| Background and ObjectivesThe minimal persistent inflammation (MPI) of allergic rhinitis, a new recognition, is proposed in recent years, which is refers to the sensitive individual, when continuous exposure to under threshold dose allergens, even without any symptoms, there is still inflammatory infiltration in its nasal mucosa. MPI prompt that the therapeutic strategy of allergic rhinitis will have a new variation, which is maintenance treatment and prevention treatment. At present, there is only a few studies on prevention of AR. this study was designed to detect the changes of interleukin-12 (IL-12) in nasal mucosa by immunohistochemical method and to investigate the influence of budesonide on animal model of MPI of allergic rhinitis in rats, in order to provid the theoretical basis in animal experiment and molecular level for optimizing the prevention and treatment of allergic rhinitis.Materials and MethodsEighty Sprague-Dawley (SD) rats were randomly divided into four groups: group A (allergic rhinitis group), B (experimental group), C (MPI model group) and D(bland group) respectively, with twenty animals in each group. The group A, B and C respectively was sensitized with allergy-causing liquid I (OVA 10mg, aluminum hydroxide gel 0.5ml and PBS liquid 0.5ml) in first day and was injected with allergy-causing liquidⅡ(OVA 1 mg, aluminum hydroxide gel 0.5ml and PBS liquid 0.5ml) in eighth day. From 22nd day to 28th day, A,B and C groups were inspired in nasal cavity of rats with 1%OVA, one time per day,25μl/nose/time; Later, changed to three times per week, continue to inspire 1 week, since the 36th day, A group was still inspired with 1%OVA, B and C groups to 0.01%OVA, lasting 5 weeks, D group always was given physiological saline instead of OVA. Then, half rats were executed and observed EOS infiltration and the expression of IL-12, ICAM-1 in nasal mucosa. since 57th day, B group was given budesonide for intranasal treatment in 30 min before each stimulation, for two weeks. The dose is 64μg every time, once a day. Stop to give budesonide for two days every week after lasted five days. The rest groups were given physiological saline. Last week, the group A, B and C respectively was stimulated with 1%OVA, once a day. D group always was given physiological saline instead of OVA. Kill all rats and observed EOS infiltration and the expression of IL-12, ICAM-1 in nasal mucosa.By one-factor analysis of variance and least significant diffierence test, all experimental data were analyzed using spss 16.0 software.Results1 Rat sneezing countThe first 5 weeks, The count of sneeze had no obvious difference among the three groups of A, B and C (P>0.05). Three groups showed that typical symptoms of sneezing.6-8 weeks, the sneezing number of rats in group B and C were decreased markedly than that in group A, and compared with A group, the difference was obviousC P＜0.05). The 1 1th week, the sneezing number of rats in group A and C were more markedly than that in group B, and had obvious difference compared with that in D group, The rats of group D had sneeze occasionally and had no any other symptoms.2 Eosinophilic infiltrateW8:The eosinophilic count of group A was much more than the other three groups. B and C groups had a little infiltration and had obvious difference compared with A group (P＜0.05)Wll:The group B had a little infiltration and had significant difference compared with the group A and C (P<0.05), D group had no difference compared with B group (P>0.05).3 The expression of ICAM-1In nasal mucosa of rats, the ICAM-1 present mainly in the cytoplasm of epithelial cells, eosinophils, basophils eosinophilic, and showed brown.W8:There were a great quantity positive cells in nasal mucosa of group A. The positive cells of Group B and C had a mild expression.Group D had no positive cells. The group A had significant difference compared with the group B and C (P<0.05) D group had no difference compared with B and C group (P>0.05).Wll:There were many positive cells in A and C groups and without positive cells in B and C groups. The group B had significant difference compared with the group A and C (P<0.05) and had no obvious difference compared with groups D (P>0.05).4 The expression of IL-12IL-12 positive signals mainly present in mucosal epithelium and glandular epithelium of nasal mucosa, showed brown yellow.W8:The positive cells had sporadic expression in group A and had a small quantity expression in group B and C. The expression of positive cells was significant in group D. Group D had obvious difference compared with the other three groups (P＜0.05)Wll:The positive cells had sporadic expression in group A and C. The expression of positive cells was significant in group D and B. Group D and B had obvious difference compared with the other two groups (P＜0.05)Conclusions1. Budesonide significantly inhibited the late reaction of animal model of minimal persistent inflammation(MPI) of allergic rhinitis in rats.2. Budesonide significantly inhibited the EOS infiltration of animal model of minimal persistent inflammation(MPI) of allergic rhinitis in rats.3. Budesonide significantly increased the expression of IL-12 and inhibited the expression of ICAM-1 in MPI model. |
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