Scanning electron microscopic characterization of healing and normal rat ligament microstructure under slack and loaded conditions
Scanning electron microscopic characterization of healing and normal rat ligament microstructure under slack and loaded conditions
复制标题
DOI：
10.1080/03008200390200193
复制
发表时间：
2003-03-01
影响因子：
2.9
通讯作者：
Vanderby, R
中科院分区：
文献类型：
--
作者：
Hurschler, C;Provenzano, PP;Vanderby, R
本研究的目的是观察和比较正常和愈合韧带中胶原纤维微观结构的行为，包括原位和离体，以深入了解正常和愈合韧带中的结构-功能关系。对26只雄性大鼠的52条韧带进行了研究。11只动物接受了双侧内侧副韧带（MCL）（22条韧带）的手术横断，并使其愈合2周。另外15只动物（30条韧带）用作正常动物。将韧带分为6组：松弛（n = 6对照，n = 6愈合），参比（n = 4对照，n = 4愈合），负载（n = 4例对照，n = 4例愈合），15度屈曲（n = 4对照，n = 4愈合），120度扭转（n = 4对照，n = 4愈合），以及组织应变与扭转角（n = 8正常）。除组织应变与韧带角度组外，所有韧带均准备用于扫描电子显微镜检查。采集组织，将其固定在载荷架上，并在以下五种状态之一中进行化学固定：（1）松弛，（2）参考（加载开始），（3）加载，（4）15度膝关节屈曲，或（5）120度膝关节屈曲。固定后，制备组织用于电子显微镜检查（SEM）。松弛组、参照组和加载组的显微照片显示，正常韧带以及愈合韧带的瘢痕和"回缩"区域中的纤维在加载下变直。胶原纤维的直径和卷曲模式在愈合韧带的瘢痕区域发生了显著变化：宽度从19.4 +/-1.7 μ m减小到6.5 +/-2.1 μ m（p <.000001），周期从51.4 +/-15.1 μ m到11.0 +/-2.4 μ m（p <.000001），振幅从9.8 +/-0.8 μ m到3.9 +/-0.8 μ m（p <.000001）。正常的韧带在屈曲120 °时呈波浪状，但在屈曲15 °时波浪状较少。原位固定的愈合韧带在120 °和15 °屈曲时的瘢痕区域中显示纤维波纹区域，表明韧带松弛持续朝向活动范围的两个极端。这些数据表明，卷曲纤维的拉直是一种功能相关的现象，不仅在正常的韧带中，而且在愈合的韧带中。
The objective of this study was to observe and compare behavior of the collagen fiber microstructure in normal and healing ligaments, both in situ and ex vivo, in order to add insight into the structure-function relationship in normal and healing ligaments. Fifty-two ligaments from 26 male rats were investigated. Eleven animals underwent surgical transection of both medial collateral ligaments (MCLs) (22 ligaments), which were allowed to heal for a period of 2 weeks. An additional 15 animals (30 ligaments) were used as normals. Ligaments were placed into six groups: Slack ( n = 6 control, n = 6 healing), Reference ( n = 4 control, n = 4 healing), Loaded ( n = 4 control, n = 4 healing), 15degrees Flexion ( n = 4 control, n = 4 healing), 120degrees Flexion ( n = 4 control, n = 4 healing), and Tissue Strain vs. Flexion Angle ( n = 8 normals). All ligaments, except those in the Tissue Strain vs. Flexion Angle group, were prepared for scanning electron microscopy. Tissues were harvested, mounted in a load frame, and chemically fixed in one of five states: (1) slack, (2) reference (onset of loading), (3) loaded, (4) 15degrees knee flexion, or (5) 120degrees knee flexion. After fixation the tissues were prepared for electron microscopy (SEM). The micrographs from the slack, reference, and loaded groups show fiber straightening with loading in normal ligaments as well as in both scar and "retracted" regions of healing ligaments. Collagen fibers' diameter and crimp patterns were dramatically changed in the scar region of healing ligaments: Width decreased from 19.4 +/- 1.7 mum to 6.5 +/- 2.1 mum ( p < .000001), period from 51.4 +/- 15.1 mum to 11.0 +/- 2.4 mum ( p < .000001), and amplitude from 9.8 +/- 0.8 mum to 3.9 +/- 0.8 mum ( p < .000001). Normal ligaments fixed in situ show wavy regions at 120degrees but less so at 15degrees flexion. Healing ligaments fixed in situ show regions of fiber waviness in the scar region at 120degrees and also at 15degrees flexion, indicating ligament laxity persists toward both extremes of the range of motion. The data suggest that straightening of crimped fibers is a functionally relevant phenomenon, not only in normal but also in healing ligaments.