Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA.
Ann Anat. 2011 Jul;193(4):354-61. doi: 10.1016/j.aanat.2011.02.013. Epub 2011 Mar 12.
Full functional recovery after traumatic peripheral nerve injury is rare. We postulate three reasons for the poor functional outcome measures observed. Axon regeneration is slow and not all axons participate. Significant misdirection of regenerating axons to reinnervate inappropriate targets occurs. Seemingly permanent changes in neural circuitry in the central nervous system are found to accompany axotomy of peripheral axons. Exercise in the form of modest daily treadmill training impacts all three of these areas. Compared to untrained controls, regenerating axons elongate considerably farther in treadmill trained animals and do so via an autocrine/paracrine neurotrophin signaling pathway. This enhancement of axon regeneration takes place without an increase in the amount of misdirection of regenerating axons found without training. The enhancement also occurs in a sex-dependent manner. Slow continuous training is effective only in males, while more intense interval training is effective only in females. In treadmill trained, but not untrained mice the extent of coverage of axotomized motoneurons is maintained, thus preserving important elements of the spinal circuitry.
创伤性周围神经损伤后很难完全恢复功能。我们提出了观察到的功能结果测量不佳的三个原因。轴突再生缓慢，并非所有轴突都参与再生。再生轴突会发生明显的错误导向，重新支配不合适的靶标。在外周轴突切断后，中枢神经系统中的神经回路似乎会发生永久性变化。以适度每日跑步机训练形式的运动影响了这三个方面。与未经训练的对照组相比，在跑步机训练的动物中，再生轴突显著延长了相当长的距离，并且通过自分泌/旁分泌神经营养因子信号通路进行。这种轴突再生的增强不会增加未经训练时发现的再生轴突的错误导向。这种增强也以性别依赖性的方式发生。缓慢持续训练仅对雄性有效，而更强烈的间歇训练仅对雌性有效。在跑步机训练的老鼠中，但不是在未经训练的老鼠中，轴突切断的运动神经元的覆盖范围得以维持，从而保留了脊髓回路的重要元素。
