Fukumoto T, Sperling J W, Sanyal A, Fitzsimmons J S, Reinholz G G, Conover C A, O'Driscoll S W
Cartilage and Connective Tissue Research Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Osteoarthritis Cartilage. 2003 Jan;11(1):55-64. doi: 10.1053/joca.2002.0869.
Periosteum contains undifferentiated mesenchymal stem cells that have both chondrogenic and osteogenic potential, and has been used to repair articular cartilage defects. During this process, the role of growth factors that stimulate the periosteal mesenchymal cells toward chondrogenesis to regenerate articular cartilage and maintain its phenotype is not yet fully understood. In this study, we examined the effects of insulin-like growth factor-1 (IGF-1) and transforming growth factor-beta1 (TGF-beta1), alone and in combination, on periosteal chondrogenesis using an in vitro organ culture model.
Periosteal explants from the medial proximal tibia of 2-month-old rabbits were cultured in agarose under serum free conditions for up to 6 weeks. After culture the explants were weighed, assayed for cartilage production via Safranin O staining and histomorphometry, assessed for proliferation via proliferative cell nuclear antigen (PCNA) immunostaining, and assessed for type II collagen mRNA expression via in situ hybridization.
IGF-1 significantly increased chondrogenesis in a dose-dependent manner when administered continuously throughout the culture period. Continuous IGF-1, in combination with TGF-beta1 for the first 2 days, further enhanced overall total cartilage growth. Immunohistochemistry for PCNA revealed that combining IGF-1 with TGF-beta1 gave the strongest proliferative stimulus early during chondrogenesis. In situ hybridization for type II collagen showed that continuous IGF-1 maintained type II collagen mRNA expression throughout the cambium layer from 2 to 6 weeks.
The results of this study demonstrate that IGF-1 and TGF-beta1 can act in combination to regulate proliferation and differentiation of periosteal mesenchymal cells during chondrogenesis.
骨膜含有具有软骨生成和成骨潜能的未分化间充质干细胞，已被用于修复关节软骨缺损。在此过程中，刺激骨膜间充质细胞向软骨生成方向分化以再生关节软骨并维持其表型的生长因子的作用尚未完全明确。在本研究中，我们使用体外器官培养模型研究了胰岛素样生长因子-1（IGF-1）和转化生长因子-β1（TGF-β1）单独及联合应用对骨膜软骨生成的影响。
取2月龄兔胫骨近端内侧的骨膜外植体，在无血清条件下于琼脂糖中培养长达6周。培养后称取外植体重量，通过番红O染色和组织形态计量学检测软骨生成情况，通过增殖细胞核抗原（PCNA）免疫染色评估增殖情况，通过原位杂交评估II型胶原mRNA表达。
在整个培养期间持续给予IGF-1时，其以剂量依赖性方式显著增加软骨生成。在培养的前两天将持续给予的IGF-1与TGF-β1联合应用，进一步增强了总体软骨生长。PCNA免疫组织化学显示，在软骨生成早期，将IGF-1与TGF-β1联合应用可产生最强的增殖刺激。II型胶原原位杂交显示，持续给予IGF-1可在2至6周内维持整个生发层的II型胶原mRNA表达。
本研究结果表明，IGF-1和TGF-β1可联合作用，在软骨生成过程中调节骨膜间充质细胞的增殖和分化。
