【作者】 陈继红；

【导师】 张建龙；

【作者基本信息】 新疆医科大学 ， 劳动卫生与环境卫生， 2008， 博士

【摘要】 第一部分多器官功能障碍综合征动物模型的建立目的:复制符合多器官功能障碍综合征(multiple organ dysfunction syndrome, MODS)发病因素,病理过程和临床特征的标准化动物模型。方法:15只雄性Beagle犬,体重14～16.3kg(由新疆医科大学实验动物中心提供)。实验前禁食24h,正常饮水。动物戊巴比妥钠30mg/kg静脉麻醉后,称重,固定,消毒,行气管插管术,管经口插入深26cm,插管成功后接呼吸机辅助呼吸,模式为容量控制通气(CMV),参数为潮气量15 ml/kg、呼吸频率为20～25次/min、呼气末正压(PEEP)2～3cmH2O;行右股动脉穿刺术,置入5F动脉留置针,连接心功能监护仪行血流动力学监测;行左股静脉穿刺术,置入7F导管用于持续静点戊巴比妥钠2～4mg/kg/h和留取血标本;分别采用左颈内静脉和右股静脉留置11F单针双腔导管建立血管通路,应用CVVHDF治疗。所有导管直接插入,切口行外科缝合。间断用肝素钠盐水冲导管预防凝血。留置导尿管,心电监护,监测肛温,必要时使用电热毯保持体温在38～39℃。术后30分钟,采用Wiggers法[1]造成失血性休克,维持平均动脉压(MAP)6.0-7.3kPa (45-54mmHg)之间1小时。休克终点,经颈静脉快速回输失血和两倍失血量的林格氏液。回输毕MAP和心排指数(CI)均能恢复至伤前水平。复苏12h后由静脉持续12h滴入内毒素(大肠杆菌O111B4内毒素,第二军医大学基础医学部微生物学教研室提供)1.5mg/kg。观察实验动物犬的症状、体征、生存率、脏器功能指标,如丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、血尿素氮(BUN)和血肌酐(Cr)与组织病理变化。结果:实验前MAP分别是114.2±13.2mmHg。造成失血性休克后MAP降至54.8±6.1mmHg,复苏后恢复至正常90%左右。输入内毒素后,MAP呈进行性下降,明显低于实验前(P<0.01)。休克期PaO2和PaCO2降低,与伤前差别显著(P<0.05);输入内毒素后,PaO2呈进行性降低,PaCO2呈明显升高趋势。在MODS病变发展过程中,实验动物在二次打击后症状、体征与功能指标(ALT、AST、BUN及Cr)均发生明显变化,肝、肾等脏器病理损伤明显。结论:该模型的致伤因素、发病过程、临床特征及诊断标准都与临床典型的双相迟发MODS相似,是目前比较理想的和适用于临床防治研究的MODS动物模型。第二部分连续性血液透析滤过对多器官功能障碍综合症犬的组织病理及功能变化的影响目的:观察连续性血液透析滤过(CVVHDF)对多器官功能障碍综合征(MODS)犬重要器官功能和组织病理的影响,探讨CVVHDF治疗MODS的可能机制。方法:15只Beagle犬采用失血性休克+复苏灌注+内毒素血症复制MODS模型[2],随机分为CVVHDF组(n=8)和MODS组(n=7),CVVHDF组在内毒素注射完毕后给于CVVHDF治疗12小时,MODS组不给CVVHDF治疗。检测各时间点动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、肌酐(Cr)、血尿素氮(BUN)及血浆内毒素(LPS)的水平,同时观察两组动物肝、肾组织病理形态学改变。结果:CVVHDF组治疗过程中,MAP基本保持在正常水平,尤其在T5、T6及T7时间点显著高于MODS组(P<0.01);PaO2逐渐升高,与MODS组在T4、T5、T6及T7时间点相比相差显著(P<0.05);血清肌酐(Cr)、血尿素氮(BUN)及血浆内毒素(LPS)水平较MODS组降低(P<0.05)。伤后两组动物肝、肾组织均可见不同程度的充血、灶状与大片状坏死、出血及炎性细胞浸润。CVVHDF组器官病变较MODS组明显减轻。结论:连续性血液透析滤过能明显改善内毒素诱导的低血压,提高动脉血氧分压,有效清除血浆内毒素,改善肾功能,减轻肝、肾组织病理损害。第三部分连续性血液透析滤过对多器官功能障碍犬细胞因子的影响目的:观察连续性血液透析滤过(CVVHDF)对多器官功能障碍综合征(MODS)犬器官功能和细胞因子的影响,探讨CVVHDF治疗MODS的可能机制。方法:15只Beagle犬采用失血性休克+复苏灌注+内毒素血症复制MODS模型,随机分为CVVHDF组(n=8)和MODS组(n=7),CVVHDF组在内毒素注射完毕后给于CVVHDF治疗12小时,MODS组不给CVVHDF治疗。免疫组织化学分析两组肝、肾组织中IL-6、IL-10阳性蛋白表达。半定量逆转录-聚合酶链反应(RT-PCR)测定两组肝、肾组织中IL-6、IL-10 mRNA水平。ELISA方法检测血浆IL-6、IL-10浓度。结果:CVVHDF治疗开始后血浆IL-6、IL-10明显下降,在内毒素注射完毕后3h(T4)、6h(T5)、9h(T6)及12h(T7)时间点显著低于MODS组(P<0.01)。超滤液中能检测出IL-6,IL-6筛选系数(SC)为0.27±0.13。超滤液中未能检测出IL-10。免疫组织化学分析两组肝、肾组织中IL-6、IL-10阳性蛋白表达,在MODS组IL-6阳性蛋白表达水平显著增高,而在CVVHDF组IL-10阳性蛋白表达水平显著增高。应用半定量RT-PCR方法测定肝肾组织IL-6、IL-10 mRNA表达水平,在MODS组IL-6 mRNA表达水平显著高于正常水平和CVVHDF组(P<0.01),而在CVVHDF组IL-10mRNA表达水平显著高于正常水平和MODS组(P<0.01)。结论:CVVHDF能有效清除循环中细胞因子IL-6、IL-10,有助于重建机体免疫系统内稳状态。超滤液中能检测出IL-6,表明CVVHDF治疗通过对流机制可以有效清除血浆中的IL-6。超滤液中未能检测出IL-10,故可推理CVVHDF可能通过吸附而非超滤作用清除IL-10。更多还原

【Abstract】 Objective : To find a standardized animal model that would accurately imitateclinical features of multiple organ dysfunction syndrome (MODS).Methods: The study was approved by the Animal Care and Use Committee of Xinjiang Medical University. After a 24 hour fast, 15 male beagle dogs weighting 14 to 16.3 kg were anesthetized intravenously with pentobarbital sodium (30mg/kg). Instrumentation was performed in a sterile fashion with animals fixed in the supine position. Each animal was intubated with a 9-F cuffed endotracheal tube and ventilated at a tidal volume of 15ml/kg, a respiratory rate between 20 and 25 breaths/min, a positive end-expiratory pressure level of 2～3cmH2O. A 5-F catheter with multiple holes was inserted into the right femoral artery and advanced