織和肺組織炎癥明顯,主要以嗜酸性粒細(xì)胞浸潤為主,而對照組和空白組遠(yuǎn)端食管黏膜結(jié)構(gòu)完好,支氣管和肺泡結(jié)構(gòu)正常。模型組BALF中的白細(xì)胞總數(shù)和嗜酸性粒細(xì)胞百分比,及NKA和SP含量均顯著高于對照組和空白組。模型組食管組織中5-HT水平顯著高于對照組和空白組,而SERT mRNA表達(dá)水平明顯降低。TRPV1mRNA,5-HT4RmRNA和蛋白表達(dá)水平在三組間的差異沒有統(tǒng)計(jì)學(xué)意義；模型組TRPV1蛋白表達(dá)水平高于對照組和空白組,但差異無統(tǒng)計(jì)學(xué)意義。 2.藥物干預(yù)結(jié)果：Mch濃度為0.5mMol/L時(shí),GR113808組和辣椒平組的肺阻力增加百分比和肺順應(yīng)性減少百分比小于模型組,氣道高反應(yīng)性得到一定程度緩解。兩藥物干預(yù)組食管黏膜、氣管黏膜和肺組織的炎癥程度比模型組有所減輕。而GR113808組的BALF中白細(xì)胞總數(shù)和嗜酸性粒細(xì)胞計(jì)數(shù)均比模型組有所下降,辣椒平組的白細(xì)胞總數(shù)低于模型組。兩組BALF中SP含量均比模型組有所降低。 結(jié)論： 豚鼠食管酸灌注模型可以引起食管黏膜損傷、氣道神經(jīng)源性炎癥和氣道高反應(yīng)性；食管酸灌注可引起食管組織5-HT升高和SERT的降低,5-HT-迷走神經(jīng)通路可能在食管酸反流致氣道高反應(yīng)性中發(fā)揮作用；5-HT4R拮抗劑GR113808和TRPV1拮抗劑辣椒平可有效降低食管酸反流引起的氣道反應(yīng)性,并減輕肺部組織炎癥,5HT4R和TRPV1有望成為治療GERC的新靶點(diǎn)。
[Abstract]:Research background:
Gastroesophageal reflux disease (Gastro Esophageal Reflux Disease, GERD) of the respiratory system is very extensive, such as chronic cough, refractory asthma, recurrent pneumonia, seriously affect the life quality of patients. Gastroesophageal reflux cough (GER induced, cough, GERC and GER) is related to cough as the main manifestation of respiratory tract the syndrome of conventional acid suppression therapy effect is not ideal, so the search for effective drug therapy for GERC is necessary, its pathogenesis has aroused widespread concern. Among them, the airway neurogenic inflammation caused by esophageal tracheobronchial reflex is the main pathophysiological mechanism.
The reflection mechanism is to the trachea and esophagus originate from embryonic foregut and vagus pathway based on common, studies have shown that esophageal vagal C fiber is the main pathway. Reflux, acid sensitive receptor in esophageal acid stimulation by stimulating vagus nerve activity, esophageal tracheobronchial reflex, the airway sensory nerve the stimulation. The transient potential vanilloid receptor 1 (transient receptor potential vanilloid receptor1, TRPV1) C expression in vagal fibers, sensitive to capsaicin, also called capsaicin sensitive receptor (VR1), the acid, temperature or inflammatory mediators is very sensitive to the activation of.TRPV1, can open the ion channel, neuropeptide C fiber endings release after excitation mainly, neuropeptide neuropeptide A (NKA), neuropeptide B (NKB), substance P (SP), which direct stimulation of cough receptors or by causing inflammation, airway sensitivity indirect effect Respiratory symptoms of.5- hydroxytryptamine (5-hydroxytryptamine, 5-HT) also called serotonin (serotonin), is an important neurotransmitter in enteric nervous system, regulating gastrointestinal sensation, movement, secretion, its role in the pathogenesis of GERD has received extensive attention. Studies show that 5-HT has a selective stimulation of esophageal vagal afferent fibers, the provide a new direction for the study of the pathogenesis of GERC. Therefore, we propose a hypothesis based on the previous research: esophageal acid reflux, esophageal mucosa such as increased secretion of 5-HT, can activate vagal nerve fibers by C, esophageal tracheobronchial reflex channels caused by tachykinin release, leading to airway neurogenic inflammation, airway hyperresponsiveness, caused by respiratory symptoms such as cough.
Objective:
To determine the 5-HT- C pathway in the vagal afferent fibers of esophageal acid reflux caused by the effect and mechanism of airway hyperresponsiveness in the prevention of drug effect analysis on the effect of 5-HT- C vagal afferent fibers - neuropeptide secretion pathway on esophageal acid reflux induced airway hyperresponsiveness, provide a new target for the treatment of esophageal reflux caused by airway hyperresponsiveness the.
Method錛，

本文編號(hào)：1730540