Study On The Mechanism Of Action Of Carboxypeptidase A3 In Mouse Model Of Allergic Rhinitis

Objective: The aim was to investigate the role of mast cell carboxypeptidase A3(CPA3)in a mouse model of allergic rhinitis(AR)and to explore its specific mechanism.Methods: Six-week-old female SPF-grade BALB/C mice were selected,and 200 μL of a mixture of ovalbumin(OVA)with aluminum hydroxide and magnesium hydroxide was injected intraperitoneally on days 0,7,and 14,and transnasal excitation with 10 μg/μL OVA,15 μL/nasal,was performed for 7 consecutive days starting on day 21 to establish an allergic rhinitis mouse model.The mice were observed to scratch their noses and sneeze for 15 min after the last OVA excitation,and the specimens were collected after 24 h.The infiltration of nasal mucosa was detected by conventional pathology,including cupped cells,mast cells and eosinophils;the nasal mucosa was detected by immunohistochemistry,Quantitative Real-time PCR or Western-blot for CPA3,occludin,claudin-1 and JAM-A expression changes.OVA-sIgE concentration in serum was quantitatively assessed using enzyme-linked immunosorbent assay.Finally,changes in the Th1/Th2 cell ratio in the spleen of mice were assessed by flow cytometry.Results: Compared with the control group,the nasal mucosa of OVA-induced allergic rhinitis mice showed a large infiltration of eosinophils and mast cells,and significant proliferation and hypertrophy of cupped cells,while CPA inhibitor treatment significantly reduced eosinophil infiltration and cupped cell proliferation,but did not affect the infiltration of mast cells;the severe nose scratching and sneezing symptoms in the AR group were also improved by the inhibition of CPA3.The severe nose scratching and sneezing symptoms in the AR group were also improved by the inhibition of CPA3,which was accompanied by a decrease in serum OVA-sIgE concentration in AR mice;CPA inhibitor attenuated the decreased expression of claudin-1,JAM-A and ocrelipin in the nasal mucosa of AR mice and reversed the Th1/Th2 cell imbalance.Conclusion: CPA3 can promote eosinophil infiltration and cupped cell proliferation in the nasal mucosa of AR mice,and aggravate the symptoms of scratching and sneezing in AR mice;CPA3 can aggravate the destruction/weak repair of JAMA,claudin-1 and ocludin in the nasal mucosa of AR mice,which in turn leads to/maintains the development of AR;CPA3 can aggravate the Th1/Th2 cell imbalance in AR mice and participate in the course of AR,and CPA3 is promising as a new therapeutic target for AR.