物理性刺激对骨膜软骨生成的影响

Effect of physical stimulus on periosteal chondroplasia

目的探讨物理性刺激对骨膜软骨生成方面的影响,以期培养出一种与正常关节软骨更相似的软骨组织。方法从新西兰大白兔胫骨近端内侧取下骨膜,将骨膜固定在支架上,然后将细胞支架悬吊在旋转瓶内,用水流产生的剪切应力去刺激骨膜。通过宏观观察、体积大小测量、组织切片染色与细胞外基质(ECM)成分的比较及生物力学测试分析软骨体外生长的最佳环境。结果宏观观察发现软骨生长的方向与水流的方向相同。组织切片染色可见有两层不同形态的软骨细胞和不同密度的ECM,免疫组织化学染色见在剪切应力的刺激下,软骨表面可分泌浅层蛋白质及润滑剂,且在不同大小的剪切应力刺激时,软骨表面还会产生不同厚度的表层。结论剪切应力刺激能使骨膜上的干细胞分化形成软骨,同时证明力学环境不仅影响细胞的分化与生长,而且影响细胞的形态与ECM的分泌。

Objective To study the impact of physical stimulus on periosteal chondroplasia with an intention of reconstructing cartilage tissue that has a biomechanical function and can be created either entirely in vivo or in vitro and subsequently implanted into the patient. Methods A series of biomechanical test methods were designed in order to investigate the mechanical properties of engineered cartilage under a variety of mechanical stress stimulations. The periosteal explants were harvested from proximal medial tibias of New Zealand rabbits and secured onto poly-ε-caprolactone （PCL） scaffolds. The composites （periosteum/PCL） were suspended in the spinner flask bioreactor and the spinner flask was located on the stirring machine. The stem ceils were stimulated by fluid shear stress under magnetic bar stirring. Results In gross observation, the thickness and length of neo-cartilage with shear force stimulation were significantly greater than those without shear force. The direction of elongation was parallel with fluid flow direction, regardless of composite orientation. Secondary, two different zones based on various cell morphology and distribution were clearly observed. The thickness of the superficial zone was greater in samples exposed to high shear force compared with low shear force. The superficial zone protein and lubricant were found in the engineered cartilage under shear stress stimulation. Conclusion The results reveal that shear stress can not only influence proliferation and differentiation of stem ceils, but also change chondrocyte morphology and increase extracellular matrix production.