Abstract: Objective To evaluate the effects of different doses of exogenous Interleukin-17A(IL-17A)on airway inflammatory responses in mice with allergic rhinitis. Methods Forty-eight BALB/c female mice were assigned randomly to six groups(A, B, C, D, E, and F), with eight mice per group. Groups D, E, and F received intraperitoneal OVA injection and nasal challenge, normal saline(NS), and different doses of IL-17A(100 ng and 500 ng)one hour before nasal challenge, respectively. Groups A, B, and C received intraperitoneal NS injection and nasal challenge, NS, and different doses of IL-17A(100 ng and 500 ng)one hour before nasal challenge, respectively. Nasal symptoms were assessed at 4 weeks. Serum, nasal lavage fluid(NLF), and nasal tissue were collected. Eosinophils in NLF were measured using Diff-Quik staining. IL-6 and IL-10 levels in serum and NLF were measured using enzyme-linked immunosorbent assay(ELISA). Mast cells in nasal mucosa were measured using toluidine blue staining. Results All mice in group D had a symptom score of greater than five points, demonstrating that the model was successful. Groups A, B, C, D, E, and F had average scores of 1.5(1.0-2.8), 2.0(1.0-3.0), 2.5(2.0-3.0), 7.0(6.3-8.0), 3.0(2.3-3.8), and 8.0(7.0-8.8), respectively. Rubbing times and number of sneezes were lower in group E than in group D(H=21.375, P=0.033, H=20.250, P=0.049). Levels of IL-6 in the serum and NLF were higher in group D than in group A(H=25.750, P=0.004; H=20.688, P=0.047). IL-10 levels in the serum and NLF were lower in group D than in group A(H=22.875, P=0.016; H=20.625, P=0.048). There were no significant differences in IL-6 levels in the serum and NLF between group E and group A(H=19.875, P=0.068; H=8.125, P>0.999). IL-10 levels in the serum were higher in group E than in group D(H=27.062, P=0.002). IL-6 levels in the serum and NLF were higher in group F than in group A(H=22.250, P=0.008, H=28.688, P=0.001). There were no significant differences in IL-10 levels in the serum and NLF between group F and group D(H=13.062, P=0.930; H=0.500, P>0.999). Eosinophils in the NLF were more abundant in group C than in group A(H=20.688, P=0.047). The number of eosinophils in group E was significantly lower than that in group D(H=21.188, P=0.037). There was no significant difference in the number of eosinophils in group F compared with that in group D(H=2.875, P>0.999). Mast cells in the nasal mucosa were more abundant in group D than in group A(H=27.188, P=0.002). The number of mast cells in the nasal mucosa was lower in group E than in group D(H=20.938, P=0.042). There was no significant difference in the number of mast cells between group F and group D(H=1.188, P>0.999). Conclusion 500 ng of exogenous IL-17A led to a modest proinflammatory effect in normal mice. Treatment with 100 ng exogenous IL-17A in mice with allergic rhinitis can protect against allergic airway inflammation.

Key words: Rhinitis, allergic, IL-17A, Airway inflammation, Mouse