因關節軟骨在受損後因組織再生能力不理想，在缺少有效的治療手段下將轉變成骨關節炎，而骨關節炎經常發生在全球尤其是高齡者身上造成患者的行動不便。近年來，軟骨的組織工程概念被廣泛使用，由細胞、支架和信號三個要素組合而成，期待能提升新生組織與宿主組織的整合與修復效果。
去細胞材料能在保留細胞外基質結構與成分的同時去除會引起免疫反應的細胞成分。軟骨組織由於結構緊密需要以粉末或者層片的形式才能有效地去除細胞成分，不過會喪失作為三維支架的能力。因此，本研究將水凝膠與去細胞軟骨層片交互疊合後形成複合三維支架，並在此基礎上添加髕骨下脂肪墊間質幹細胞以符合完整的組織工程框架。去細胞軟骨層片中所包含的大量細胞外基質能提供細胞分化與生長的原生生化信號與生存結構，同時改善水凝膠所欠缺的機械性質強度。
此複合支架在經過SEM所拍攝的微觀結構中可發現水凝膠與層片相互鍵結，擁有完整且穩定的支架結構，因此在壓縮的機械強度上也能得到明顯提升，且在層數提升時應能有更好的表現。在使用脂肪墊間質幹細胞所進行的體外活性測試中證明材料的無毒性後將複合支架與細胞結合應用至全層軟骨缺損的兔子動物模型當中。從術後4週與12週對新生組織時進行的巨觀觀察能發現表面的修復情況在植入支架後能夠得到明顯的提升，在幹細胞的輔助下能出現與宿主組織幾乎相同的色澤與光滑的表面。從微電腦斷層掃描 (micro-CT) 評估的骨密度中，支架的加入能在12週後顯著的拉高骨密度達到健康的程度。骨小樑的厚度則是所有組別都能在新生初期就有正常的數值表現。但在通過組織染色時發現，複合支架中的去細胞軟骨層片不易降解，導致治療初期時新生組織與周圍宿主組織整合效率降低，單純植入複合支架在12週時雖然表層軟骨有不錯的修復情形，但軟骨下骨的區域依舊會有支架的殘留。然而，擁有幹細胞輔助的組別能於12周後順利分解支架材料並完成軟骨下骨的組織整合。根據以上結果，本研究所設計的多層複合支架在結合幹細胞後具有良好的軟骨修復能力以及軟骨下骨再生效果。

Due to the unsatisfactory tissue regeneration ability after articular cartilage is damaged, it will turn into osteoarthritis in the absence of effective treatment methods. Osteoarthritis often occurs all over the world, especially among the elderly, resulting in inconvenience for patients. In recent years, the concept of tissue engineering of cartilage has been widely used. It is composed of three elements: cells, scaffolds, and signals, and it is expected to improve the integration and repair effect of new tissue and host tissue.
Decellularized materials can remove cellular components that can cause an immune response while retaining the structure and components of the extracellular matrix. Due to the compact structure, cartilage tissue needs to be in the form of powder or layer to effectively remove cell components, but it will lose the ability to serve as a three-dimensional scaffold. Therefore, in this study, the hydrogel and decellularized cartilage sheets were laminated alternately to form a composite three-dimensional scaffold, and on this basis, the infrapatellar fat pad mesenchymal stem cells were added to conform to the complete tissue engineering framework. The abundant extracellular matrix contained in decellularized cartilage sheets can provide native biochemical signals and survival structures for cell differentiation and growth while improving the strength of mechanical properties that hydrogels lack.
In the microstructure of this composite scaffold taken by SEM, it can be found that the hydrogel and the layers are bonded to each other, and has a complete and stable scaffold structure, so the compressive modulus can also be significantly improved, and the number of layers is increased. should perform better. After the non-toxicity of the material was proved in the in vitro activity test using fat pad mesenchymal stem cells, the composite scaffold was combined with cells and applied to a rabbit animal model of full-thickness cartilage defect. From the macroscopic observation of the new tissue at 4 weeks and 12 weeks after the operation, it can be found that the repair of the surface can be significantly improved after implantation of the scaffold. With the help of stem cells, they can appear almost the same color and smooth as the host tissue surface. From the bone density assessed by micro-computed tomography (micro-CT), the addition of scaffolds can significantly increase bone density to a healthy level after 12 weeks. The thickness of trabecular bone was normal in all groups in the early regeneration. However, it was found through tissue staining that the decellularized cartilage layer in the composite scaffold was not easy to degrade, which leaded to a decrease in the integration efficiency of the new tissue and the surrounding host tissue at the initial stage of treatment. Although the superficial cartilage could be repaired well at 12 weeks after simply implanting the composite scaffold situation, the subchondral bone area still has scaffolding residues. However, the group with stem cell assistance was able to successfully decompose the scaffold material and complete the tissue integration of subchondral bone after 12 weeks. According to the above results, the multilayer composite scaffold designed in this study has good cartilage repair ability and subchondral bone regeneration effect after combining stem cells.

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