Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, Korea.
BioMedical Research Institute, Kyungpook National University Hospital, Daegu, Korea.
J Korean Med Sci. 2020 Oct 26;35(41):e374. doi: 10.3346/jkms.2020.35.e374.
Tissue engineering can be used for bladder augmentation. However, conventional scaffolds result in fibrosis and graft shrinkage. This study applied an alternative polycaprolactone (PCL)-based scaffold (diameter = 5 mm) with a noble gradient structure and growth factors (GFs) (epidermal growth factor, vascular endothelial growth factor, and basic fibroblast growth factor) to enhance bladder tissue regeneration in a rat model.
Partially excised urinary bladders of 5-week-old male Slc:SD rats were reconstructed with the scaffold (scaffold group) or the scaffold combined with GFs (GF group) and compared with sham-operated (control group) and untreated rats (partial cystectomy group). Evaluations of bladder volume, histology, immunohistochemistry (IHC), and molecular markers were performed at 4, 8, and 12 weeks after operation.
The bladder volumes of the scaffold and GF group recovered to the normal range, and those of the GF group showed more enhanced augmentation. Histological evaluations revealed that the GF group showed more organized urothelial lining, dense extracellular matrix, frequent angiogenesis, and enhanced smooth muscle bundle regeneration than the scaffold group. IHC for α-smooth muscle actin, pan-cytokeratin, α-bungarotoxin, and CD8 revealed that the GF group showed high formation of smooth muscle, blood vessel, urothelium, neuromuscular junction and low immunogenicity. Concordantly, real-time polymerase chain reaction experiments revealed that the GF group showed a higher expression of transcripts associated with smooth muscle and urothelial differentiation. In a 6-month in vivo safety analysis, the GF group showed normal histology.
This study showed that a PCL scaffold with a gradient structure incorporating GFs improved bladder regeneration functionally and histologically.
组织工程可用于膀胱扩大术。然而，传统支架会导致纤维化和移植物收缩。本研究应用一种替代的聚己内酯（PCL）为基础的支架（直径= 5 毫米），具有高贵的梯度结构和生长因子（EGF、VEGF 和 bFGF），以增强在大鼠模型中的膀胱组织再生。
部分切除 5 周龄雄性 Slc：SD 大鼠的泌尿道膀胱，用支架（支架组）或支架联合生长因子（GF 组）进行重建，并与假手术（对照组）和未处理的大鼠（部分膀胱切除术组）进行比较。术后 4、8 和 12 周进行膀胱容量、组织学、免疫组织化学（IHC）和分子标志物评估。
支架和 GF 组的膀胱容量恢复到正常范围，GF 组的膀胱容量恢复更为显著。组织学评价显示，GF 组的尿路上皮衬里更有组织，细胞外基质更密集，血管生成更频繁，平滑肌束再生增强。α-平滑肌肌动蛋白、pan-cytokeratin、α-银环蛇毒素和 CD8 的 IHC 显示，GF 组的平滑肌、血管、尿路上皮、神经肌肉接头形成较高，免疫原性较低。实时聚合酶链反应实验表明，GF 组的平滑肌和尿路上皮分化相关转录物的表达较高。在 6 个月的体内安全性分析中，GF 组显示出正常的组织学。
本研究表明，一种含有生长因子的梯度结构 PCL 支架在功能和组织学上改善了膀胱再生。