into the abdominal aorta for measurement of arterial pressure. A 7-F polyvinyl chloride catheter was inserted into the left femoral vein for continuous infusion of pentobarbital at 2 to 4 mg/kg/h and sampling of blood. A 11-F pulmonary artery catheter sheath was inserted into the right femoral vein to provide vascular access for CVVHDF. A second 11-F pulmonary artery catheter sheath was inserted into the left jugular vein and provided the return limb of the veno-venous circuit. All catheters were placed by direct cutdown and the wounds closed surgically. All catheters were flushed with heparinized saline to prevent clotting. A 14-F silastic catheter was inserted suprapubically into the bladder. Body temperature was monitored by a rectal thermistor and kept constant around 38～39℃using a heating blanket.After line insertion, once the animals had been hemodynamically stable for 30 minutes (heart rate change and blood pressure change<10%), they were subjected to hemorrhagic shock plus resuscitation and endotoxiemia to set up MODS model. Hemorrhagic shock was produced according to the method of Wigger. The dogs underwent withdrawal of blood through the right femoral vein with a syringe. MAP maintained about 6.7～7.3kPa for an hour. Following an hour observation period, the animals were resuscitated with intravenous infusion of Ringer’s solution at 2 times the shed blood volume and the shed blood to return the heart rate and blood pressure toward baseline values. After 12 hours of the resuscitation of hemorrhagic shock, Escherichia coli endotoxin (O111B4 lipopolysaccharide; Department of Microbiology, Second Military Medical University, Shanghai, China) was given via the femoral vein, in a dose of 1.5 mg/kg in 500 ml of normal saline infused over 12 hours. Symptoms and signs, survival rate, organ function parameters and pathological changes in main organs were observed in dogs.Results: The baseline mean values for MAP was 114.2±13.2 mmHg in MODS group. Note that MAP is lowest in animals receiving hemorrhagic shock, followed by a partial recovery during the next 12 hours. MAP after the start of endotoxin injection, in MODS group, was significantly lower than baseline. Mean PaO2 after the start of endotoxin injection was significantly lower than baseline. Mean PaCO2 at 21 and 24 hr after the start of endotoxin injection, in MODS group, was significantly higher than baseline.Plasma level of alanine aminotransferase(ALT)?aspartate aminotransferase(AST)?blood urea nitrogen(BUN) and creatinine(Cr) were increased and severe pathological lesions were observed in tissues of the liver and kidney .Conclusion: It was successful to reproduce the standard large animal model which was very similar in all respects to a delayed two phase MODS of human patients. The Effect of Continuous Veno-venous Haemodiafiltration on Major Organ Function and Histopathological Changes in a Canine Model for Multiple Organ Dysfunction SyndromeObjective: To study the influence of continuous veno-venous haemodiafiltration (CVVHDF) on major organ function and histopathological changes in MODS dogs.Methods : fifteen Beagle dogs were subjected to hemorrhagic shock plus resuscitation and endotoxemia to set up MODS model, then dogs were randomly divided into 2 groups: CVVHDF group (n=8) and MODS group without CVVHDF (n=7). CVVHDF was performed ahout 12 hours