Period2 gene regulates diurnal changes of nasal symptoms in an allergic rhinitis mouse model.

Background: Allergic rhinitis (AR) symptoms exhibit prominent 24-hour variations associated with the biological clock. Although endogenous glucocorticoids synchronize circadian oscillator in the nasal mucosa, the precise mechanism of AR remains unclear. Therefore, using a mouse model, we investigated the association between circadian-clock genes and AR symptoms at various time-points.