【作者】 罗鹏；

【导师】 齐清会；

【作者基本信息】 大连医科大学 ， 外科学， 2014， 硕士

【摘要】 背景：多器官功能障碍综合征（multiple organ dysfunction syndrome，MODS）是指当机体遭受到严重的烧伤、创伤、中毒、感染和休克等伤害后，同时或序贯发生两个或两个以上脏器功能失常最终衰竭的临床综合征。MODS不是独立的疾病，其发病原因多，进展快，病理机制复杂。患腹部外科急症患者一旦发生MODS，预后差，死亡率极高[1]。一般情况下，当机体发生感染或组织损伤时，局部的炎症反应对清除细菌和修复损伤组织是十分必要的，并且具有保护性。但若炎症反应异常放大，就会对机体产生损伤作用，导致自身细胞坏死、组织和器官功能障碍，最终导致MODS的发生[2]。因此，从本质上来说，MODS是机体炎症反应失控导致的不良结果。而感染是炎症反应的促发因素，是MODS的根本原因。目前研究观点认为，胃肠道是MODS发生的关键部位。肠道是人体内最大的“储菌库”和“内毒素库”。严重的损伤，如大面积烧伤、大手术、中毒、感染、严重的创伤和休克等，可导致消化道粘膜屏障损伤。胃肠粘膜发生糜烂、溃疡，同时胃肠道内的细菌滋生、菌群失衡，病菌与内毒素进入血液循环系统导致菌血症、内毒素血症甚至败血症。机体的炎症反应过度放大，发生全身炎症反应综合征（systemic inflammatory response syndrome，SIRS）和MODS[3]。因此胃肠道在MODS发生发展中具有重要地位。危重症患者的预后和胃肠运动功能恢复程度密切相关，促进消化道运动功能恢复是救治危重症患者的关键[4]。目的：研究对象为Wistar大鼠，建立细菌性腹膜炎致MODS大鼠模型，测定大承气汤干预前后的MODS大鼠模型小肠平滑肌组织中的线粒体凋亡途径相关蛋白Bcl-2、Bax，和NF-κB、COX-2蛋白的表达和分布变化。探讨MODS致消化系统运动障碍的病理生理机制，和大承气汤促进MODS胃肠动力恢复的机理。方法： Wistar大鼠100只（健康成年清洁级），雌雄大鼠各50只，体重200-250g。随机分组：对照组（20只）、MODS组（40只）和大承气汤组（40只）。对照组大鼠腹腔内注射1ml生理盐水/只；MODS组和大承气汤组大鼠腹腔内注射1ml E.coli.混悬液/只，建立细菌性腹膜炎致MODS模型。其中大承气汤组每只大鼠在造模前2天均给予大承气汤灌胃，每次1ml/100g，2次/日。造模24小时后取存活大鼠上段小肠组织，予甲醛固定、石蜡包埋。采用免疫组织化学染色法观察和检测大鼠小肠平滑肌组织中线粒体凋亡相关蛋白Bcl-2、Bax和NF-κB、COX-2蛋白的表达和分布情况。结果：大体标本与对照组相比，MODS组大鼠胃肠梗阻症状明显。大承气汤组大鼠胃肠梗阻情况较MODS组明显减轻，胃肠蠕动功能基本正常。免疫组化法检测①线粒体凋亡途径相关蛋白Bcl-2、Bax检测结果：与对照组比较，MODS组大鼠小肠平滑肌组织中Bcl-2蛋白表达明显减少(P＜0.05)，分布稀疏，而Bax蛋白表达明显增多(P＜0.05)，分布密集。同MODS组比较，发现大承气汤组大鼠小肠肌层组织中的Bax蛋白表达明显减少(P＜0.05)，Bcl-2蛋白表达明显增多(P＜0.05)，分布密集。②NF-κB、COX-2蛋白检测结果：与对照组比较，MODS组大鼠小肠平滑肌组织中的NF-κB和COX-2蛋白的表达明显增多(P＜0.05)，分布密集。同MODS组比较，发现大承气汤组大鼠小肠平滑肌组织中的NF-κB和COX-2蛋白的表达明显降低(P＜0.05)，且分布疏松。结论：①细菌性腹膜炎致MODS大鼠胃肠梗阻症状严重，死亡率较高；大承气汤可以促进消化系统的蠕动，使胃肠梗阻症状明显缓解，降低MODS大鼠的死亡率。②MODS大鼠小肠肌层中Bax蛋白表达较对照组明显增多，而Bcl-2蛋白表达明显减少，线粒体凋亡途径激活导致小肠平滑肌细胞凋亡，造成胃肠动力障碍；大承气汤可以增加MODS大鼠小肠平滑肌细胞中的Bcl-2蛋白表达，减少Bax蛋白表达，通过抑制小肠平滑肌细胞线粒体凋亡途径从而保护小肠平滑肌，恢复消化系统的蠕动。③MODS胃肠动力障碍可能与小肠平滑肌NF-κB和COX-2蛋白的表达增加密切相关；大承气汤可以减少NF-κB和COX-2蛋白的表达，抑制炎症反应的加剧和凋亡信号的放大效应，保护MODS大鼠小肠平滑肌，促进胃肠动力的恢复。更多还原

