中文摘要：

目的研究脓毒症中胞外组蛋白水平的变化及其对内皮细胞毒性作用机制。方法2010年1月至2014年12月上海儿童医学中心PICU婴儿脓毒症病例130例，根据脓毒症诊断标准分为脓毒症组（51例）和严重脓毒症组（79例），同期健康体检儿童作为对照组（108例）。根据28d病死率将严重脓毒症组分为生存组（45例）和死亡组（34例）两个亚组。测定各组血清组蛋白浓度，并分析其与疾病严重程度及预后的相关性。培养人脐静脉内皮细胞（human umbilical vein endothelial cell，HUVEC），用小牛胸腺组蛋白（calf thymus histone，CTH）以不同浓度（0、50、100、200及300μg/ml）及不同时间（200μg／ml CHT处理0、5、15、30、45、60min）处理后，用流式细胞仪检测细胞存活率，以电镜观察细胞的形态学变化，以Westernblot检测核因子（nuclear factor，NF）-κB及丝裂原活化蛋白激酶（mitogen—activa—ted protein kinase，MAPK）信号通路中NF—KB抑制因子IKB以及磷酸化p38／p38表达，以ELISA检测肿瘤坏死因子-α和白细胞介素-6表达水平。结果严重脓毒症组患儿血清组蛋白水平（19．17±10．20）显著高于脓毒症组（2．29±1．00）及对照组（0．23±0．26）（P〈0．001），并且在严重脓毒症患儿中，死亡患儿血清组蛋白水平显著高于存活者（29．47±5．99VS．10．94±2．68，P〈0．001）。体外实验发现，随CTH处理时间或者剂量增加，HUVEC的生存率逐步下降。扫描电镜和透射电镜观察CTH处理后HUVEC发现细胞膜破坏现象。组蛋白可以激活NF—κB及MAPK通路，并释放肿瘤坏死因子-α、白细胞介素-6等炎性因子。结论在脓毒症患者中胞外组蛋白浓度与疾病严重程度相关。CTH可以呈剂量依赖性及时间依赖性诱导HUVEC死亡。胞外组蛋白在脓毒症中通过对血管内皮细胞的毒性作用，介导疾病进程，而这一毒性作用与破坏内皮细胞细?

英文摘要：

Objective To investigate the change of extracellular histone level as well as the mechanism of the cytotoxicity of extracellular histones on vascular endothelial cell in sepsis. Methods Septic children admitted to PICU in Shanghai Children＇s Medical Center between January 2010 and December 2014 were included in the present study. According to the diagnostic criteria of sepsis, the patients were divided into the sepsis group （51 cases） and the severe sepsis group （79 cases）, with healthy children as the control group （108 cases）. Patients in the severe sepsis group were further divided into the survival group（45 cases） and the non-survival group （ 34 cases ） based on 28-day morality. The plasma concentration of extracellular histones in these children was determined and its correlation with the severity of sepsis was analyzed. Human umbilical vein endothelial cells（HUVECs） were incubated with calf thymus histone（CTH） at various con-centrations（0,50,100,200 and 300 pog/ml） or different time periods（200 μg/ml,0,5 ,15 ,30,45 and 60 minutes）. The treated cells were subject to flow cytometer to measure the cell survival rate and scanning/transmission electron microscopy to observe their morphological changes. Western blot was used to detect the expression of IKB and phosphor-p38/p38 in nuclear factor （NF）-KB and mitogen-activated protein kinase （MAPK） signaling pathways ,while ELISA was used to determine the levels of tumor necrosis factor-α and interleukin-6. Results The levels of circulating histones in the septic children（2. 29 ± 1.00） and severe septic children （ 19. 17 ± 10. 20 ） were significantly higher than that of healthy controls （ 0. 23 ± 0. 26 ） （ P 〈 0. 001 ）, and the histone levels in the severe septic children were even higher（ P 〈 0. 001 ）. Among the children diagnosed as severe sepsis,the level of circulating histories in the non-survivors was significantly higher than that in the survivors（29. 47 ±5.99 vs. 10. 94 ±2. 68 ,P