Effect of dietary vitamin E supplementation on murine nasal allergy

Background: Although many studies have reported the effects of dietary vita min E on the immune response, none so far has assessed its role in nasal al lergy. Methods: Female BALB/c mice were randomized into two groups and fed a 20% casein diet (control group, 50 mg vitamin E/kg diet) or this diet sup plemented with 535 mg vitamin E/kg diet (vitamin E group, 585 mg vitamin E/ kg diet) for 4 weeks. During the fifth week, the mice in each group were di vided into two subgroups to form a total of four treatment groups: group A (control), group B [control + toluene diisocyanate (TDI) sensitization], gr oup C (vitamin E supplementation), and group D (vitamin E supplementation TDI sensitization). Groups B and D were treated with two courses of intran asal application of 5% TDI in ethyl acetate, whereas groups A and C were tr eated with ethyl acetate alone. A week after second sensitization all group s were provoked by applying 2.5% of TDI in the vehicle and nasal allergic r esponses were observed for 10 minutes. Splenic lymphoproliferation, splenic cell cytokines, and the total serum IgE were measured. Results. Members of group D had lower (P < 0.01) scores of nasal response and sneezed less fre quently (P < 0.01) than those of group B. Similarly, splenic lymphoprolifer ation and production of IL-4 and IL-5 as well as the total serum IgE levels were lower (P < 0.01) in group D than in group B. Conclusions: The results indicate that higher doses of vitamin E supplementation may suppress nasal allergic responses.