Pope J C, Davis M M, Smith E R, Walsh M J, Ellison P K, Rink R C, Kropp B P
Division of Pediatric Urology, James Whitcomb Riley Hospital for Children, Indiana University Medical Center, Indianapolis, USA.
J Urol. 1997 Sep;158(3 Pt 2):1105-10. doi: 10.1097/00005392-199709000-00106.
Small intestinal submucosa has previously been shown to promote regeneration of transitional epithelium, smooth muscle and peripheral nerves in rat and dog bladders. The origin of these regenerated components is presently unknown. This study attempts to define the origin of vascular, smooth muscle and peripheral nerve regeneration.
A total of 22 adult male dogs weighing 25 to 30 kg. underwent partial cystectomy and immediate augmentation with a small intestinal submucosa patch graft. The small intestinal submucosa graft-native bladder interface was marked with permanent marking sutures for future reference. Small intestinal submucosa regenerated bladders were harvested at 2, 3, 4, 6, 8 and 10 weeks after augmentation. The tissue was then studied with routine histology and immunohistochemistry using factor VIII, smooth muscle specific actin (1A4) and neurofilament staining.
Results demonstrated that epithelialization of the graft surface was complete by 3 to 4 weeks with normal transitional histology. In the early periods neovascularization was prominent throughout the entire graft, as shown by factor VIII staining. Later more mature vessels were noted. Early in muscle formation sheets of elongated spindle cells extended into the graft from the incised native bladder at both surgical margins and ran parallel to the mucosal surface. At 4 weeks this spindle cell proliferation completely traversed the graft. Trichrome stained sections of the 4-week-old grafts showed no evidence of muscle differentiation and the spindle cells appeared to be fibroblasts. However, these cells stained positive for smooth muscle specific actin (1A4), indicating myogenic potential. Between weeks 4 and 6 the spindle cells became more haphazardly arranged and were separated by loose interstitium. By weeks 8 to 10 there was distinct smooth muscle bundle formation within these areas of proliferating myocytes. Neural regeneration appeared to coincide with smooth muscle development. Early neurofilament positive cells were noted predominantly at the graft-native bladder interface. At 4 weeks neurofilament positive cells were present throughout the graft and by 10 weeks nerve trunks composed of several nerve fibers were identified in association with newly formed smooth muscle bundles.
Small intestinal submucosa serves as a platform for bladder regeneration. Neovascularization smooth muscle and neural regeneration appear to occur through pannus ingrowth from the graft-native bladder interface. Smooth muscle regeneration seems to begin with the maturation of myofibroblasts, which migrate into the graft as early as 2 weeks after augmentation, and it progresses to the formation of distinct smooth muscle bundles by 10 weeks.
先前已证明小肠黏膜下层可促进大鼠和犬膀胱移行上皮、平滑肌和周围神经的再生。目前尚不清楚这些再生成分的来源。本研究试图确定血管、平滑肌和周围神经再生的来源。
选取22只体重25至30千克的成年雄性犬，行部分膀胱切除术，并用小肠黏膜下层补片立即进行膀胱扩大术。小肠黏膜下层移植物与天然膀胱的界面用永久性标记缝线标记，以备将来参考。在扩大术后2、3、4、6、8和10周时获取小肠黏膜下层再生膀胱。然后使用因子VIII、平滑肌特异性肌动蛋白（1A4）和神经丝染色，通过常规组织学和免疫组织化学对组织进行研究。
结果表明，3至4周时移植物表面上皮化完成，组织学表现为正常移行上皮。早期，因子VIII染色显示整个移植物内新生血管形成明显。后来观察到更成熟的血管。在肌肉形成早期，细长梭形细胞片从手术边缘切开的天然膀胱延伸至移植物内，并与黏膜表面平行排列。4周时，这种梭形细胞增殖完全穿过移植物。4周龄移植物的三色染色切片未显示肌肉分化迹象，梭形细胞似乎是成纤维细胞。然而，这些细胞平滑肌特异性肌动蛋白（1A4）染色呈阳性，表明具有肌源性潜能。在4至6周期间，梭形细胞排列变得更加杂乱无章，并被疏松的间质分隔。到8至10周时，在这些增殖的肌细胞区域内有明显的平滑肌束形成。神经再生似乎与平滑肌发育同步。早期神经丝阳性细胞主要见于移植物与天然膀胱的界面。4周时，整个移植物内均有神经丝阳性细胞，到10周时，在新形成的平滑肌束附近可识别出由数条神经纤维组成的神经干。
小肠黏膜下层可作为膀胱再生的平台。新生血管形成、平滑肌和神经再生似乎是通过从移植物与天然膀胱界面向内生长的血管翳发生的。平滑肌再生似乎始于肌成纤维细胞的成熟，这些细胞在扩大术后最早2周就迁移至移植物内，并在10周时发展为明显的平滑肌束。
