STUDY ON INFLAMMATORY CELLS IN BALF OF SMOKE-INDUCED CHRONIC BRONCHITIS RAT MODEL

Objective To establish a smoke-induced chronic bronchitis rat model and evaluate the patho-logical change semi-quantitatively, and study the characteristics of the inflammatory cells in the bronchoalveolar lav-age fluid (BALF) in various stages. Methods Chronic bronchitis sequential rat model was established by passively inhaling smoke mixture. Experiments were performed in 30 young male Sprague-Dawley rats, which comprised 5 groups in random, i.e.,4 chronic bronchitis model groups and 1 control group. After stained with hematoxylin and eosin, the specimens were studied by semi-quantitative method to evaluate the morphologic changes in various stages. Meanwhile, the inflammatory cells of the BALF and the activity of myeloperoxidase (MPO) of lung tissue were analysed. Results During the process of the chronic bronchitis, the pathologic score was increasing as time went on, and the typical morphologic changes of chronic bronchitis emerged in the group 7 weeks. The total number of inflammatory cells in BALF was increasing as time went on, correlated with the pathologic scores (P <0.01). And the percentage of lymphocyte increased as well as positively correlated with pathologic scores (P < 0. 05) , whereas that of macrophage decreased and negatively correlated with pathologic scores (P <0. 05). The MPO lever of lung tissue was correlated with the pathologic scores (P < 0. 01). But the percentage of the neutrophil in the BALF was just in a high level during the first week, then it maintained relatively lower. Conclusion Smoke-induced chronic bronchitis is a slowly progressive inflammation process. The model we established is convenient and simple for the longitudinal study on the inflammatory process of chronic bronchitis and the therapy in the early stage. The semi-quantitative evaluation for the pathological change is with much more value. During the inflammatory sequential process of early stage of chronic bronchitis, the cellular characteristics are similar to that of the common chronic inflammation.

Effects of interleukin-18 on airway inflammation and the Th1/Th2 cytokine imbalance in guinea pig asthmatic model

In order to investigate the effects of interleukin-18 （IL-18） on airway inflammation and the Th1/Th2 cytokine balance in guinea pig asthmatic model as well as its possible mechanisms, the asthmatic model was established by intraperitoneal injection of ovalbumin （OVA） and aerosol challenges into guinea pigs, and 30 treated animals were randomly divided into three groups of 10 animals in each groups, in which group A served as the asthmatic model, group B as the controls and group C as the group treated with IL-18. The counting and categorization of the inflammatory cells in bronchoalveolar lavage fluid （BALF） were performed by using light microscopy, and the contents of cytokines （ IFN-γ, IL- 2, IL-4 and IL-5） were assayed by means of the ELISA kit. The experimental results showed that the numbers of eosinophils （ESO） in BALF of group A, B and C were （97.70 ± 58.03） × 10^6/L, （11.68 × 9.95） × 10^6/L and （28.62 ± 10.46） × 10^6/L, respectively, in which the number of eosinophils in group A was significantly higher than those of group B and C. Also, the number of neutrophils in BALF of group A was even higher than those in group B and C. In addition, the contents of IFN-7 and IL-2 in group A were lower than those in group B and C, but the contents of IL-4 as well as IL-5 were rather higher than those in group B and C. It is evident from the above observations that IL-18 can effectively inhibit the asthmatic inflammatory cells in BALF with an imbalance of the Thl/Th2 cytokines, thus offer- ing the experimental basis for the clinical application of IL-18 in the prevention and treatment of asthma.