Establishment And Evaluation A Murine Model Of Oral Allergy Syndrome

Objective: This study aims to establish a murine model of oral allergy syndrome with peanut extracts as a specific allergen and to elucidate the underlying mechanism.Methods: A total of 20 female BALB/c mice(6-8 week-old)were randomly divided into a normal control group and a model group;each group consisted of 10 mice.A sensitization mixture was made of CPE(crude peanut extract)and cholera toxin at a ratio of 10:1(W/W).Mice were under light anesthesia by inspiration of ethyl;the sensitization mixture(soaked in a cotton ball)was applied to the buccal mucosa of both sides,3 times a day for 14 consecutive days.On day 15,the mice were challenged with [CPE 10 mg per mousein 300 μL(PBS)] via gavage-feeding as well as directly contacting the buccal mucosa.Control group were given same doses of PBS in sensitization stages and PBS in place of CPE in challenge stages.Anaphylactic symptoms were evaluated from each mouse after challenge.The mice were sacrificed 4 h later.Mast cells and eosinophils in the sections were stained with toluidine blue or hematoxylin and eosin respectively,and observed by a light microscope.The serum levels of CPE-specific Immunoglobulin E(Ig E)were determined by enzymelinked immunosorbent assay(ELISA).Furthermore,the levels of mouse mast cell protease-1(m MCP-1)in the serum and the cytokines of Interleukin(IL)-4 and IFN-gamma(IFN--γ)in culture supernatant of the spleen cells were assessed by ELISA with kits following the manufacturer’s instructions.Results: 1.Systemic anaphylactic symptoms were evident within 5 to 15 minutes after challenged with CPE by means of wipe the oral mucosa and intragastric gavage.The initial reactions consisted primarily of cutaneous reactions with puffiness around the oral and lips,scratching and rubbing around the mouth and nose,diarrhea,reduced activity,or both followed by respiratory reactions,such as wheezing and labored respiration.The PBS treated and challenged mice did not show any symptoms of anaphylaxis.The CPE-treated mice symptom of anaphylaxis,the scores were higher in the group sensitized and challenged than that of PBS-treated(p < 0.001).2.Hematoxylin and eosin staining showed that in the CPE group,there was less inflammatory cell infiltration in the oral mucosa.In the CPE group,we observed that eosinophil cell infiltration,vein exangia and congestion in the oral mucosa and submucous coats by light microscope.Toluidine blue staining showed a large number of mast cells in the oral mucosa;the mast cells were in large size,irregular shape;part of the mast cells were degranulating.In the PBS group,much less mast cells were observed in the control group.Compared with PBS group,the count of mast cells,degranulated mast cells and eosinophils were increased in the CPE group(p < 0.01).3.Hematoxylin and eosin staining showed that in the CPE group,the small intestinal villi were not well-arranged,villus fell off or sparse intestinal villi and structural damage were also observed.The number of eosinophils was markedly increased in the lamina propria.The intestinal structure was integrity,stage was clear and intestinal villi were neatly arranged in the PBS group.In the CPE group,we observed large number of mast cells,some of them degranulated in the intestinal mucosa.The number of the mast cells and degranulated mast cells and eosinophils of the CPE group were more than that in PBS group(p < 0.05).4.Compared with PBS group,the CPE group showed significantly higher serum levels of CPE-specific Ig E and m MCP-1(p < 0.05).Compared with PBS group,the CPE sensitized mice showed higher levels of IL-4 in spleen cell culture supernatant(p < 0.01).The CPE group did not show the increase in the expression of IFN-gamma as compared to the control group(p > 0.05).Conclusion: The murine model of oral allergy syndrome induced by peanut allergens was successfully established.The allergic reaction of oral mucosa is mediated by Ig E and it is accompanied by the occurrence of allergic reaction to intestinal mucosa.The model simulates the pathogenic process of human oral allergy syndrome,which is consistent with the immunological characteristics of oral allergy syndrome.