ABSTRACT
OBJECTIVE To study the histopathologic and microvascular changes in allergic rhinitis nasal mucosa of SD rats following persistent exposure to allergen. METHODS A total of 60 heathy SD rats were divided into two groups randomly: the persistence group(n=30)and the control group(n=30). The animals of the persistence group were exposed to allergen persistently after modeling of 7 weeks with OVA provocation in nasal mucosa for 16 weeks. At 8, 12, 16 weeks after OVA provocation each group were sacrificed at each time point. The animals of control group were not provocated and were sacrificed at the same time point. Their nasal mucosa of 5 animals from each group were observed under optical microscope and the other 5 animals were used to made microvascular corrosion casts to observe microvascular changes under scanning electron microscope. RESULTS In the persistence group, the early histopathological transformation was acute inflammatory reaction, nasal mucosa tissues congestion, partial nasal mucosa shedding. The inflammation cells infiltrated into the submucosa. The acute inflammatory reaction declined as the time went by. Then the nasal mucosa repaired step by step. Damaged epithelium repaired in a certain extent with fibration, but the restoration result of epithelial are untidiness, goblet cell volume is increased and metaplasia submucosal blood vessels increased, Through scanning electron microscope, we found the capillary of nasal mucosa expanded and congested, the vascular endothelial cell swelled. As time went by, the capillary hyperplasia and the microvascular endothelial cell analosis even microvascular wall anomalism. CONCLUSION Inflammatory injury at early stage after allergen provocation, the mucosa hyperblastosis and friber restoration in mucosa tissue and microvascular networks reconstitution at later stage form a histopathological basis of dysfunction after persistent exposure to allergen.