after endotoxin injection was finished in CVVHDF group. Blood samples were taken for evaluation of serum ALT, AST, Cr, BUN,LPS and blood gas. After a maximal observation period of 40 hours, animals were killed then liver and kidney were taken for pathologic observation.Results: The beneficial effect of CVVHDF on the hypotensive effect of MODS model, was particularly striking at 6h(T5), 9h(T6) and 12h(T7) after endotoxin injection (P<0.01). Mean PaO2 in CVVHDF groups at 3h(T4)?6h(T5)?9h(T6) and 12h(T7) after endotoxin injection was significantly higher than in MODS group(P<0.05). The levels of Cr, BUN and LPS were decreased significantly in the CVVHDF group compared with the MODS group (P<0.05). Different degrees of congestion?spotty and mass necrosis?bleeding and inflammatory cell infiltration were observed in the liver and kidney tissues.These changes were more severe in the MODS group than in the CVVHDF group.Conclusion: Our results suggest that treatment with CVVHDF effectively removed plasma LPS from the circulation, attenuated endotoxin-induced hypotension , improved arterial oxygenation and ameliorated morphologic changes of liver and kidney in dog MODS model. The Effect of Continuous Veno-venous Haemodiafiltration on Soluble Mediators in a Canine Model for the Multiple Organ Dysfunction SyndromeObjective: To study the influence of Continuous Veno-venous Haemodiafiltration (CVVHDF) on plasma cytokine levels in MODS dogs.Methods : fifteen Beagle dogs were subjected to hemorrhagic shock plus resuscitation and endotoxemia to set up MODS model, then dogs were randomly divided into 2 groups: CVVHDF group (n=8) and MODS group without CVVHDF (n=7). CVVHDF was performed ahout 12 hours after endotoxin injection was finished in CVVHDF group. Immunohistochemistry was performed to localise changes in expression of IL-6、IL-10 protein of kidney and liver tissues from dogs in MODS group and in CVVHDF group. Liver and kidney samples of the MODS and CVVHDF groups were immediately collected after the dogs were killed. Il-6 and IL-10 mRNA levels were quantified by semi-quantitative RT-PCR. IL-6 and IL-10 concentrations were measured by ELISA.Results: Serum levels of IL-6 and IL-10 were significantly decreased in the CVVHDF group at 3h(T4), 6h(T5), 9h(T6) and 12h(T7) after endotoxin injection (P<0.01), as compared with animals in the MODS group. IL-6 was detected in the ultrafiltrate, The sieving coefficients (SC) for IL-6 was 0.27±0.13. IL-10 could not be detected in the ultrafiltrate. Immunohistochemical analysis revealed the expression of IL-6 protein was lower and the expression of IL-10 protein was higher in kidney and liver tissues in the CVVHDF group compared with those in the MODS group. IL-6 mRNA levels in the MODS group were markedly higher than those in the normal control condition and the CVVHDF group (P<0.01). IL-10 mRNA levels in the CVVHDF group were statistically increased, as compared with those in the control condition and the MODS group (P<0.01)Conclusion: Our results suggest that treatment with CVVHDF effectively removed IL-6 and IL-10 from the circulation and potentially improved immunologic disorder, we postulated that there was a better clearance of IL-6 via the convective transport in CVVHDF. The removal of IL-10 by CVVHDF maybe predominantly due to adsorption rather than convective transport.更多还原