以組織工程製備新生軟骨作為軟骨修復

1. 以組織工程製備新生軟骨作為軟骨修復 隨著人類平均壽命的延長，關節病變成為年長者最常罹患的退化性疾病。六十五歲以上的老年族群中，約有四分之三患有程度不等的關節炎。使得關節炎的研究及其診斷與治療成為本世紀最被重視的課題之一。關節炎，不論是骨性關節炎、類風濕性關節炎以及外傷性關節炎，共同的病理表徵是關節軟骨細胞外間質的破壞。現今治療骨關節炎的方式有兩種，一為保守式的藥物治療主要用於抑制疼痛及發炎反應；另一種則是使用外科手術的方式，包括清創、刮磨、鑽引、骨創、截骨矯正、自體骨軟骨移植、自體軟骨細胞移植及最終的人工關節置換等。各種的治療方式，均有其條件或限制，長期的療效並不理想。近年來再生醫學的快速進展，利用組織工程的技術，在體外培養新生組織再移植入體內，進而促使組織、器官再生，已成為治療關節病變的另一種方式。本研究的目的是將軟骨細胞培養在第一型膠原蛋白骨架中，以建構一種可作為移植之用的新生軟骨組織。並分析探討此軟骨組織的細胞型態、分布及其細胞外間質的基因及蛋白表現。將人類軟骨細胞自軟骨組織中分離出來之後，藉由不同種生長激素的刺激來觀察細胞的變化；加入IGF-I及TGF-beta 1可促進軟骨細胞表現軟骨相關蛋白， FGF-2可促進軟骨細胞之增生。另以組織切片染色及分子生物學等工具來確定體外培養的新生軟骨組織之特性。在體外培養二週的軟骨組織切片觀察，發現人類軟骨細胞可在老鼠尾巴所萃取來的第一型膠原蛋白中分化，在第四週時也可以觀察到軟骨的特殊型態lacunae。這一種新型態的三度空間培養模式除了可提供軟骨組織臨床移植之用，也可作為研究軟骨再生的體外模型，希望這種體外培養模式的建立可為將來的關節炎治療帶來新的思維及契機。

2. Cartilage Repair and Regeneration by Tissue-Engineered Neocartilage • Tissue engineering of cartilage is a novel medical therapy for arthritis. Arthritis is the most common joint disease and causes extremity deformity. Approximately three-fourth of people aged over 65 years has radiographic evidence of osteoarthritis involving at least one joint. Both osteoarthritis and rheumatoid arthritis, commonly featured degradation of articular cartilage. In fact, large cartilage defects (>4 mm diameter 2-3mm thick) due to trauma as well as arthritis do not normally heal spontaneously. In severe cases, surgical removal of the damaged and dysfunctional joint and installation of an artificial joint prosthesis are indicated.Therapeutic strategies focused on arthrits or trauma have been established, including anti-inflammatory drugs and surgical treatments. Several surgical approaches have been proposed, including cell transplantation, mosaicplasty, periosteal implantation, biomaterial implantation, growth factor treatment, hole-drilling through subchondral bone, and tissue engineering. There is only one cell type, the chondrocyte, in cartilage; therefore in vitro cartilage tissue engineering becomes feasible and one of the strategies in cartilage defect. Despite cartilage tissue engineering has been reported by using primary chondrocytes; however, difficulties in maintaining phenotype and genotype during monolayer culture and deficiency of chondrocytes source still remain unsolved problems for in vitro cartilage tissue engineering. Collagen matrix anchored by chondrocytes was reported to produce a cartilage-like artificial tissue in our laboratory and other’s.This research focused on the manufacture and characterization of an in vitro cartilaginous tissue. By using type I collagens and human chondrocytes as a chondrocyte- matrix construct in three dimensional culture conditions, a tissue-engineered cartilage was made to be a replacement implant for large defect of cartilage. Histological evaluation of the neocartilage exhibited chondroid phenotype as early as day 14. A pale stained and hyaline-like extracellular matrix was observed on day 28. On alcian blue staining sections, some lacuna-like structures were well recognized. These features indicated that the chondrogenic maturation occurred in the 3D-cultured chohdrocyte- collage constructs. The effects of different growth factors on human chondrocytes were also determined. IGF-I and TGF-beta 1 could promote expression of ECM. FGF-2 could stimulate proliferation of the cells. Clinical observation revealed that severe cartilage damage could not heal spontaneously. This research might provide a model for studying cartilage repair/regeneration and tissue-engineered cartilage implantation. The4tissue-engineered cartilage might provide a novel technology for repair of large cartilage defects in clinic. Cartilage Repair and Regeneration by Tissue-Engineered Neocartilage