IL-8和Eotaxin在哮喘大鼠中的表达及地塞米松的作用

Expression of IL-8 and Eotaxin in rat asthma model and role of dexmethasone

目的研究哮喘大鼠外周血、肺泡灌洗液(BALF)中白介素-8(IL-8)、嗜酸性粒细胞趋化因子(Eotaxin)水平和肺组织Eotaxin mRNA及蛋白表达及地塞米松(DXM)对其影响。方法 30只SD大鼠随机平均分为正常组、哮喘组、DXM组。以卵蛋白(OVA)致敏和激发建立大鼠哮喘模型,BALF行细胞计数和分类;ELISA法检测血、BALF中IL-8、Eotaxin水平;肺组织切片HE染色观察病理变化;采用实时荧光定量PCR和免疫组化检测肺组织Eotaxin mRNA及蛋白表达。结果哮喘大鼠BALF中白细胞总数,嗜酸性粒细胞、中性粒细胞、淋巴细胞百分比显著高于正常组(P<0.01);血清、BALF中IL-8、Eotaxin水平均显著高于正常组(P<0.01),DXM组明显低于哮喘组(P<0.05);哮喘组肺组织Eotaxin mRNA及蛋白的表达水平明显高于正常组(P<0.05,P<0.01),DXM组介于两组之间。结论 IL-8和Eotaxin参与了哮喘炎症过程,DXM可通过抑制其表达来减弱中性粒细胞和嗜酸性粒细胞的趋化与激活,这可能是DXM减轻哮喘炎症反应的作用机制之一。

Objective To investigate the expression of IL-8 and Eotaxin in peripheral blood,bronchoalveolar lavage fluid（BALF）,mRNA and protein expressions of Eotaxin in lung tissue of asthma rat,and observe the effection of IL-8 and Eotaxin on dexamethasone（DXM）.Methods Thirty SD rats were randomly divided into control group,asthma model group and DXM group.Asthma rat model was established by sensitization and stimulation with ovalbumin（OVA）.Cell differential counting was conducted in BALF.IL-8 and Eotaxin levels in serum and BALF were detected by enzyme linked immunosorbent assay（ELISA）.The lung tissue slices were stained with HE.The mRNA and protein expressions of Eotaxin in lung tissue were measured with real-time fluorescent quantitative PCR and immunohistochemical techniques.Results Total white blood cell number,the percentage of eosinophils,neutrophils and lymphocytes in BALF of asthma group were significantly higher than those in control group（P0.01）;The expression of IL-8,Eotaxin in serum and BLAF of asthma group were increased than those in control group（P0.01）,which was descreased in dexamethasone treated group than those in asthma group（P0.05）.The mRNA and protein expressions of Eotaxin in lung tissue of asthma group were higher than those both in control group and asthma group（P0.05,P0.01）.Conclusions IL-8 and Eotaxin are involved in inflammation of asthma,and dexmethasone may inhibit the expression of IL-8 and Eotaxin to relieve aggregation and activation of neutrophil and eosinophil.which may be one mechanism of dexmethasone to attenuate inflammation of asthma.