骨桥蛋白对脂多糖致急性肺损伤大鼠IFN-γ和IL-4表达的影响

目的：观察骨桥蛋白（OPN）对脂多糖（LPS）所致急性肺损伤（ALI）大鼠干扰素-γ（IFN-γ）、白细胞介素-4（IL-4）表达的影响。方法：将56只雄性SD大鼠随机分为对照组8只、ALI组24只、干预组24只,其中ALI组和干预组2、4、8h各8只。对照组经尾静脉注射生理盐水1ml,ALI组和干预组经尾静脉注入LPS液1ml（含LPS 6mg/kg）,5min后干预组再尾静脉注入抗OPN抗体（1∶32）0.5ml,而对照组和ALI组注射生理盐水0.5ml。对照组4h处死大鼠,而ALI组和干预组分别在2、4、8h处死大鼠各8只,检测支气管肺泡灌洗液（BALF）中性粒细胞数（PMN）、肺组织病理学改变和ALI评分;酶联免疫吸附实验（ELISA）测定大鼠血清IFN-γ、IL-4水平。逆转录-聚合酶联反应（RT-PCR）检测肺组织IFN-γ和IL-4 mRNA表达。结果：BALF中PMN数、ALI评分：ALI组2、4、8h较对照组相同时间点明显升高（P〈0.01）,而干预组在相同时间点较ALI组降低（P〈0.05）。ALI组2、4、8h血清IL-4水平和肺组织IL-4 mRNA表达均较对照组明显升高（P〈0.01）,但干预组与同时间点ALI组比较有显著升高（P〈0.05）。ALI组2、4、8h血清IFN-γ水平和肺组织IFN-γmRNA表达、血清IFN-γ/IL-4比值和肺组织IFN-γmRNA/IL-4 mRNA比值较对照组同时间点明显升高（P〈0.01）,但干预组则较ALI组同时间点明显降低（P〈0.05）。结论：OPN可促进LPS所致ALI大鼠IFN-γ表达而抑制IL-4表达,加剧IFN-γ/IL-4失衡,促进PMN在肺内聚集,加重LPS所致大鼠ALI。

THE INFLUENCE OF OSTEOPONTIN ON EXPRESSION OF INTERFERON-GAMMA AND INTERLEUKIN-4 IN ACUTE LUNG INJURY RATS INDUCED BY LIPOPOLYSACCHARIDE

Objective：To investigate the influence of osteopontin（OPN） on the expression of interferon-gamma（IFN-γ） and interleukin-4（IL-4） in acute lung injury（ALI） rats induced by lipopolysaccharide（LPS）.Methods： 56 male SD rats were randomly divided into control group（8 rats）,ALI group（24 rats） and intervention group（24 rats）.Control group was injected with 1ml normal saline（NS） via caudal vein.ALI group and intervention group were injected with 1ml LPS solution（containing LPS 6mg/kg） via caudal vein.5 minutes later,intervention group was injected with 0.5ml anti-OPN antibody（1∶32） while control group and ALI group were injected with 0.5ml NS in the same way.8 rats in ALI group were killed at 2,4 and 8h respectively,while 8 rats in control group were killed at 4h.The number of neutrophile granulocyte（PMN） in bronchoalveolar lavage fluid（BALF）,pathological changes of the lung tissue and ALI score were examined.The level of IFN-γ and IL-4 in serum was detected by ELISA at 2,4 and 8h,the expression of IFN-γ and IL-4 mRNA in lung tissue was determined by RT-PCR at the same time points.Results： The number of PMN and ALI score in ALI group at 2,4 and 8h was higher than that in control group（P〈0.01） and intervention group at the same time points（P〈0.05）.The level of IL-4 in serum and the expression of IL-4 mRNA in lung tissue of ALI group were significant high compared with control group（P〈0.01）,but were lower than those in intervention group at the same time points（P〈0.05）.The level of IFN-γ and the ratio of IFN-γ/IL-4 in serum,the expression of IFN-γ mRNA and the ratio of IFN-γ mRNA/IL-4 mRNA in lung tissue increased significantly in ALI group than those in control group（P〈0.01） and intervention group（P〈0.05）.Conclusion： OPN can promote the expression of IFN-γ,reduce the expression of IL-4,and aggravate the imbalance of IFN-γ/IL-4 and pathology changes including boosting the lung filtration of PMN of ALI rats induced by LPS.