Expression of interferon-gamma, interleukin-4 and interleukin-5 mRNA in the nasal mucosal membrane of rats with allergic rhinitis.

The production of immunoglobulin E (IgE) antibody is largely dependent on the ratio between interleukin-4 (IL-4) (a T helper 2 (Th2)-type cytokine) and interferon-gamma (IFN-gamma) (a T helper 1 (Th1)-type cytokine). Interleukin-5 (IL-5) (also a Th2-type cytokine) is an important eosinophil differentiation factor and also co-stimulates B-cell growth and differentiation. The present study was designed to evaluate and compare the expression of IFN-gamma, IL-4 and IL-5 mRNA in the nasal mucosal membrane of sensitized Brown-Norway (BN) rats. Fourteen BN rats were divided into two groups: non-sensitized (control) and sensitized. The sensitized group was injected with ovalbumin (OA) intraperitoneally on three consecutive days. Twenty-one days later, rats were exposed to 1% OA aerosol. Twenty-four hours after exposure to aerosol, nasal mucosa was extracted from both groups and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed. The densities of the bands of IL-4, IL-5 and IFN-gamma mRNA were expressed as percentages against beta-actin mRNA. Our results showed that the mean values for IL-4 and IL-5 mRNA were increased significantly in sensitized rats compared with control rats. In contrast, the mean value for IFN-gamma mRNA was significantly lower in sensitized rats compared with those of the control group. Our data therefore suggest that sensitization of rat nasal mucous membranes results in the predominant expression of Th2-type cytokines.