The Study Of Behavioral Traits And Their Molecular Mechanisms In Mice Model Of Allergic Rhinitis

Allergy is greatly threatening the health of mankind, in which an abnormal adaptive immune responses directed against normally harmless environmental substance, e.g. pollen, dust etc. Recently, especially after the industrial revolution, the prevalence of allergy has increased quickly. And allergic rhinitis (AR) has been received increasing attention because it is the most common allergy. Besides, it was reported that allergy including AR was associated with anxious, depressive mood disorders, and in adolescence AR increased the risk of depression in their later life. But, it is not clear that whether AR initiate, perpetuate or exacerbate the pathological mood disorders; whether AR in adolescents caused a permanent effect on the brain. It is important to uncover the mechanisms of relationship between AR and mood disorders.Thus, we built juvenile mice model of allergic rhinitis using OVA as allergen, tested their behaviors in different situation of allergen exposure and the molecular mechanism for the abnormal behavioral traits.1) Behavioral tests showed that C57BL/6 juvenile AR mice presented higher anxiety-like and depression-like behaviors during OVA allergen exposure.2) Behavioral tests showed that C57BL/6 juvenile AR mice with and without PA treatment showed no significant behavioral changes after long term OVA allergen isolation. During OVA allergen re-exposure, AR mice without PA treatment presented no significant behavioral changes, but AR mice with PA treatment showed higher anxiety-like behavior.3) Behavioral tests showed that BALB/c juvenile AR mice showed lower stereotypic behavior, higher depression-like behavior and lower social memory after a short term allergen isolation. Immunostaining of c-fos showed that 12 hours after the last nasal challenge, neural cells in periventricular nucleus (PVN) and lateral septum dorsal part (LSd) were inhibited, while no significant changes in prefrontal cortex (PFC) and medial amygdala (MeA); After behavioral tests, no significant changes of neural cells activity in LSd, PFC and MeA, but the microglia cells were activated in the forebrain cingulate cortex area. RT-PCR tests for mRNA levels showed that no significant changes of BDNF, LTR-9, and CRF depression-related gene expressions can be found in the cortex and striatum of AR mice after behavioral tests.In conclusion, inhibition of neurons in LSd and PVN brain areas and activation of microglial cells in cingulate cortex may contribute to depression-like behaviors and social memory deficits after short-term allergen isolation in BALB/c AR mice. During allergen exposure, C57BL/6 juvenile AR mice showed higher anxiety-like behaviors and depression-like behaviors. After long-term allergen isolation, C57BL/6 juvenile AR mice behaved normally, but AR mice with PA treatment showed higher anxiety-like behaviors during allergen re-exposure.