摘要目的 评价Toll样受体4(TLR4)在机械通气致糖尿病小鼠肺毛细血管通透性增加中的作用.方法 选择雄性野生型小鼠C3H/HeN和TLR4基因突变型小鼠C3H/HeJ各28只,8～ 10周龄,体重20 ～ 25 g,腹腔注射链脲佐菌素150 mg/kg的方法制备糖尿病模型.采用随机数字表法,将2种小鼠各随机分为2组(n=14),假手术组(DS组)糖尿病小鼠行气管插管术自主呼吸4h;机械通气组(DM组)糖尿病小鼠进行机械通气4h,吸入氧浓度50％,通气频率70次/min,潮气量15 ml/kg,PEEP 2cmH2O.自主呼吸或机械通气4h时采集颈动脉血样行血气分析,记录PaO2和PaCO2,收集血清,测定血清一氧化氮(NO)浓度.随后处死,取肺组织测定肺组织湿/干重比(W/D比值)、伊文思蓝(EB)含量,Western blot法测定小凹蛋白-1、内皮型一氧化氮合成酶(eNOS)和磷酸化内皮型一氧化氮合成酶(p-eNOS)的蛋白表达水平,计算p-eNOS/eNOS比值.结果 与DS组比较,DM组小鼠PaO2、PaCO2、p-eNOS/eNOS比值降低,肺组织W/D比值、EB含量、小凹蛋白-1表达水平明显升高(P＜0.05);与C3H/HeN小鼠比较,DM组C3H/HeJ小鼠肺组织W/D比值、EB含量和小凹蛋白-1表达水平明显降低,p-eNOS/eNOS比值和血清NO浓度升高(P＜0.05),PaO2和PaCO2差异无统计学意义(P＞0.05).结论 TLR4通过与小凹蛋白-1有效结合,减少NO生物利用度,增加糖尿病小鼠机械通气后肺毛细血管通透性.

abstractsObjective To evaluate the role of Toll-like receptor 4 (TLR4) in mechanical ventilationinduced increase in pulmonary capillary permeability in diabetic mice.Methods Two types of mice,aged 8-10 weeks,weighing 20-25 g,were used in this study:free wild type mice (C3H/HeN) and TLR4 gene mutation type (C3H/HeJ).Diabetes was induced by intraperitoneal streptozotocin 150 mg/kg (in citric acid buffer solution 0.1 mol/L) and confirmed by blood glucose level ＞ 16 mmol/L.Each type of diabetic mice was randomly divided into 2 groups (n =14 each):group diabetes + sham operation (group DS) and group diabetes + mechanical ventilation (group DM).The animals were anesthetized with intraperitoneal ketamine,midazolam and atropine.Tracheal intubation was performed and the animals kept spontaneous breathing in group DS.The animals were mechanically ventilated (FiO2 50％,RR 70 bpm,VT 15 ml/kg,PEEP 2 cmH2O) for 4 h in group DM.Arterial blood samples were obtained at 4 h of ventilation for blood gas analysis,PaO2 and PaCO2 were recorded,and NO concentration in the serum was measured.Then the animals were sacrificed and the lungs were removed for determination of W/D lung weight ratio (W/D ratio),content of evans blue (EB),and expression of caveolin-1,endothelial nitric oxide synthase (eNOS) and phosphor-eNOS (p-eNOS) (by Western blot).The ratio of p-eNOS/eNOS was calculated.Results Compared with group DS,PaO2,PaCO2 and p-eNOS/eNOS ratio were significantly decreased,and W/D ratio,EB content and caveolin-1 expression were increased in group DM (P ＜ 0.05).Compared with C3H/HeN mice,W/D ratio,caveolin-1 expression and EB content were significantly decreased,peNOS/eNOS ratio and serum NO concentrations were increased (P ＜ 0.05),and no significant changes in PaO2 and PaCO2 were found in C3H/HeJ mice in group DM (P ＞ 0.05).Conclusion TLR4 increases the pulmonary capillary permeability after mechanical ventilation in diabetic mice through effectively combining with caveolin-1 and reducing NO bioavailability.