| Bronchial Asthma is a widespread chroncic disease to children and the pathogenesis is very complicated and pooly understand now. According to global initrative for asthma of 2002 ( GINA) , asthma was considered a chronic disease of airway , and there was much cell and cell component involving in this important process , companied with enhanced responsiveness, neural regulation of airway likely participated in respiratory inflammation and regulation of airway caliber, it maybe associated with the asthma repeated outbreak for airway inflammatory and airway regulation abnormably. With the further study of asthma ,it pays attention to neural -mechanism of asthma more and more. Recently,it is important for the neurogenic inflammation in airway which mediated by sensory neu-ropeptides secreted by sensory nerve in the asthma pathogenesis. With the further understanding to the neural - mechanism of asthma , investigators found that neuropeptidesA(NKA) , neuropeptides B(NKB) ,substantsP(SP) do not react directly, but also react through their own cell receptor . Now there are three subtypes of sensory neuropeptides receptor, including NK1 , NK2 and NK3 receptor. NKA is effect on NK2 receptor and then they are relationship with the formation of airway hyperreactivity of asthma. NK2 receptor is considered one of most important receptors of neural - mechanism of asthma. Baitr elt considered that NK2 and NK1 receptor of asthma patients is rising apparently, so the reason that airway hyperreactivity and chronic inflammation persistently exist is the content of tachykini and own receptors inhancing and action enhancig each other. Recently , asthma therapy in clinical introduce is inhalation hormone by GINA. It is not clear whether hormone can decline neuropeptide receptors. It contributes to consummate asthma pathogenesis for studing neuropeptide receptors deeply, pro-viding new basis of current theapy , looking for new theapy.Our study will study NK2 receptor content and contrubution on asthmatic guinea - pig airway and lung and whether hormon can decline the NK2 receptor . There is no correlative report on NK2 receptor involving in asthma pathogenesis in our home , rarely in overseas.Material and methods1 Animal model :The routin ways is that the guinea pigs were sensitized by exposure to aerosolized ovalbumin (1% wt/vol in 0.9% sterile sodium chloride ) on 2 occasions separated by 7 days (the day at 1,4,7),3 min on each occasion ; the sensitizing in routin ways were exposured to aerosolized 2% ovalbumin for 5 min after a further week (the day at 21) to provoke asthma attack. Inhaling hormone seven days before provking(the day at 14). The control were exposure to aerosolized NS instead of ovalbumin and hormone.2 Animal sample collection: studied guinea pigs and control must sample collection at the same time (24 hours after provking) guinea pigs were anesthetized with pentobarbital. Take the trachea and lung tissue in a non ?Rnase tube and stored them in liquid nitrogon . The other tissue of trachea and lung were fixed by 4% citromint,for making paraffinsection.3 MethodsHybridization in situ : Using the oligonucleotide probe to NK2 receptor , cardiox marking to detect the mRNA of NK2 receptor in the trachea and lung tissue (in situ).Reverse transcription - polymerase chain reaction ( RT - PCR ) : Total RNAs were extacted using TRIZOL reagent from the lung tissue . cDNA was amplified by using primers after synthesized from mRNA. The density of bands were assessed and amount of mRNA for NK2 receptor was determined as a ratio to ($ - actin.StatisticsData were expressed as x + s. Statistical analysis was performed with t test .Results1. NK2 receptor mRNA exprssion can be observed in the trachea , bronchus and the lung tissue to asthmatic guinea pigs. NK2 receptor mRNA are mainly located in the submucosa and around the smooth muscle of the trachea and bronchus and less located around the blood vessels besides above .2. The relative content of NK2 receptor mRNA of asthmatic guinea p...
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