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

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.

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.

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.

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.