Objective: The aim of this study was to use a guinea pig model of prolonged allergic-induced rhinitis to characterize the feature of nasal mucosa remodeling.
Method: Forty-eight male Hartley guinea pigs were randomly divided into six groups: allergen challenged groups (Group OVA(2w) , Group OVA(6w) and Group OVA(12w)) and control groups respectively (Group Sal(2w), Group Sal(6w) and Group Sal(12w)). Each group had 8 guinea pigs. To develop a guinea pig model of nasal mucosa remodeling, ovalbumin-sensitized guinea pigs were repeatedly challenged with allergen twice a week from two weeks to 12 weeks. Matched control groups were challenged with physiological saline. Nasal lavage was performed 24 hours after the last intranasal challenge. Then nasal mucosa were obtained. HE, AB-PAS, MT, and immunohistochemical staining against transforming growth factor-beta1 (TGF-beta1) were performed. Eosinophil cationic protein (ECP) and OVA-special IgE (OVA-sIgE) were detected by ELISA in nasal lavage fluid.
Result: (1) The levels of OVA-sIgE in nasal lavage fluid in Group OVA(6w) and Group OVA(12w) were significantly different from Group OVA(2w), while the levels of ECP had no significant difference among the experiment groups. The levels of OVA-sIgE and ECP in experiment groups were significantly different from control groups respectively (P < 0.01). (2) Grade 0 and Grade 1 of epithelial damage were significantly different in Group OVA(6w) and Group OVA(12w) when compared with from Group OVA(2w) (P < 0.01). At the same time, Grade 0 and Grade 1 of epithelial damage were statistically different in the experiment groups when compared with the respectively control groups (P < 0.05). (3) Goblet gland hyperplasia and collagen deposit within the extracellular matrix (ECM) were easily found in Group OVA(6w) and Group OVA(12w) compared with Group OVA(2w) (P < 0.01). The number of goblet gland and the ratio of collagen deposit were statistically more in Group OVA(6w) and Group OVA(12w) than in Group Sal(6w) and Group Sal(12w) (P < 0.05). That feature of the ratio of collagen deposit did not show in Group OVA(2w) versus Group Sal(2w). (4) Increased TGF-beta1 expressions were observed in Group OVA(6w) and Group OVA(12w) compared with Group OVA(2w) (P < 0.01). Those increasing expressions were also observed in experiment groups rather than in the respectively control groups (P < 0.01).
Conclusion: Epithelial damage, goblet cells hyperplasia and collagen deposition in ECM were observed as the features of remodeling in this guinea pig model of allergic rhinitis under prolonged allergen challenge. Epithelial damage, excessive expression of related cytokines and enhancement activity of enzymes were observed in early time after challenge of allergen. The features of goblet cells hyperplasia and collagen deposition in ECM were observed at a later stage.