【Abstract】 Background: Multiple organ dysfunction syndrome (MODS) can be induced byserious damage, infection, major operation, hypoperfusion and shock, in acute illpatients. In MODS, more than two organs dysfunction simultaneously or successively.MODS is the main cause of death in patients undergoing acute abdominal surgery,with many causes, complex pathological mechanism, and high mortality rate. Undernormal condition, local inflammatory reaction is very necessary to the body withinfection or damaged tissue, playing protective effect by removing bacteria andrepairing damaged tissues. But if inflammation is abnormal amplification or out ofcontrol, inflammation will make cell death, tissue and organ dysfunction or injury,producing harmful effect to the body, and finally leading to the occurrence of MODS.Therefore, in essence, MODS is the result of uncontrolled inflammation, and infectionis the precipitating factor of the inflammatory response, and also the root cause ofMODS. In the current study view, the gastrointestinal tract is the key part of MODS.When the peristaltic function of gut with plenty of bacteria and endotoxin is damaged,bacteria and endotoxin translocate into the circulation, causing excessiveinflammatory response. These make systemic inflammatory response syndrome (SIRS) and MODS occur. Therefore, the gastrointestinal tract plays a very important role inMODS development. The gut is not only the target organ of MODS, but also theinitiating organ of MODS. The function of gut is an important prognosis index ofcritically ill patients. Protecting and promoting gastrointestinal motor functioneffectively is considered the key to prevent and treat MODS.Objective: To observe the expression and distribution of mitochondrial apoptosisrelated protein Bcl-2and Bax, and NF-κ B and COX-2proteins of the small intestinalsmooth muscle of MODS rats, and the intervention effects of Da Cheng QiDecoction (DCQD);to study the mechanism of gastrointestinal motility disordersunder MODS station, and also the effect of DCQD on MODS.Methods: One hundred healthy adult Wistar rats of clean grade, half male andhalf female, weight200-250g. Rats were randomly divided into three groups: controlgroup with20rats，MODS group with40rats, and DCQD group with40rats. Themodel of MODS was established according to previous experiments. Briefly, understerile condition, MODS and DCQD group rats were intraperitoneal injection of onemillilitre Escherichia coli suspension of8×108cfu/ml. Control group wereintraperitoneal injection of one milliliter physiological saline. The rats in DCQDgroup rats in the modeling of before two days were treated with DCQD orally, oneml/100g each time, twice a day. One day after injection, the proximal small intestinewas used in the experiment. To observe and detect of the expression and distributionof mitochondrial apoptosis related protein Bcl-2, Bax, and NF-κ B, COX-2proteins insmall intestinal smooth muscle tissue in rats using immunohistochemical staining.Results: Observation of mitochondrial apoptosis related protein Bcl-2and Bax:Compared with control group, the expressions of Bax in MODS group was increasedsignificantly (P<0.05), and Bcl-2was decreased significantly (P<0.05). Comparedwith MODS group, the expressions of Bax in DCQD group was reduced significantly(P<0.05), and Bax was decreased significantly (P<0.05).Observation of NF-κ B, COX-2proteins: Compared with control group, theexpressions of NF-κ B, COX-2proteins in MODS group was increased significantly(P<0.05). Compared with MODS group, the expressions of Bax in DCQD group was reduced significantly (P<0.05).Conclusions: Gastrointestinal obstruction symptom was serious in rats withMODS induced by bacterial peritonitis, and motility function was damaged. DCQTcould obviously alleviate gastrointestinal obstruction symptoms, promotegastrointestinal motor function recovery, thus reducing the mortality of rats in MODS.Under MODS condition, the expression of Bax proteins in small intestinalsmooth muscle of rats with MODS was significantly increased than the control group,and the expression of Bcl-2protein was significantly reduced. These mademitochondrial apoptotic pathway activate, leading apoptosis of small intestinalsmooth muscle, and resulting in gastrointestinal motility disorders. DCQD couldinhibit mitochondrial apoptotic pathways by increasing the expression of Bcl-2protein in small intestinal smooth muscle of rats with MODS, and decreasing theexpression of Bax protein, therefore could promote the recovery of gastrointestinalmotility.Gastrointestinal motility disorders in MODS might be associated the increasedexpression of NF-κ B and COX-2proteins in small intestinal smooth muscle of rats.DCQD could inhibit the inflammatory response and apoptosis signal pathway byreducing the expression of NF-κ B and COX-2proteins, to protect small intestinalsmooth muscle of rats with MODS, and promote gastrointestinal motility recovery.更多还原