扩张器包膜内预制尿道的初步研究

PRELIMINARY STUDY ON PREFABRICATED URETHRA IN EXPANDER CAPSULE

目的探讨明胶海绵-微粒黏膜移植于扩张器包膜上预制尿道的可行性。方法8周龄贵州小型香猪8只,雌雄不限,体重20～25kg,每只猪背部皮下埋置6个15mL扩张器,2周后取猪自体口腔黏膜,制备为直径<1mm的微粒黏膜。将涂抹不同扩增面积比例(4∶1、8∶1、16∶1)自体微粒黏膜的3cm×2cm大小明胶海绵置于扩张器包膜上,使黏膜面与包膜接触,作为A、B、C组(n=2);植入单纯明胶海绵作为空白对照组(D组,n=2)。术后立即注水使扩张器内压强为40mmHg(1mmHg=0.133kPa)。术后观察动物一般情况,1、2、3周后取材行大体观察、HE染色及免疫组织化学染色观察。结果术后各组动物均存活至实验完成,切口均愈合良好。大体观察:术后1周A、B、C组明胶均未明显降解,黏膜散在存活,未完全融合成片,3组黏膜愈合率比较差异均有统计学意义(P<0.05),A、B组优于C组,A组优于B组;2周A、B、C组明胶海绵部分吸收,黏膜大部分成活,A、B组黏膜愈合率优于C组(P<0.05);3周A、B、C组明胶海绵仍未完全吸收,创面基本黏膜化,3组间黏膜愈合率比较差异无统计学意义(P>0.05)。D组各时间点均未见新生黏膜。组织学及免疫组织化学染色观察:A、B、C组各时间点均可见黏膜上皮成活及炎性细胞浸润,均可见抗广谱角蛋白阳性细胞,3周时各组黏膜上皮呈极性排列,黏膜下新生血管丰富;D组均未见黏膜细胞及阳性染色细胞。术后1周A、B、C组间阳性染色面积百分比比较差异均有统计学意义(P<0.05),A、B组大于C组,A组大于B组;2、3周A、B组阳性染色面积百分比明显大于C组(P<0.05),A、B组间差异无统计学意义(P>0.05)。结论微粒黏膜-明胶海绵复合移植于扩张器包膜上可形成黏膜衬里,2周可完全上皮化,有利于维持预制尿道的正常功能。

Objective To investigate the feasibility of prefabricating urethra in the expander capsule with gelatin sponge and micro-mucosa compound transplantation. Methods Eight 8-week-old Guizhou miniature pigs （male and/or female） weighing 20-25 kg were used. Six expanders （15 mL） were placed subcutaneously on the dorsal thorax of each miniature pig. Autologous oral mucosa of every pig was harvested 2 weeks later to prepare micro-mucosa with a diameter less than 1 mm. Gelatin sponge 3 cm × 2 cm in size was transplanted to the expander capsule after being coated by the autologous micro-mucosa at the area expansion ratio of 4 ∶ 1 （group A）,8 ∶ 1 （group B）,and 16 ∶ 1 （group C）,respectively （n=2 per group）. The implantation of gelatin sponge served as the blank control （group D,n=2）. Physiological saline was injected into the expander immediately after operation,and the pressure in the expander was 40 mm Hg （1 mm Hg=0.133 kPa）. The postoperative general condition of the animals was observed. At 1,2,and 3 weeks after operation,the animals were killed to receive general,HE staining,and immunohistochemistry staining observations. Results All animals survived till the end of the experiment. The wounds healed well. General observation：in groups A,B,and C at 1 week after operation,there was no obvious degeneration of gelatin,the mucous was survived partially,and there were signifi cant differences among three groups in terms of mucosa healing rate （P 〈 0.05）,groups A and B were better than group C,and group A was better than group B; at 2 weeks,the gelatin sponge was partly absorbed,most of the mucosa survived,and the mucosa healing rate of groups A and B was better than that of group C （P 〈 0.05）; at 3 weeks,the gelatin sponge was still not absorbed completely,the wound reached epithelialization approximately,and there were no significant differences among three groups in terms of mucosa healing rate （P 〉 0.05）. No neo-mucosa was evident in group D at each time point. Histology and immunohistochemistry staining observation：at each time point,the mucosa epithelium survival,inflammatory cell infiltration,and pan-cytokeratin were evident in groups A,B,and C; at 3 weeks after operation,the stratified squamous epithelium presented obvious polarity and the submucous neovascularization was abundant in groups A,B,and C. There was no mucosa epithelium and positive stained pan-cytokeratin in group D. For the percentage ofpositive pan-cytokeratin stained area,there were signif icant differences among groups A,B,and C 1 week after operation （P 〈 0.05）; at 2 and 3 weeks after operation,there was signif icant difference between group A and group C,and between group B and group C （P 〈 0.05）; but no signifi cant difference was evident between group A and group B （P 〉 0.05）. Conclusion Micro-mucosa and gelatin spongy compound transplantation on the expander capsule can form mucosal lining,achieve complete epithelialization in 2 weeks,and contribute to maintain the normal function of prefabricatied urethra.