Inhibition of rhinorrhea with botulinum toxin type A and the expression of VIP on nasal mucosa in allergic rhinitis rat

AIM: To study the effect of Botulinum toxin A (BTX A) on inhibition of rhinorrhea, expression and morphological change of Vasoactive intestinal polypeptide (VIP) at nasal mucosa, in allergic rhinitis (AR) rats. METHODS: Ovalbumin sensitized the rat to establish allergic rhinitis model. Rats were divided into control group ( n =6), allergic group ( n =10), allergic rats treated with BTX A (AR+BTX A) group ( n =5). VIP immunoreactivity at nasal mucosa in the allergic rhinitis rats was studied by immunohistochemistry. The morphological changes at nasal mucosa were observed by histological staining methods. RESULTS : The symptoms of allergic rhinitis, nasal rhinorrhea and sneezing, were remarkably augmented after ovalbumin application. The nasal rhinorrhea symptom diminished after BTX A treatment. The quantity of nasal secretion was significantly reduced in (AR+BTX A) group as compared with that in allergic group ( P 〉0.05). The nasal sneezing symptom in AR+BTX A group was not significantly different with that in the allergic group. Hematoxylin and eosin staining demonstrated that no edema, small vessels were found in AR+BTX A group, but edema, vasodilational and inflammation cell infiltration were observed in the allergic group. Immunohistochemical study revealed that VIP immunoreactive fibers at the nasal mucosa decreased markedly after BTX A application, but a large number of VIP fibers were observed in the allergic group. CONCLUSION: Local BTX A treatment is a selective and non traumatic method to reduce a long lasting desensitization of the nasal mucosa,to alleviate nasal congestion,rhinorrhea and sneezing, and to reduce the sensory neuron sensitivity of the mucosa.