乙酰肝素酶对脓毒症肾小球内皮细胞糖萼的影响

Impact of heparanase on glomerular endothelium glycocalyx during sepsis

目的 观察乙酰肝素酶对脓毒症肾小球内皮细胞糖萼的影响,并探讨其预防措施.方法 C57BL/6小鼠给予脂多糖（LPS）或肿瘤坏死因子α（TNF-α）腹腔注射,1h后处死,镧示踪后透射电镜观察肾小球内皮细胞糖萼变化,Western印迹检测肾皮质的乙酰肝素酶蛋白表达;人肾小球内皮细胞用TNF-α作用1h,Western印迹检测乙酰肝素酶的活化蛋白变化.小鼠注射LPS同时给予肝素钠和肝素酶Ⅲ,电镜观察肾小球内皮细胞糖萼的变化;留取小鼠24 h尿液,检测各组尿白蛋白和尿肌酐,计算尿白蛋白-肌酐比值,进行比较.结果 镧示踪透射电镜显示,LPS组和TNF-α组肾小球内皮细胞糖萼均降解,而足细胞糖萼完整.小鼠注射LPS后1h开始,肾皮质乙酰肝素酶蛋白表达显著增高（P＜0.01）.TNF-α刺激人肾小球内皮细胞后乙酰肝素酶活化增加（P＜0.05）.小鼠注射LPS同时给予肝素钠抑制乙酰肝素酶,肾小球内皮细胞糖萼完整,尿白蛋白-肌酐比值显著低于LPS组（P＜0.05）;同时给予肝素酶Ⅲ使肾小球内皮细胞糖萼降解,尿蛋白-肌酐比值无改善,显著高于对照组（P＜0.01）.结论 脓毒症初期,TNF-α使肾小球内皮细胞的乙酰肝素酶表达和活化增加,肾小球内皮细胞糖萼降解,发生蛋白尿;抑制乙酰肝素酶能保护肾小球内皮细胞糖萼,减少尿蛋白.

Objective To observe the impact of heparanase on glomerular endothelium glycocalyx during sepsis and to investigate the prevention of glycocalyx injury.Methods C57/BL6 mice were injected with lipopolysaccharide （LPS） or tumor necrosis factor-α（TNF-o） and sacrificed one hour later.Glomerular endothelium glycocalyx traced with lanthanum was observed by transmission electron microscope（TEM）.Western blotting was used to observe heparanse protein expression of renal cortex tissue.Human renal glomerular endothelial cells （HRGECs） were stimulated with TNF-α and active heparanase protien expression was detected by Western blotting.Mice were administrated with heparin sodium or heparinase Ⅲ and renal endothelium glycocalyx was observed by TEM.Urine during twenty-four hours was collected to measure urinary albumin and creatinine.The ratio of albumin to creatinine was calculated and compared among groups.Results The glomerular endothelium glycocalyx of LPS group and TNF-α group was degradated and the one of podocyte was integrated.Renal cortex tissue heparanase protein expression was significantly increased since one hour after LPS injection （P 〈 0.01）.The protein expression of activited heparanase of HRGECs which were stimulated with TNF-α was increased （P 〈 0.05）.Administration of heparin sodium which could inhibit the activity of heparanase could prevent the glycocalyx form degradation.The ratio of urine albumin to creatinine of heparin sodium group was decreased compared with LPS group （P 〈 0.05） and the ratio of heparinase Ⅲ group was higher than control group（P 〈 0.01） as a result of degradation of glomerular endothelium glycocalyx.Conclusions During the early stage of sepsis,TNF-α can induce glomerular endothelium heparanase to increase and active,and consequently the glycocalyx is degradated which leads to albuminuria.Inhibition of heparanase can protect glomerular endothelium glycocalyx and prevent albuminuria.