Chronic stress aggravates inflammation of nasal mucosa in allergic rhinitis-induced mice model

Abstract

To investigate the effect of chronic stress on inflammation of nasal mucosa using an unpredictable chronic mild stress (UCMS) model to mimic chronic stress-like disorders. We divided BALB/c mice into four groups: control (n = 5), UCMS-exposed (n = 5), AR-induced (n = 5) and UCMS-exposed/AR-induced groups (n = 5). We measured cortisol as a marker of chronic stress and cytokines such as IFN-γ and IL-4, IL-5 representing Th1 and Th2 response, respectively, and we also examined the nasal mucous membrane histologically. UCMS exposure was confirmed by an increase in the levels of cortisol. Although there was no significant difference in Th1 cytokine (IFN-γ) levels within the groups, Th2 cytokine (IL-5) levels were significantly increased in stressed groups (UCMS-exposed and UCMS-exposed/AR-induced groups) compared to non-stressed groups (control and AR-induced groups). The histological examination of the nasal mucous membrane after antigen challenge in stressed group revealed severe dilation of blood vessels and injured olfactory hairs on the olfactory mucous membrane and severe swelling in the respiratory epithelium, compared to non-stressed group. These results suggest that chronic stress can aggravate inflammation of nasal mucosa in AR-induced mice model by shifting to the Th2 response by up-regulation of Th2 cytokines expression.