[Effects of intranasal interferon gamma on transforming growth factor-β1/Smad in rats with allergic rhinitis].

Objective: To investigate the effects of intranasal interferon gamma (IFN-γ) on nasal mucosa remodeling and expression of transforming growth factor-β1 (TGF-β1), Smad2, Smad3, Smad7 in allergic rhinitis (AR) rat model.

Methods: Ovalbumin (OVA) and aluminum hydroxide were used to construct the AR model. Thirty AR rats were randomly divided into positive control group (group B, n = 10), IFN-γ treatment group (group C, n = 10) and negative control group (normal rats, n = 10). After the AR models were built, 50 µl PBS, 1 µg IFN-γ was dropped into the nasal cavity of each rat in group B and group C, from the fouth week to tenth week, twice a week. The nasal mucosa was collected on day 71 in order to observe the pathologic changes, and the expression of TGF-β1, TGF-β1 mRNA, Smad2 mRNA, Smad3 mRNA and Smad7 mRNA by immunohistochemistry and reverse transcriptase-polymerase chain reaction.

Results: Decreases of TGF-β1, Smad2 and Smad3 mRNA were seen in nasal tissue of group C (0.59 ± 0.04, 0.39 ± 0.08, 0.46 ± 0.15) as compared with group B (0.82 ± 0.12, 0.70 ± 0.18, 0.95 ± 0.26), the differences were significant (q value were 3.15, 4.47, 3.03, all P < 0.05). The levels of Smad7 mRNA expression increased significantly (q = 2.98, P < 0.05) in group C (0.31 ± 0.05) as compared with group B (0.25 ± 0.06). Immunohistochemistry showed significant decrease of TGF-β1 expression in the nasal tissue of group C much lesser than that in group B.

Conclusions: Intranasal IFN-γ could decrease the expression of TGF-β1, TGF-β1 mRNA, Smad2 mRNA, Smad3 mRNA, increase the expression of Smad7 mRNA in AR rats model and inhibit the nasal mucosa remodeling.