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目的:研究不同剂量脂多糖(LPS)通过诱导肺泡巨噬细胞(AM)Toll样受体4(TLR4)的高表达,探讨其对哮喘小鼠肺部炎症的影响。方法:BALB/c小鼠随机分为哮喘模型组(OVA)A,低剂量LPS处理组(0.1mg/LLPS+OVA)B,高剂量LPS处理组(100mg/LLPS+OVA)C,对照组(生理盐水)D。用卵白蛋白(OVA)致敏与激发建立小鼠哮喘模型;酶联免疫吸附试验(ELISA)检测各组小鼠支气管肺泡灌洗液(BALF)上清中IL-4、IL-5、IL-13和IFN-γ的含量,实时荧光定量PCR法测定AM的TLR4的表达,光镜观察肺组织病理变化。结果:与A组相比较,B组BALF上清中IL-4、IL-5和IL-13的水平显著增高(P<0.05),而IFN-γ差异无统计学意义(P>0.05),C组BALF上清中IL-4、IL-5和IL-13的水平显著降低,IFN-γ显著增高(P<0.05);与A组相比,B组与C组AM的TLR4mRNA表达均明显增高(P<0.05),两组间差异无统计学意义;光镜下,A组支气管黏膜下水肿,黏液腺增生,可见大量以嗜酸性粒细胞为主的炎症细胞浸润。B组与C组上述情况未见减轻,并出现肺泡腔及间质充血,中性粒细胞等大量的炎症细胞浸润,D组管腔内无黏液栓,气道周围无炎症细胞浸润,肺泡壁结构完整。结论:低剂量LPS(0.1mg/L)诱导哮喘小鼠AM的TLR4高表达,使肺部炎症加重,而高剂量LPS(100mg/L)可能会减轻变态反应症状。
AIM: To investigate the effects of different doses of lipopolysaccharide (LPS) on lung inflammation in asthmatic mice by inducing the overexpression of TLR4 in the alveolar macrophages (AM). Methods: BALB / c mice were randomly divided into three groups: asthma model group (A), low dose LPS treatment group (0.1mg / LLPS + OVA) B, high dose LPS treatment group Saline) D. The mouse asthma model was induced by ovalbumin (OVA) sensitization and challenge. The levels of IL-4, IL-5 and IL-6 in the supernatant of bronchoalveolar lavage fluid (BALF) were detected by enzyme-linked immunosorbent assay (ELISA) 13 and IFN-γ, the expression of TLR4 in AM was detected by real-time fluorescence quantitative PCR, and pathological changes of lung were observed with light microscope. Results: Compared with group A, the levels of IL-4, IL-5 and IL-13 in BALF supernatant of group B were significantly increased (P <0.05), while the difference of IFN-γ was not statistically significant The levels of IL-4, IL-5 and IL-13 in BALF supernatants were significantly decreased and IFN-γ significantly increased in group C (P <0.05). Compared with group A, the expression of TLR4 mRNA in AMs in groups B and C were significantly increased (P <0.05). There was no significant difference between the two groups. Under light microscope, bronchial submucosal edema and mucous gland hyperplasia in group A showed a large number of inflammatory cells infiltrating with eosinophils. There was no alleviation of the above conditions in Group B and Group C, and a large number of infiltration of inflammatory cells such as alveolar cavity and interstitial hyperemia and neutrophil appeared. No mucus plug was found in Group D, infiltration of inflammatory cells around the airway, Structure is complete. CONCLUSION: The high expression of TLR4 in asthmatic mice induced by low dose LPS (0.1 mg / L) can aggravate lung inflammation, while the high dose LPS (100 mg / L) may reduce the symptoms of allergy.