Purpose

To examine healing adaptations over 17 weeks post Achilles tendon (AT) rupture in the injured region (IR) compared to an uninjured region (UIR) of the AT.

Methods

Twenty-four rats were subjected to a complete right-sided AT rupture, while the left side served as a control. ATs were harvested at 1, 2, 8 and 17 weeks post-rupture and stained with antibodies specific to Collagen type I (Col I) and II (Col II) as well as Alcian Blue and Picrosirius Red staining techniques. Histopathological changes, proteoglycan content, collagen alignment and immunoexpression were assessed.

Results

Both regions examined, IR and UIR, exhibited over weeks 1–17 similar healing adaptations of increasing collagen alignment, decreasing Col I immunoexpression, as well as increasing proteoglycan content and Col II occurrence. Increased proteoglycan content was found already at week 2 in the UIR, while it first increased at week 8 in the IR. The area positive to Col II was increased compared to controls at week 8 in the UIR, whereas it first raised at week 17 in the IR. Collagen disorganization successively declined to reach control levels at week 17 in the UIR, but was still higher in the IR.

Conclusion

This study demonstrated that uninjured areas of the AT remote from the rupture site also undergo pronounced remodeling, although with time-span differences relative to injured AT portions. These changes including the pathologic heterotopic mineralization and chondrogenic differentiation observed in both regions may have implications in the choice of rehabilitation regimes in order to prevent secondary rupture.

中文翻译：

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大鼠跟腱完全中部破裂会导致未受伤区域发生远距离和时间不匹配的变化。

目的

为了检查跟腱（AT）的未受伤区域（UIR）相比，跟腱（AT）断裂后17周内的愈合适应情况。

方法

24只大鼠遭受完全的右侧AT破裂，而左侧作为对照。在破裂后1、2、8和17周收集AT，并用对I型胶原蛋白（Col I）和II型胶原蛋白（Col II）特异的抗体以及阿尔辛蓝和皮克罗西鲁斯红染色技术进行染色。评估组织病理学变化，蛋白聚糖含量，胶原蛋白排列和免疫表达。

结果

被检查的两个区域，IR和UIR，在1到17周内均表现出相似的愈合适应性变化，即胶原排列增加，Col I免疫表达降低，蛋白聚糖含量和Col II发生率增加。在UIR的第2周发现蛋白聚糖含量增加，而在IR的第8周首次发现蛋白聚糖含量增加。与UIR第8周的对照组相比，Col II阳性区域增加了，而IR中在第17周首次增加。UIR第17周的胶原蛋白解体顺序下降至控制水平，但IR仍较高。

结论

这项研究表明，距破裂部位较远的AT的未受伤区域也经历了明显的重塑，尽管相对于受伤的AT部分而言时间跨度有所不同。这些变化，包括在两个地区观察到的病理性异位矿化和软骨形成分化，都可能对康复方案的选择产生影响，以防止继发性破裂。