Dietary nucleoside-nucleotide mixture aggravates nasal allergic responses induced by toluene diisocyanate in mice

Abstract

In this study we evaluated the effect of a dietary nucleoside-nucleotide mixture (NNM) on nasal allergy induced by toluene diisocyanate(TDI) in mice. Female ddY mice were randomized into two groups and fed a nucleic-acid free 20% casein (control) or this diet supplemented with NNM for 4 weeks. On the 4th week, mice were divided into 2 sub-groups; NNM sensitized, NNM- nonsensitized, control-sensitized and control-nonsensitized. The sensitized groups of mice were treated with two courses of intranasal application of 5% TDI in diethyl acetate for 5 consecutive days each time, separated by one week rest. Nonsensitized group of mice were similarly treated with vehicle. A week after the second sensitization all the treatment groups were provoked by applying 2.5% of TDI in vehicle. Nasal responses of sneezing, rhinorrhea, itching and snort at provocation, were scored for ten minutes. Degree of hair loss from the snout of mice was also scored for the length of the experiment. Lung and serum IgE were measured by ELISA. Results show that the sensitized groups of mice from each dietary group sneezed more frequently than the nonsensitized groups (p< 0.05). The NNM sensitized group sneezed more frequently that was different (p< 0.05) compared to the rest of the groups. Nasal responses for the sensitized groups were higher relative to the nonsensitized groups, with the NNM sensitized group having an overall higher nasal response than the rest of the groups. Both sensitized group of mice showed a higher concentration of lung and serum IgE compared to the non-sensitized groups (p<0.05, with the NNM sensitized group having an overall higher IgE concentrations in both tissues compared to the rest of the groups (p< 0.05). We conclude that dietary NNM may aggravate nasal allergic responses in the predisposed.