Sievert K D, Bakircioglu M E, Nunes L, Tu R, Dahiya R, Tanagho E A
Department of Urology, University of California School of Medicine, San Francisco, California, USA.
J Urol. 2000 Jun;163(6):1958-65.
To evaluate urethral replacement by a free homologous graft of acellular urethral matrix in a rabbit model.
In 30 male New Zealand rabbits, a 0.8 to 1.1 cm. segment of the urethra was resected, replaced with an acellular matrix graft of 1.0 to 1.5 cm. (mean 1.3 cm.), and placed on an 8F feeding tube. Additionally 4 animals underwent sham operation. At varying intervals before sacrifice (from 10 days to 8 months), the animals underwent urodynamic evaluation and retrograde urethrography (for which 4 untreated rabbits served as control). The grafted specimens were prepared for evaluation histologically and by reverse-transcription polymerase chain reaction (RT-PCR).
In all animals, the acellular matrix graft remained in its original position. Histological examination showed complete epithelialization and progressive vessel infiltration. At 3 months, smooth muscle bundles were first observed infiltrating the matrix at the end-to-end anastomosis; after 6 months, the smooth muscle bundles had grown into one-third of the matrix. Urodynamics did not detect any difference between the control and matrix-grafted animals in bladder volume, leak-point pressure and residual volume. RT-PCR detected an increase in IGF mRNA in the graft between week 3 and month 6 and in HB-EGF mRNA after day 10 through month 3. TGF-alpha mRNA was not detected; TGF-beta mRNA was unchanged from normal urethral tissue. By 8 months, the host and implant could not be differentiated by urethrography.
The acellular urethral matrix allows single-stage urethral reconstruction. All tissue components were seen in the grafted matrix after 3 months, with further improvement over time; however, the smooth muscle in the matrix was less than in normal rabbit urethra and was not well oriented. RT-PCR revealed the importance of time-dependent growth factor influences during regeneration.
在兔模型中评估脱细胞尿道基质的游离同种异体移植物对尿道的替代作用。
选取30只雄性新西兰兔，切除0.8至1.1厘米长的尿道段，用1.0至1.5厘米（平均1.3厘米）的脱细胞基质移植物替代，并置于8F饲管上。另外4只动物接受假手术。在处死前的不同时间间隔（从10天到8个月），对动物进行尿动力学评估和逆行尿道造影（4只未处理的兔子作为对照）。将移植标本制备用于组织学评估和逆转录聚合酶链反应（RT-PCR）。
在所有动物中，脱细胞基质移植物均保留在原位。组织学检查显示完全上皮化和逐渐的血管浸润。3个月时，首次观察到平滑肌束在端端吻合处浸润基质；6个月后，平滑肌束已生长到基质的三分之一。尿动力学未检测到对照动物和基质移植动物在膀胱容量、漏点压力和残余尿量方面有任何差异。RT-PCR检测到移植组织中第3周和第6个月时IGF mRNA增加，第10天至第3个月时HB-EGF mRNA增加。未检测到TGF-α mRNA；TGF-β mRNA与正常尿道组织相比无变化。到8个月时，尿道造影无法区分宿主和植入物。
脱细胞尿道基质可实现单阶段尿道重建。3个月后在移植基质中可见所有组织成分，且随时间推移进一步改善；然而，基质中的平滑肌少于正常兔尿道，且排列不佳。RT-PCR揭示了再生过程中时间依赖性生长因子影响的重要性。
