Stability of the synaptic structure in the hippocampus of BALB/c mice with allergic rhinitis

Objective: The aim of this study was to determine whether allergic rhinitis can induce structural changes in the synapse formation in the hippocampus of BALB/c mice immunocytochemically. Methods: Allergic rhinitis was induced in mice by two intra-peritoneal injections of ovalbumin administered with a one-week interval. After two weeks, the sensitised mice were challenged with an intra-nasal injection of ovalbumin for two weeks. To analyse the hippocampal synaptic structures, sections were immunostained with antibodies against glutamic acid decarboxylase 65 and glutamic acid decarboxylase 67 (for γ-aminobutyric acid-ergic terminals), synaptophysin (for glutamatergic and γ-aminobutyric acid-ergic terminals) and spinophilin (for dendritic spines). The number of nasal rubbing movements was significantly greater in the allergic rhinitis mice than in the control mice. However, the expression patterns of the four above-mentioned synaptic markers in the hippocampus showed no detectable difference between the allergic rhinitis and control mice. Results and Conclusion: These data indicate that the synaptic structure in the hippocampus might remain unaltered in allergic rhinitis patients.