Biomechanics Laboratory, Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Aichi, Japan.
Department of Health Science, Hokkaido Chitose College of Rehabilitation, Chitose, Hokkaido, Japan.
J Orthop Res. 2024 Mar;42(3):607-617. doi: 10.1002/jor.25705. Epub 2023 Nov 5.
Adult mammals are known for their poor ability to regenerate tissues, including tendons. On the other hand, urodeles have become an important model in regenerative studies for their remarkable ability to regenerate various body parts and organs throughout life, such as limbs, retinas, or even the brain. However, little is known about their capacity to regenerate injured tendons. If newts can also repair tendons without scar formation, they may be a suitable animal model for tendon regeneration studies in other adult vertebrates. Therefore, the present study used Iberian ribbed newts to characterize mechanical and structural regeneration of tendons following transection, using tensile tests and multiphoton microscopy. A digital flexor tendon in a hindlimb was transected either partially or completely, and regenerated tendon was examined 6 and 12 weeks after the operation. Tensile strength of regenerated tendons was significantly less than normal at 6 weeks, but was remarkably recovered at 12 weeks, reaching levels comparable to those of uninjured tendons. On the other hand, mouse tendons demonstrated poor recovery of strength even after 12 weeks. Multiphoton microscopy revealed that tendon-like collagenous tissue bridges residual tendon stubs in newts, but disorganized scar-like tissue filled the injured location in mice. These findings highlight the remarkable capacity of newts to recover from tendon injury and confirm the utility of newts as a model to study tendon regeneration.
成年哺乳动物的组织再生能力较差，这包括肌腱。另一方面，蝾螈因其在一生中具有显著的再生各种身体部位和器官的能力，例如肢体、视网膜，甚至大脑，成为再生研究中的重要模型。然而，关于它们损伤肌腱的再生能力知之甚少。如果蝾螈也可以在不形成疤痕的情况下修复肌腱，那么它们可能是其他成年脊椎动物肌腱再生研究的合适动物模型。因此，本研究使用伊比利亚肋突螈来描述肌腱横断后的机械和结构再生，使用拉伸试验和多光子显微镜进行研究。后肢的一个数字屈肌腱被部分或完全横断，并且在手术后 6 和 12 周检查再生的肌腱。再生肌腱的拉伸强度在 6 周时明显低于正常水平，但在 12 周时显著恢复，达到与未受伤肌腱相当的水平。另一方面，即使在 12 周后，小鼠肌腱的强度恢复也很差。多光子显微镜显示，肌腱样胶原组织桥接了蝾螈残余肌腱残端，但在小鼠中，受伤部位充满了紊乱的疤痕样组织。这些发现强调了蝾螈从肌腱损伤中恢复的惊人能力，并证实了蝾螈作为研究肌腱再生模型的实用性。
