LPS致大鼠急性肺损伤TLR4的表达及蓝桉油的影响

目的:观察正常大鼠气道TLR4的分布,LPS对大鼠气道TLR4分布以及蓝桉油对TLR₄表达的影响。方法:气管内注入LPS复制大鼠急性肺损伤模型,观察72 h后的病理变化、支气管肺泡灌洗液中细胞总数的变化、免疫组织化学特点以及蓝桉油的影响。结果:免疫组化结果显示TLR₄在正常组大鼠气道内有广泛分布。急性肺损伤组大鼠支气管肺泡灌洗液细胞总数明显增高,病理结果显示支气管、肺内炎症程度均明显高于正常组,免疫组化结果显示主支气管和肺内细支气管上皮细胞内TLR₄表达明显增强。蓝桉油300 mg.kg^-1组支气管肺泡灌洗液中白细胞总数明显低于急性肺损伤组,病理结果显示气管和主支气管的炎症程度明显减轻,免疫组化提示肺内细支气管上皮细胞内TLR4的表达量减少。结论:TLR₄在大鼠气道内广泛分布,LPS刺激可使TLR4的表达增强,蓝桉油可降低由LPS引起的肺内细支气管上皮细胞内TLR₄表达的增高。

The expression of TLR4 in rat acute lung injury induced by lipopolysaccharide and the influence of Eucalyptus globulus oil

Objective: To observe the distribution of toll-like receptor 4(TLR₄) in rats' respiratory tract.To study the influence of LPS and Eucalyptus globulus oil on the distribution of TLR₄.Method: The Sprague-Dawley rats were intratracheally instilled with lipopolysaccharide(LPS,2 mg·kg^-1 per day) for two days to induce acute lung injury.The rats were sacrificed at 72 hours after LPS instillation.Lung morphology was studied.Leukocytes in Bronchoalveolar lavage fluid(BALF) were measured and TLR₄ were detected by immunohistochemistry.Result: The result of immunohistochemistry showed that TLR₄ distributed widely in common rats' respiratory tract.In the group of acute lung injury,the number of leucocyte in BALF was increased apparently,the inflammation in bronchus and bronchioles was more apparently than that of the control group in morphology.And the expression of TLR₄ was reinforced in main bronchus and bronchioles.In the group of E.globules oil(300 mg·kg^-1),the leucocyte number was decreased apparently in BALF,the inflammation was lightened and the expression of TLR₄ decreased as compared with the group of models.Conclusion: The expression of TLR₄ distributes widely in rats' respiratory tract.The stimulation of LPS can reinforce the expression of TLR₄.The E.globules oil can reduce the increase of TLR₄ induced by LPS in bronchioles.