| Research Background:CVA(Cough variant asthma)is a special type of asthma.CVA is the only or main clinical manifestation of this disease.It is not accompanied by obvious wheezing,shortness of breath,wheezing between the laryngeal and other symptoms,but it has airway hyperresponsiveness.The etiology and pathogenesis of CVA are still not clear,but most scholars believe that CVA is a chronic inflammation of airway allergen,which is the early stage of typical asthma.Transient receptor potential vanillic acid subtype 1(TRPV1)is a nonselective cationic channel that is widely distributed in sensory nerve fibers of mammals.Currently,studies have confirmed that the expression of this gene is increased in the respiratory tract of patients with asthma,chronic cough and gastrointestinal reflux.The supervisor,Professor Yang Daowen,under the guidance of Professor Chao Enxiang,applied the prescription of invigorating qi and reducing stomach on the basis of treating CVA from the perspective of wind,and achieved a good clinical effect.Based on the legislation of invigorating qi and dispelling wind,lung and stomach simultaneously,the prescription of invigorating qi and dispelling wind provided a new treatment idea for this disease.Objective:In this study,the effect of Yiqi Shufeng Jiewei Decoction on the pathological changes of lung tissue in CVA model rats was observed,the expression of TRPV1 in the lung tissue of rats was detected and statistically analyzed,and the target of Yiqi Shufeng Jiewei Decoction in the treatment of CVA was discussed.Research methods:60 healthy male rats were randomly divided into five groups:blank control group,CVA model group,Yiqishufengjiangwei decoction group,budesonide western medicine group,capsicapin TRPV1 antagonistic group,with 12 rats in each group.Except blank group,rats in other groups were sensitized by injection of 1ml mixed solution of OVA and Al(OH)3 on day 1 and day 8,of which 0.5ml was injected into the hind plantar of the two feet and both sides of the neck,back and waist and groin,0.5ml was injected into the abdominal cavity(each 1ml mixed solution contained 2mg OVA and 3 100mg AL(OH)).Blank control group was injected with the same amount of normal saline at corresponding points.From day 15,rats in the model group,Chinese medicine group,western medicine group and capsaicin group were placed in a closed glass atomization box,and atomized with 1%OVA solution for 20 minutes,while rats in the blank group were atomized with sterile water for injection for 20 minutes,once a day,10 times in total.Each treatment group was given corresponding drug treatment 30 minutes before each atomization.Mental state,behavioral response,hair gloss,defecation and water intake were observed and recorded in each group.Body weight of rats was measured regularly.After reaching the administration cycle,rats in each group were placed in a closed cough induction box with length*width*height of 70 cm*45 cm*50 cm for 8 minutes.After that,alveolar lavage fluid and lung tissue samples were obtained.The cell count and cell classification in BALF of rats were observed by cell smear,and the pathological morphology of lung tissue was observed by HE staining.Finally,RT-qPCR was used to detect the expression of TRPV1 in lung tissues of rats in each group.Research results:(1)General conditions:in blank group,mental state was good,hair color was smooth and bright,movement was sensitive,breathing was stable,eating and drinking water amount was good,defecation was normal,and weight gain was stable.During OVA atomization stimulation,other groups showed abdominal twitching,accelerated breathing,erection of hair,frequent washing of face and scratching,etc.,and the model group showed progressive aggravation.Before the experiment,the mental state of rats in each group was good,and some rats were slightly dark,irritable,slow and slow in reaction,but there was no significant difference in water intake and weight gain compared with the blank group(P>0.05).(2)COUGH:Compared with blank group,the cough frequency of rats in CVA model group was significantly increased,with statistical significance(P<0.05);Compared with model group,cough frequency of TCM group,western medicine group and capsaicin group decreased to different degrees,with statistical significance(P<0.05).(3)Pathological changes:in the blank group,the bronchial structure at all levels was normal,the tracheal lumen was unobstructed,the bronchial epithelial cells were intact,the smooth muscle shape was normal,the tube wall structure was clear,there was no inflammatory cell infiltration in the lung interstitium,the alveolar septum was normal,the alveolar lumen was clean,and no mucus plug was formed.In the model group,airway smooth muscle thickened,bronchial wall congestion and edema were observed,mucosal epithelial cells were injured,ciliary prostrate and loss were observed,a large number of inflammatory cells mainly composed of eosinophils,lymphocytes and neutrophils were observed in the lung interstitium,the surrounding alveolar septum was widened,alveolar collapse was observed,and mucus plugs were observed in the tracheal lumen.Compared with the model group,the pathological structure of the traditional Chinese medicine group,the western medicine group and the capsaicin group were improved in different degrees.(4)BALF cell count:compared with the normal group,the total number of white blood cells,the absolute count of EOS and the proportion of EOS in BALF of the model group were increased to different degrees(P<0.05);Compared with CVA model group,the total number of cells,EOS count and EOS proportion in each treatment group were decreased to varying degrees(P<0.05),and the differences were statistically significant.(5)TRPV1 expression:The expression of TRPV1 gene in model group was significantly higher than that in blank control group(P<0.05).The expression of TRPV1 gene in capsaicin group was significantly lower than that in model group(P<0.05).The expression of TRPV1 in the Chinese medicine group was lower than that in the model group,and the difference was not statistically significant(P>0.05),but there was a certain downward trend.Analysis conclusion:(1)The prescription of tonifying qi and dispelling wind and lowering stomach can reduce airway inflammation and airway hyperreactivity,and has a certain therapeutic effect on CVA.(2)The expression of TRPV1 was increased in the lung of CVA rats,and capsaicin,the antagonist,could down-regulate the expression of TRPV1 in the lung tissue of CVA rats,and had a therapeutic effect at the same time.(3)The prescription of invigorating qi and dispelling wind and lowering stomach may play a therapeutic role by down-regulating the expression of TRPV1 in the lung tissue of CVA rats. |
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