脱细胞羊膜修复兔尿道组织缺损的可行性

Feasibility of repairing urethral defects using human acellular amniotic membrane in rabbits

背景:脱细胞羊膜的抗原性低,组织相容性好,在眼科眼表疾病及大面积烧伤中有较多的研究和临床应用,但在泌尿系统中的组织缺损修复较少报道。目的:通过脱细胞羊膜修复兔尿道组织的缺损实验,探讨去细胞人羊膜是否能作为修复尿道组织缺损的一种有效安全的支架材料。设计、时间及单位:随机对照动物实验,实验于2007-04/06在广西医科大学动物实验中心完成。材料:新西兰兔32只由广西医科大学动物实验中心提供。新鲜人羊膜取自广西医科大学一附院产科。方法:脱细胞羊膜的制备:新鲜羊膜先使用1%甲醛-0.2%戊二醛交联保护,再使用0.125%胰酶-0.05mol/LEDTA消化,最后使用0.5%曲拉通洗涤。32只新西兰雄兔分为3组,实验组12只,对照组12只,假手术组8只。前2组制备尿道缺损模型,实验组以脱细胞羊膜修复兔尿道组织缺损,对照组直接吻合尿道,假手术组仅游离尿道组织,不行尿道手术。主要观察指标:术后10,21,42d行修复尿道病理组织学检查观察上皮细胞血管及平滑肌细胞生长情况,炎症细胞浸润情况。术后42d行尿道造影﹑尿动力学检查观察尿道压力变化及膀胱容量和称膀胱质量。结果:①制备好的脱细胞羊膜白色半透明,无细胞及碎片残留。②脱细胞羊膜修复兔尿道组织缺损实验组一病理切片检查:10d脱细胞羊膜周边已有尿道上皮细胞生长,未见急性排斥反应。21d脱细胞羊膜处尿道表面已被尿道上皮细胞覆盖,小血管生长,炎症细胞浸润减轻。42d实验组一少量平滑肌长入,血管生长良好,少量炎症细胞。3组尿动力学结果,尿道最高压,尿道最低压比较均无统计学意义(P>0.05)。称膀胱质量,假手术组和对照组膀胱质量差异有统计学意义(P<0.05)。结论:脱细胞羊膜修复兔的尿道组织缺损,上皮细胞和平滑肌细胞生长良好,未出现排斥反应和毒性表现,尿道通畅无狭窄,证实脱细胞羊膜是一种前景良好的尿道组织修复材料。

BACKGROUND：Acellular amniotic membrane used widely in treating ocular surface disease as well as extensive burn wounds due to its low antigenicity and excellent histocompatibility.However,it is poorly understood whether it can be used in repairing urethral defects.OBJECTIVE：To evaluate role and the feasibility of human acellular amniotic membrane （HAAM） in the rabbit urethral reconstruction.DESIGN,TIME AND SETTING：The randomized control experiment of animals was performed at the Laboratory Center of Guangxi Medical University between April and June 2007.MATERIALS：Thirty-two New Zealand rabbits were supplied by animal center of Guangxi Medical University.The human HAAM was obtained from Department of Obstetrics,First Affiliated Hospital of Guangxi Medical University.METHODS：HAAM was prepared by detergent-enzymatic approach.Firstly,the fresh amniotic membrane was protected with cross linking of 1% formaldehyde-0.2% glutaral,digested with 0.125% trypsogen-0.05 mol/L EDTA,followed by washing with 0.5% Triton X-100.Totally 32 New Zealand male rabbits were assigned into 3 groups：experimental group （n=12）,control group （n=12） and sham operation group （n=8）.Rabbits were prepared for urethral defects models in the experimental and control groups,which were repaired with HAAM or anastomosised directly.There was no urethral operation in the sham operation group.MAIN OUTCOME MEASURES：The growth of epithelial cells and smooth muscle cells,as well as inflammatory cell infiltration was observed by histopathologic examination at days 10,21 and 42 after operation.The urethral pressure changes and urinary bladder was examined by retrograde urethrography at day 42 after operation.RESULTS：①The prepared HAAM was translucent,there was no residual cells or fragments.②The pathological section examination showed that in the experimental group,some epithelial cells has grown without acute rejection at day 10 after operation,and several layers of urothelium covered HAAM at day 21 with reduced inflammatory cell infiltration.At day 42,a sprinkle of smooth muscle grew in HAAM with few inflammatory cells.Urodynamic studies indicated that there were no significant difference among 3 groups in the bladder volume,maximum urethral pressure and minimum urethral pressure （P 0.05）.The weight of bladder had obvious difference between the sham operation and control groups （P 0.05）.CONCLUSION：HAAM is an ideal biomaterial with well histocompatibility,biocompatibility and low antigenicity.HAAM is a good choice for urethral reconstruction.