OBJECTIVETo study the effects of cool restrain stress on the accumulation of eosinophils and expression of Th cytokines in rat nasal mucosa with allergic rhinitis model.

METHODSFifty healthy female rats were randomly divided into 5 groups: control group, allergic rhinitis (AR) group, AR plus stress group, stress plus AR group and simultaneous stress-AR group. Cool restrain stress, AR model and simultaneous stress-AR were made. Nasal mucosa of septum from rats of five groups were stained routinely by haematoxylin eosin (HE) and immunohistochemistry respectively. The density of eosinophils and expression of interleukin (IL)2, IL-6 were observed by using software of image analysis systems under microscope.

RESULTSThe density of eosinophiles and IL-6 in the nasal mucosa of stress-AR group were significantly higher than those in AR [(14.1 +/- 3.2) for eosinophiles, and (15.3 +/- 4.8) for IL-6 ] and were also significantly higher than those in control groups [(2.3 +/- 1.4) for eosinophiles, and (4.9 +/- 2.4) for IL-6)], and the differences reached statistical significance. (F were respectively 7.06, 7.14, 8.54, 8.20, P were respectively < 0.05 or < 0.01), but no significant differences of the three groups (AR plus stress, stress plus AR and simultaneous stress-AR groups) were found (F were respectively 2.90 and 3.20, P > 0.05). The expression of IL-2 in nasal mucosa of stress-AR group was significantly reduced compared with AR and control groups (F were respectively 7.27, 7.32, P were respectively < 0.05 or < 0.01). But there were also no significant differences of the three groups (AR plus stress, stress plus AR and simultaneous stress-AR groups, F = 3.12, P > 0.05).

CONCLUSIONSThe abnormal infiltration and accumulation of eosinophiles and the differences in expression of IL-2 and IL-6 which represented Th1 and Th2 cytokines in rats nasal mucosa varied in different groups. The eosinophiles and IL-6 were rarely expressed in control group and moderately expressed in AR group, but significantly expressed in cool restrain groups. The IL-2 representing Th1 cytokines were reduced in cool restrain stress gruops. All these results indicated that cool restrain stress might play a role in inducing rat allergic rhinitis.