Neonatal Spinal Cord Transection Decreases Hindlimb Weight-Bearing and Affects Formation of Achilles and Tail Tendons
Neonatal Spinal Cord Transection Decreases Hindlimb Weight-Bearing and Affects Formation of Achilles and Tail Tendons
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DOI：
10.1115/1.4050031
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发表时间：
2021-06-01
影响因子：
1.7
通讯作者：
Schiele，Nathan R.
中科院分区：
文献类型：
--
作者：
Theodossiou，Sophia K.;Pancheri，Nicholas M.;Schiele，Nathan R.
适当的肌腱形成可能需要机械负载。然而，目前尚不清楚新生儿负重运动活动的发展如何影响肌腱的形成。本研究评估了新生大鼠在出生后（P）1 接受低胸脊髓横断或假手术的肌腱机械特性以及随之而来的负重运动变化。在第 10 页，评估脊髓横断和假手术对照组的自发运动，以确定对负重后肢运动的影响。对作为代表性储能、承重肌腱的 P10 跟腱 (AT) 和作为代表性位置、非承重肌腱的尾腱 (TT) 的机械性能进行了评估。与假手术对照组相比，脊髓横断大鼠的非负重和部分负重后肢活动减少。没有脊髓横断的大鼠表现出完全负重运动。与假手术大鼠相比，脊髓横断大鼠的 AT 弹性模量增加，而横截面积趋于降低。脊髓横断大鼠的 TT 具有更高的硬度和横截面积。 AT 和 TT 的胶原结构似乎不受手术条件的影响，并且胶原卷曲模式没有检测到显着差异。我们的研究结果表明，发育过程中负重运动活动产生的机械负荷调节新生儿 AT 侧向扩张并维持肌腱顺应性，并且 TT 可能受到差异性调节。新生儿负重运动的开始和逐渐增加可能提供指导功能性产后肌腱形成所需的机械负荷。
Mechanical loading may be required for proper tendon formation. However, it is not well understood how tendon formation is impacted by the development of weight-bearing locomotor activity in the neonate. This study assessed tendon mechanical properties, and concomitant changes in weight-bearing locomotion, in neonatal rats subjected to a low thoracic spinal cord transection or a sham surgery at postnatal day (P)1. On P10, spontaneous locomotion was evaluated in spinal cord transected and sham controls to determine impacts on weight-bearing hindlimb movement. The mechanical properties of P10 Achilles tendons (ATs), as representative energy-storing, weight-bearing tendons, and tail tendons (TTs), as representative positional, non-weight-bearing tendons were evaluated. Non- and partial weight-bearing hindlimb activity decreased in spinal cord transected rats compared to sham controls. No spinal cord transected rats showed full weight-bearing locomotion. ATs from spinal cord transected rats had increased elastic modulus, while cross-sectional area trended lower compared to sham rats. TTs from spinal cord transected rats had higher stiffness and cross-sectional area. Collagen structure of ATs and TTs did not appear impacted by surgery condition, and no significant differences were detected in the collagen crimp pattern. Our findings suggest that mechanical loading from weight-bearing locomotor activity during development regulates neonatal AT lateral expansion and maintains tendon compliance, and that TTs may be differentially regulated. The onset and gradual increase of weight-bearing movement in the neonate may provide the mechanical loading needed to direct functional postnatal tendon formation.