Effects of intrinsic nitric oxide on the expression of interleukin-4 and IFN-gamma mRNA in the bronchial and lung tissues of sensitized rats.

To investigate the effects of intrinsic nitric oxide (NO) on the expression of interleukin-4 (IL-4) mRNA and interferon-gamma (IFN-gamma) mRNA in the airway inflammation of asthma, the rat models of asthmatic inflammation were established by sensitizing and then challenging the animals with ovalbumin. The 24 animals were randomly divided into control group, sensitized group, sensitized and L-Arg-treated group as well as L-NAME-treated group equally. By using in situ hybridization combined with compute physiological quantitative imaging analysis techniques, the influence of intrinsic NO on the expression of IL-4 mRNA and IFN-gamma mRNA in the airway inflammatory cells was observed. In situ hybridization study demonstrated that IL-4 mRNA expression was obviously increased as compared with that in the control group, mainly distributed in the inflammatory cells in the submucous of airways in the sensitized group. The increase of intensity of IL-4 mRNA expression was positively correlated with the numbers of eosinophil (Eos) and lymphocyte (both with P < 0.05) in the sensitized group. There was no statistically difference in IFN-gamma expression between the control group and the sensitized group. Imaging analysis showed that L-NAME could inhibit the expression of IL-4 mRNA (P < 0.05) and increase the expression of IFN-gamma mRNA (P < 0.05), while L-Arg could increase the expression of IL-4 mRNA in inflammatory cells (P < 0.05). It was indicated that a suitable levels of intrinsic NO can influence the expression of IL-4 mRNA of Th2 lymphocytes and the expression of IFN-gamma mRNA of Th1 lymphocytes and in turn, promote the development of asthmatic airway inflammation.