Clinical And Experimental Study On Therapeutic Mechanisms Of Xiaoqinglong Decoction For Allergic Rhinitis Through Thymic Stromal Lymphopoietin

ObjectiveThe study aims to explore the possible therapeutic mechanisms,targets to immune regulation molecular mechanisms of Xiaoqinglong Decoction(XQLD)in the treatment of allergic rhinitis(AR),through a mouse model of ovalbumin(OVA)-induced AR and clinic observation research,for its clinical curative effect and further development to provide experimental basis.Methods1.Clinical research:30 patients with moderate to severe persistent AR which was traditionally diagnosised as lung deficiency syndromes in ENT(ear,nose,and throat)clinic were enrolled in the study.All patients willingly received XQLD treatment.The case-control study is used in the trial.Each patient was treated by XQLD for a 2-week period.Visual analog scale(VAS)scores for nasal symptoms were assessed before and after XQLD therapy.At each clinic visit,the Rhinoconjunctivitis Quality of Life Questionnaire(RQLQ)was recorded.The level of TSLP(thymic stromal lymphopoietin,TSLP),IL-4,and IFN-?in nasal lavage were evaluated by using ELISA.2.Experimental research:sixty SPF female BALB/c mice(45~59 days old),weighing 18~24g,were randomly divided into six groups(ten mice per group),namely,AR model,XQLD high-dose,XQLD medium-dose,XQLD low-dose,PAT(prednisone acetate tablets),and control groups.AR mice models were established through OVA sensitization.BALB/c mice were sensitized by intraperitoneal injection of 25?g OVA emulsified in 2 mg aluminium hydroxide in 300?l phosphate buffered saline(PBS)once every 7 days for two weeks.Mice were then challenged intranasally with 10?l of OVA solution(100?g dissolved in PBS)into each nasal cavity once daily from day 21 to day 28.For nonsensitized control mice,PBS plus aluminium hydroxide without OVA was injected,and they were challenged intranasally with PBS.XQLD treatment groups were orally administered with XQLD of 120g/kg(XQLD high-dose group),60g/kg(XQLD medium-dose group),and 30g/kg(XQLD low-dose group)30min before challenge.AR and control groups were treated with10ml/kg of PBS.PAT group was treated with 5mg/kg of PAT.The frequencies of sneezing and nasal scratching were counted,and the nasal secretions were recorded in mice for 15 minutes immediately after each intranasal challenge;The nasal mucosa was stained by hematoxylin eosin(HE)for the pathological test;The expression of TSLP in nasal mucosa were investigated by immunohistochemistry technology;TSLP in nasal mucosa and lavage were detected through ELISA;IL-4,IL-5,IL-13,and sIgE in mouse serum were determined by ELISA.Results1.Clinical research:after 2-week treatment of 30 patients with moderate to severe persistent AR,TNSS(total nasal symptom score),INSS(individual nasal symptom score),and systemic symptoms(chills,sweat,cough,sputum thin)were significantly decreased compared with baseline scores(P<0.05).TNSS was significantly decreased after 2-week XQLD treatment from 27.367±1.351 to 8.466±1.127(P<0.05)compared with the baseline scores;Among INSS,itching score wase decreased from 6.867±1.008to 2.033±1.189(P<0.05);nasal congestion score decreased from 5.833±1.085to 3.033±0.850(P<0.05);sneezing score decreased from 6.300±0.877 to2.400±0.814(P<0.05);runny nose score decreased from 8.367±0.999 to1.000±0.871(P<0.05);The total score of RQLQ from from 27.367±1.351 to23.700±1.466(P<0.05).The content of TSLP in nasal lavage was decreased from 35.286±6.472pg/ml to 20.956±4.308pg/ml(P<0.05).The ratio of IL-4/IFN-?was also decreased from 2.608±0.412 to 1.760±0.602(P<0.05).No obvious adverse reactions were observed in all patients treated with XQLD for allergic rhinitis.2.Experimental research:as a result,a murine model of allergic rhinitis was successfully developed:a total symptom score of each sensitized mouse was 5 or more.Histomorphological changes show that XQLD can reduce the inflammatory cells infiltrated into the nasal mucous membrane.Immunohistochemistry detected the expression of TSLP in the nasal mucosa.The expression of TSLP in AR group is higher than control group.Whereas the expression of TSLP was inhibited by XQLD and PAT.Compared with the control group,the levels of IL-4,IL-5,IL-13,sIgE,and TSLP in model group were higher significantly(P<0.05).The contents of IL-4,IL-5,IL-13,sIgE,and TSLP were significantly decreased in XQLD high dose group,middle dose group and PAT groups compared with the model group(P<0.05).In contrast,the levels of IL-4,IL-5,IL-13,sIgE,and TSLP in XQLD low dose group were also decreased,but no differences statistically(P>0.05).Conclusions1.XQLD can attenuate allergic inflammation possibly through down-regulated production of TSLP and inhibiting Th2 type immune responses.2.XQLD treatment for patients with moderate to severe persistent AR which was traditionally diagnosised as lung deficiency syndromes has significant clinical efficacy and safety.3.XQLD has effects on reducing the levels of TSLP and Th2-type Cytokines in AR,especially significantly decreasing in XQLD high dose group and middle dose group.XQLD may play an antiallergic role by inhibiting the expressions of TSLP produced by epithelial cells,and then suppressing dendritic cells(DCs)activated by TSLP to prime naive CD4~+T cells to differentiate into T helper type 2(Th2)cells that produced high amounts of IL-4,IL-5,IL-13,and further resulted in increasing sIgE.4.The significant clinical efficacy of XQLD treatment for a mouse model of OVA-induced allergic rhinitis was achieved in XQLD high and middle dose groups,but not in XQLD low dose group.