Expression Of Toll-Like Receptor 4 And NF-κBp50 In Experimental Allergic Rhinitis In Rats

Objective: 1.To establish the model of allergic rhinitis(AR)in SD rats. 2.To present the character of morphology in allergic rhinitis of rat. 3.To observe the expression of toll-like receptor 4 and NF-κBp50 in experimental allergic rhinitis ( AR) and study the effect of lipopolysaccharide (LPS) and dexamethasone on their expression by immunohistochemical staining. 4. To determine the expression of TLR4 protein in nasal mucosa by Western blotting. 5.To explore the relation of toll-like receptor 4 and NF-κBp50 in allergic rhinitis rat.Methods: 48 SD rats whose weight 250~300g were divided randomly into four groups : AR group ( group A) ;Allergic rhinitis + LPS administration group (groupB) ;Normal control group;Allergic rhinitis + dexamethasone group (groupD). The nasal mucosae were studied by Wright's staining to observe the infiltration of inflammatory cells. The numbers of eosinophile granulocytes in the epitheliumwere counted under the high power light microscope.The expression of TLR4 and NF-κBp50 proteins was detected by western-blotting and immunohistochemical staining respectively in rat nasal mucosa of all the groups. All data are represented as means±SEM. Statistical analysis was performed using one-way ANOVA and Repeated measures with SPSS13.0 statistical package. A probability value of less than 0.05 was considered significant.Results: The animal models of allergic rhinitis were made sucessfully in group A,B,D. Large number of neutrophil and eosinophile granulocyte present in nasal smear of group A,B. In nasal mucosa, EOS got increase obviously in group A,B, and then, decreased after DEX treatment. by hemotoxylineosin (HE) staining, and submucosa without inflammatory cell infiltrated and few vessels is compact fibrous connective tissue adjacent to the surface of cartilage. While, group A and group B shown a significant increase of mucosa thickness, vessels and glands, epithelium secretive cells, inflammatory cells, compared to group C and group D. After the treatment of DEX, mucosa recovered, and all of vessels expanding, glands hyperplasted and inflammatory cell infiltrated did lighten.The numbers of eosinophils: group B was significantly higher than in group A,C,D(p<0.01),and significantly higher in group A than in groupC,D(p<0.01),group C and D showed no significant difference(P>0.05).ICH staining : NF-κBp50 expressed in all the groups,the expression of NF-κBp50 in group B was significantly higher than in group A,C,D(p<0.01),and significantly higher in group A than in groupC,D(p<0.01),group C was significantly higher than group D. Western-blotting: TLR4 expressed in all the groups,the expression of TLR4 in group B was significantly higher than in group A,C,D(p<0.01),and significantly higher in group A than in groupC,D(p<0.01),group C and D showed no significant difference (p>0.05) .Conclusion: The expression of TLR4 and NF-κBp50 increased in rat nasal mucosa with experimental allergic rhinitis. The expression of TLR4 and NF-κBp50 in allergic rhinitis rats can be futher increased by LPS and decreased by the intervention of dexamethasone. It suggests that TLR4 and NF-κBp50 have an effect on allergic inflammation. Dexamethasone may decrease the expression of TLR4 and NF-κBp50,which may correlate with the development of allergic rhinitis.