[Experimental studies for botulinum toxin type A on allergic rhinitis in the rat]

To study the effect of botulinum toxin-A on inhibiting rhinorrhea, on expression of VIP at nasal mucosa, on morphometrical change with an immunohistochemical and histological methods in rats allergic rhinitis.

Ovalbumin sensitized the rat as animal model of allergic rhinitis. Animals were divided into control group (n = 8), allergic group (n = 12), allergic animal treated by BTX-A group (n = 6). VIP immunoreactivity at nasal mucosa in the rat allergic rhinitis was studied by immunohistochemical. The morphometrical changes at nasal mucosa were observed by histological staining methods.

The results showed that the symptoms of allergic rhinitis, nasal rhinorrhea and sneezing, were remarkably relieved after ovalbumin application in the rat. The nasal rhinorrhea symptom diminished after BTX-A treated. The quantity of nasal secretion were significantly reduced(P < 0.05) in allergic one treated by BTX-A group as compared with allergic group. Hematoxylin and eosin staining demonstrated that no edema, small vessels were found in the nasal mucosa and after BTX-A treatment, but edema, vasodilational and inflammational cell infiltration were observed in the allergic group. Immunohistochemical study revealed that VIP immunoreactive fibers in the nasal mucosa showed a marked decrease after BTX-A application, but the density and a large number of VIP fibers were significantly found in the allergic group.

The results suggested that local BTX-A treatment was 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.