Gene Expression And Protein Determination Of Complements And Complement Regulatory Proteins In The Nasal Mucosa Of Allergic Rhinitis Rat

Allergic rhinitis is a worldwide disease threatening the health of people. It is one of allergic diseases of type I , which is, IgE-mediated inflammation. Recent years, complement system, especially the anaphylatoxins C₃a, C₄a and C₅a is demonstrated to be involved in the mechanism of allergic diseases of type I, including allergic bronchial asthma, urticaria and allergic rhinitis. The activation of complement is regulated by the Complement Regulatory Proteins (Regulators of Complement Activation, RCA). The exact manchanism that complement and complement receptors contribute to immunopathology of allergic rhinitis and whether complement regulatory proteins involved in the disease still remain unclear. Therefor, here we try to elucidate the inside relationship between complement system and the immunopathology of allergic rhinitis through investigating the mRNA expression and determination the protein of Complement C₃, C₄ and complement regulatory proteins C₁INH , MCP (CD46) in allergic rhinitis rat nasal mucosa . More studies following may offer new ways to therapy allergic disease by regulating complement or complement regulatory proteins.Objective: To study the relationship between the complement system and the pathogenesis of allergic rhinitis, through investigate the protein level and the level of mRNA expression of Complement C₃,C₄ and Complement Regulatory Proteins C₁-INH, MCP (CD46) in the nasal mucosa of allergic rhinitis rat.Methods: 20 healthy SD rats were randomly allotted into AR group and control group, 10 rats for each group. 10 rats was sensitized and intranasally challenged by ovalbumin and AIOH₃ (as supplement) as allergic rhinitis models, and the control group was treated by saline. The nasal mucosa in respiratory area of both groups was obtained. RT-PCR methods was adopted to investigate the level of mRNA expression of complement C3, C4 and MCP(CD46) in nasal mucosa of both groups. Then, Western-Blotting was carried to investigate the protein of C₃, C₄, C₁INH and MCP.Results: C₃ mRNA expression were detected in both groups, and the level in AR group was higher than that of the controls (p<0.05), while C₄ shows no difference between the two groups. The C3 level of the group of AR is higher than that of the control group (p<0.05) . Both of the protein level and the mRNA expression of CD46 show significant difference between the two groups (p<0.01) ,and the value of AR group is higher than that of the control group. The other one of the complement regulatory proteins, C₁-INH shows nodifference between the two groups.Conclusions: The high level of C3 and the up-regulation of its mRNA expression in nasal mucosa of allergic rhinitis rat suggests that the complement component C3 is involved in the immunopathology of allergic rhinitis. And, the high level of membrane cofactor protein (CD46) and the up-regulation of its mRNA expression suggest that the complement regulatory protein CD46 is also involved in the immunopathology of allergic rhinitis. The only difference of C3 and CD46 but C4 and CiINH may indicate that the complement system involved in the rat's allergic rhinitis is activated by other ways except the classical pathway.