【作者】 张磊；

【导师】 宋国栋；

【作者基本信息】 山东大学 ， 外科学， 2007， 硕士

【摘要】 目的严重烧伤、创伤、休克、感染等多种病理因素，均可导致肠粘膜屏障功能障碍。肠源性感染不但与早期暴发性脓毒症、持续的高代谢反应和脓毒性休克的发生、发展密切相关，而且在多器官功能障碍综合征(MODS)的发病机理中起关键作用。进一步探索防治肠源性感染的有效措施，特别是在严重创伤应激后如何维护或尽快恢复肠道的正常屏障是急需研究的重要课题。生长激素(GH)除具有促进蛋白质合成、加快创伤愈合、改善免疫功能、降低应激反应等作用外，还能够促进肠粘膜细胞增殖、抑制细胞凋亡、维护肠粘膜屏障功能。本研究采用能够引起肠源性感染的烧伤后免疫抑制大鼠模型，探讨重组人生长激素(rhGH)早期大剂量应用对大鼠肠粘膜通透性、肠道细菌内毒素移位及肠粘膜超微结构的影响。在此基础上应用于临床，观察rhGH对严重烧伤病人肠粘膜屏障功能的保护作用。方法选用成年雄性Wistar大鼠30只，随机分为对照组6只、烧伤组和GH组各12只。后两组造成25％总体表面积(TBSA)Ⅲ度烧伤创面，从伤后2h开始分别皮下注射等渗盐水和rhGH(1.33IU／kg／d)。于伤后24、96h，观察血浆二胺氧化酶活性、D-乳酸与内毒素含量；同时利用病理组织学、透射电镜等方法观察末端回肠粘膜组织形态、肠粘膜上皮细胞及细胞连接(Cell junction)超微结构。在总结、分析实验结果的基础上，结合已有的临床经验，选择40例严重烧伤病人，随机分为实验组和对照组各20例。实验组于伤后48h开始每日皮下注射rhGH 0.3IU／kg／d，连用7d，对照组给予安慰剂。实验前后分别测定血浆二胺氧化酶活性、内毒素含量及尿乳果糖／甘露醇(L／M)比值，同时观察血尿常规及肝肾功能等变化。结果1．伤后24、96h烧伤组大鼠血浆二胺氧化酶活性、D-乳酸和内毒素含量均高于对照组和GH组(P＜0.01～0.05)。伤后24h GH组也高于对照组(P＜0.01～0.05)，至伤后96h均有不同程度下降。伤后96h内毒素含量与对照组无明显差异(P＞0.05)。伤后24、96h，烧伤组肠粘膜形态结构、上皮细胞及细胞连接损伤严重，GH组明显减轻，基本接近对照组。2．实验组与对照组患者用药前后的一般情况及肝肾功能间的变化无显著性意义；实验组用药前后及用药后两组的二胺氧化酶活性、内毒素含量及肠粘膜通透性(L／M)相比较，其差异均有显著性意义(P＜0.01)。结论rhGH早期应用能够降低严重烧伤大鼠肠粘膜通透性，减轻肠道细菌内毒素移位，减轻脏器损伤，维护肠粘膜形态结构的基本正常。对严重烧伤病人，rhGH每日皮下注射rhGH 0.3IU／Kg／d，能够减轻肠粘膜损害，减轻肠道／细菌内毒素移位，保护肠粘膜屏障功能。更多还原

【Abstract】 ObjectiveSevere burn, trauma, shock, infection and other pathological factors can all lead to intestinal barrier dysfunction. It might be suggested that gut derived infection play an important role in the pathogenesis of early sepsis, hypermetabolism, septic shock and MODS. It is deeply in need and very impotant to explore effective methods to preserve normal intestinal mucosal barrier and prevent gut derived infection caused by traumatic stress. Besides accelerating wound healing, improving immune function, decreasing stress response, growth hormone(GH) can also promote postburn intestinal mucosal epithelial proliferation and inhibit injury epithelial apoptosis, thus preserve postburn intestinal mucosal barrier function.The current study was performed to explore the effects of great dose of recombinant human growth hormone(rhGH) presenting in early postburn stage in maintaining intestinal mucosal permeability, endotoxin translocation and intestinal mucosal ultrastructure. Subsequently, clinical trial based on the experiments on animals was performed to observe the protective effects on intestinal mucosal barrier function in severe burned patients. Methods30 grown male Wistar rats were randomly divided into three groups, control, scalding and GH groups.The rats in scalding and GH groups were inflicted with 25% TBSA III degree scalding on the back .The scalded rats were administered with normal saline and GH(1.33U/kg/d) since 2 postburn hours (PBHs), respectively in the last two group.The changes of blood level of diamine oxidase (DAO), D-lacticacid and endotoxin were observed on 24 and 96 PBHs. The changes of epithelial and cell junction ultrastructure, the intestinal mucosal pathomorphology of distal end of ileal mucosal tissue were also observed on 24 and 96 PBHs. According to the results of those experiments on animals, 40 severe burn patients were randomly divided into test(T) and control(C) groups with 20 patients in each group.Patients in T group were given rhGH 0.3IU/Kg/d for 7 days since 48 PBHs,while those in C group received placebo. Blood levels of DAO activity, endotoxin and urine lactulose/mannitol (L/M) test were monitored before and after the administration of the agents,while the change in blood and urine routine and hepatic and renal functional indices were also observed.Results1.The DAO acivity, D-lacticacid and endotoxin levels in plasma were evidently higher in scalding group than in control group and GH group (P<0.01～0.05) on 24 and 96 PBHs. The datas were also higher in GH group than in control group on 24 PBHs (P<0.01～0.05), and decreased on 96 PBHs. The endotoxin levels had no significant difference with contral group (P>0.05) on 96 PBHs. The intestinal mucosal morphology,epithelia and its cell junction in scalding group were severely injured but were significantly a meliorated by rhGH to near those in control group on 24 and 96 PBHs.2. There was no difference of the general data and the hepatic and renal functional indices between the two groups.The DAO activity, endotoxin levels and intestinal mucosal permeability (L/M) before administration were evidently higher than those after it (P<0.01) in T group,and the data in C group were evidently higher than those in T group (P<0.01) after administration.ConclusionsrhGH presented in early postburn stage can effectively lessen intestinal mucosal permeability, reduce the intestinal bacteria/endotoxin translocation .decrease the damage of organs and maintain the normal morphological structure of intestinal mucosa in severe burned rats. rhGH can also abate the degree of intestinal mucosal injury, reduce the intestinal bacteria/endotoxin translocation and protect intestinal mucosal barrier function in severe burned patients.更多还原