James Hogg Research Centre-St Paul's Hospital, Vancouver, Canada.
BMC Musculoskelet Disord. 2011 Jan 26;12:26. doi: 10.1186/1471-2474-12-26.
Tenocytes have been implicated in the development of tendinosis, a chronic condition commonly seen in musculoskeletal overuse syndromes. However, the relation between abnormal tenocyte morphology and early changes in the fibrillar collagen matrix has not been closely examined in vivo. Second harmonic generation (SHG) microscopy is a recently developed technique which allows examination of fibrillar collagen structures with a high degree of specificity and resolution. The goal of this study was to examine the potential utility of SHG and multiphoton excitation fluorescence (MPEF) microscopy in understanding the relation between tenocytes and their surrounding collagenous matrix in early tendon overuse lesions.
Histological preparations of tendon were prepared from adult male Sprague-Dawley rats subjected to an Achilles tendon loading protocol for 12 weeks (Rat-A-PED), or from sedentary age-matched cage controls. Second harmonic generation and multiphoton excitation fluorescence were performed simultaneously on these tissue sections in at least three different areas.
SHG microscopy revealed an association between abnormal tenocyte morphology and morphological changes in the fibrillar collagen matrix of mechanically loaded Achilles tendons. Collagen density and organization was significantly reduced in focal micro-regions of mechanically loaded tendons. These pathological changes occurred specifically in association with altered tenocyte morphology. Normal tendons displayed a regular distribution of fibre bundles, and the average size of these bundles as determined by Gaussian analysis was 0.47 μm ± 0.02. In comparison, fibre bundle measures from tendon regions in the vicinity of abnormal tenocytes could not be quantified due to a reduction in their regularity of distribution and orientation.
SHG microscopy allowed high resolution detection of focal tendon abnormalities affecting the fibrillar collagen matrix. With ongoing repetitive loading, these tenocyte-associated focal collagen defects could predispose to the progression of overuse pathology.
肌腱细胞被认为与肌腱病的发生有关，肌腱病是一种常见于肌肉骨骼过度使用综合征的慢性疾病。然而，异常的肌腱细胞形态与纤维胶原基质的早期变化之间的关系尚未在体内进行密切检查。二次谐波产生（SHG）显微镜是一种最近开发的技术，它可以高度特异性和分辨率地检查纤维胶原结构。本研究的目的是研究 SHG 和多光子激发荧光（MPEF）显微镜在理解早期肌腱过度使用病变中肌腱细胞与其周围胶原基质之间关系的潜在应用。
从接受跟腱加载方案 12 周的成年雄性 Sprague-Dawley 大鼠（Rat-A-PED）或久坐不动的同龄笼对照中制备肌腱的组织学标本。在这些组织切片上同时进行二次谐波产生和多光子激发荧光。
SHG 显微镜显示，异常的肌腱细胞形态与机械加载的跟腱纤维胶原基质的形态变化之间存在关联。在机械加载的跟腱的焦点微区中，胶原密度和组织显著降低。这些病理变化仅与改变的肌腱细胞形态有关。正常的肌腱显示纤维束的规则分布，并且通过高斯分析确定的这些束的平均大小为 0.47μm±0.02。相比之下，来自邻近异常肌腱细胞的肌腱区域的纤维束测量值由于其分布和取向的规则性降低而无法量化。
SHG 显微镜允许对影响纤维胶原基质的焦点肌腱异常进行高分辨率检测。随着持续的重复加载，这些与肌腱细胞相关的焦点胶原缺陷可能会导致过度使用病理的进展。
