非髓源性与髓源性细胞Toll样受体4在小鼠肺缺血再灌注损伤中的作用

Role of Toll-like receptor 4 in non-medullary and medullary cells in lung ischemia-reperfusion injury in mice

目的 评价非髓源性与髓源性细胞Toll样受体4（TLR4）在小鼠肺缺血再灌注损伤中的作用.方法 健康雄性非髓源性细胞TLR4＋/＋/髓源性细胞TLR4＋/＋（WT/WT）小鼠、非髓源性细胞TLR4-/-/髓源性细胞TLR4-/-（KO/KO）纯合体小鼠、非髓源性细胞TLR4＋/＋/髓源性细胞TLR4-/-（WT/KO）和非髓源性细胞TLR4-/-/髓源性细胞TLR4＋/＋（KO/WT）杂合体小鼠各10只,6-8周龄,体重20-25 g.采用阻断左肺门60 min,再灌注240 min的方法制备小鼠肺缺血再灌注损伤模型.于再灌注240 min时采集股动脉血行血气分析,计算氧合指数（PaO2/FiO2）,随后处死小鼠取肺组织称湿重（W）,烘干后称干重（D）,计算W/D比值,光镜下观察肺组织病理学结果,并进行肺损伤评分,采用ELISA法检测髓过氧化物酶（MPO）活性、TNF-α、IL-1β和IL-6的含量.结果 与WT/WT型小鼠比较,WT/KO、KO/WT和KO/KO型小鼠PaO2/FiO2依次升高,肺损伤评分、W/D比值、MPO活性、TNF-α、IL-1β和IL-6含量依次降低（P〈0.05）.结论 非髓源性细胞较髓源性细胞TLR4在小鼠肺缺血再灌注损伤中发挥更重要的作用.

Objective To evaluate the role of Toll-like receptor 4 （TLR4） in non-medullary andmedullary cells in lung ischemia-reperfusion （I/R） injury in mice.Methods Ten healthy male TLR4＋/＋ in non-medullary cells/TLR4＋/＋ in medullary cells （WT/WT） mice,10 TLR4-/-in non-medullary cells/ TLR4-/-in medullary cells （KO/KO） homozygote mice,10 TLR4＋/＋ in non-medullary cells/TLR4-/-in medullary cells （WT/KO） mice,and 10 TLR4-/-in non-medullary cells/TLR4＋/＋ in medullary cells （KO/WT） heterozygote mice,aged 6-8 weeks,weighing 20-25 g,were used in the study.Lung I/R was induced by occlusion of the left hilum for 60 min followed by 240 min of reperfusion in anesthetized mice.Blood samples were obtained from the femoral artery at 240 min of reperfusion for blood gas analysis,and the oxygenation index （PaO2/FiO2） was calculated.The animals were then sacrificed and lung tissues were immediately removed for determination of wet/dry weight ratio,myeloperoxidase activity and contents of tumor necrosis factor-alpha,interleukin-1beta （IL-1β） and IL-6 （by enzyme-linked immunosorbent assay） and for microscopic examination of the pathological changes of lungs which were scored.Results Compared with WT/WT mice,the oxygenation index was significantly increased in sequence,and lung injury scores,wet/dry weight ratio,myeloperoxidase activity and contents of tumor necrosis factor-alpha,IL-1β and IL-6 were decreased in sequence in WT/KO,KO/WT and KO/KO mice （P〈0.05）.Conclusion TLR4 in non-medullary cells plays a rnore important role in lung I/R injury than that in medullary cells of mice.