Snedeker J G, Pelled G, Zilberman Y, Ben Arav A, Huber E, Müller R, Gazit D
Department of Orthopedics, University of Zurich, Balgrist, Switzerland.
Cells Tissues Organs. 2009;190(2):111-9. doi: 10.1159/000189211. Epub 2008 Dec 22.
Fibered confocal laser scanning microscopes have given us the ability to image fluorescently labeled biological structures in vivo and at exceptionally high spatial resolutions. By coupling this powerful imaging modality with classic optical elastography methods, we have developed novel techniques that allow us to assess functional mechanical integrity of soft biological tissues by measuring the movements of cells in response to externally applied mechanical loads. Using these methods we can identify minute structural defects, monitor the progression of certain skeletal tissue disease states, and track subsequent healing following therapeutic intervention in the living animal. Development of these methods using a murine Achilles tendon model has revealed that the hierarchical and composite anatomical structure of the tendon presents various technical challenges that can confound a mechanical analysis of local material properties. Specifically, interfascicle gliding can yield complex cellular motions that must be interpreted within the context of an appropriate anatomical model. In this study, we explore the various classes of cellular images that may result from fibered confocal microscopy of the murine Achilles tendon, and introduce a simple two-fascicle model to interpret the images in terms of mechanical strains within the fascicles, as well as the relative gliding between fascicles.
光纤共聚焦激光扫描显微镜使我们能够在体内以极高的空间分辨率对荧光标记的生物结构进行成像。通过将这种强大的成像方式与经典的光学弹性成像方法相结合，我们开发了新的技术，通过测量细胞响应外部施加的机械负荷的运动，来评估软生物组织的功能机械完整性。使用这些方法，我们可以识别微小的结构缺陷，监测某些骨骼组织疾病状态的进展，并跟踪活体动物治疗干预后的后续愈合情况。利用小鼠跟腱模型开发这些方法的过程中发现，肌腱的分层和复合解剖结构带来了各种技术挑战，可能会混淆对局部材料特性的力学分析。具体而言，束间滑动会产生复杂的细胞运动，必须在适当的解剖模型背景下进行解释。在本研究中，我们探索了小鼠跟腱光纤共聚焦显微镜检查可能产生的各类细胞图像，并引入了一个简单的双束模型，以便根据束内的机械应变以及束间的相对滑动来解释这些图像。
