Laboratory of Biomechanical Orthopedics, EPFL, CH-1015 Lausanne, Switzerland.
Eur Cell Mater. 2010 Feb 22;19:41-9. doi: 10.22203/ecm.v019a05.
In clinical situations, bone defects are often located at load bearing sites. Tissue engineering scaffolds are future bone substitutes and hence they will be subjected to mechanical stimulation. The goal of this study was to test if cyclic loading can be used as stimulatory signal for bone formation in a bone scaffold. Poly(L-lactic acid) (PLA)/ 5% beta-tricalcium phosphate (beta-TCP) scaffolds were implanted in both distal femoral epiphyses of eight rats. Right knees were stimulated (10N, 4Hz, 5 min) five times, every two days, starting from the third day after surgery while left knees served as control. Finite element study of the in vivo model showed that the strain applied to the scaffold is similar to physiological strains. Using micro-computed tomography (CT), all knees were scanned five times after the surgery and the related bone parameters of the newly formed bone were quantified. Statistical modeling was used to estimate the evolution of these parameters as a function of time and loading. The results showed that mechanical stimulation had two effects on bone volume (BV): an initial decrease in BV at week 2, and a long-term increase in the rate of bone formation by 28%. At week 13, the BV was then significantly higher in the loaded scaffolds.
在临床情况下，骨缺损通常位于承重部位。组织工程支架是未来的骨替代物，因此它们将受到机械刺激。本研究的目的是测试循环加载是否可作为骨支架中骨形成的刺激信号。将聚（L-乳酸）（PLA）/5%β-磷酸三钙（β-TCP）支架植入 8 只大鼠的远端股骨骨骺中。从术后第 3 天开始，右膝每隔两天接受 5 次 10N、4Hz、5 分钟的刺激，而左膝作为对照。体内模型的有限元研究表明，施加在支架上的应变与生理应变相似。使用微计算机断层扫描（CT），在手术后对所有膝关节进行了 5 次扫描，并对新形成的骨的相关骨参数进行了定量分析。统计模型用于估计这些参数随时间和加载的演变。结果表明，机械刺激对骨体积（BV）有两种影响：第 2 周 BV 初始减少，以及骨形成率长期增加 28%。第 13 周时，负载支架中的 BV 明显更高。
