致敏大鼠脑皮层和肺气道中干扰素—γ和白介素—4相关性的变化

目的:探讨致敏大鼠抗原攻击后脑皮层和肺气道中干扰素-γ(IFN-γ)和白介素-4(IL-4)出现的相关性变化.方法:观察致敏大鼠吸入抗原诱导的支气管肺灌洗液(BALF)和肺组织切片炎症变化,用ELISA法测定BALF和脑皮层IFN-γ和IL-4水平变化.结果:抗原攻击组BALF中的炎症细胞数目明显高于对照未攻击组(P<0.05).地塞米松(DXM,0.5mg/kg,ip)明显减少BALF中的白细胞总数,几乎完全抑制嗜酸性粒细胞(EOS)和淋巴细胞的聚集,但增加中性粒细胞数目.抗原攻击组的组织学检查积分(EOS浸润、粘膜水肿和上皮损伤)也明显高于对照未攻击组(P<0.05).DXM(0.5 mg/kg,ip)减少支气管和细支气管的EOS数目,改善粘膜水肿和上皮损伤.致敏大鼠抗原攻击后,BALF中的IFN-γ水平降低伴随IL-4升高导致了IFN-γ/IL-4比例下降.与此同时,脑皮层匀浆中也出现相似的改变.DXM(0.5mg/kg,ip)能反转BALF和脑皮层匀浆中的IFN-γ/IL-4比例下降.结论:致敏大鼠抗原攻击后脑皮层和肺气道中的IFN-γ和IL-4出现相关性变化.

Correlative changes of interferon-gamma and interleukin-4 between cortical layer and pulmonary airway of sensitized rats

AIM: To explore correlation of T helper 1 (Th1) and Th2 cytokine between the cortical layer and pulmonary airway in ovalbumin-induced rat asthma model. METHODS: Aerosol antigen-induced changes of inflammation in bronchoalveolar lavage fluids (BALF) and pulmonary histologic section in sensitized rats were investigated. Changes of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in BALF and cortical layer homogenates were determined by ELISA. RESULTS: The number of inflammatory cells in BALF in antigen challenged group was significantly higher than control group (P <0.05). Dexamethasone (DXM, 0.5 mg/kg, ip) markedly reduce total leukocyte numbers in BALF, and almost completely inhibited eosinophil, lymphocyte accumulation. The score of histological examination (eosinophil infiltration, mucous edema and epithelial lesion) in antigen challenged group was significantly higher than control group (P <0.05). DXM (0.5 mg/kg, ip) reduced the numbers of eosinophils and improved mucous edema and epithelial lesion of bronchi and bronchioles. In addition, our results demonstrated decreased IFN-gamma level accompanied by increased IL-4 level that resulted in a decreased IFN-gamma/IL-4 ratio in the BALF after the sensitized rats were challenged with aerosol antigen. Meanwhile, there was a similar change of IFN-gamma and IL-4 in cortical layer homogenates. DXM (0.5 mg/kg, ip) could reverse IFN-gamma/IL-4 ratio in the BALF and cortical layer homogenates in the model. CONCLUSION: The results showed a significant interplay changes of Th1 and Th2 cytokine between central nervous system and pulmonary airway in the asthmatic inflammatory model.