운동이 좌골신경 손상 F344쥐의 Neurotrophins, BDNF, NT-3, GAP-43 단백질 발현과 축삭재생에 미치는 영향

Abstract

본 연구에서는 흰쥐의 좌골신경을 손상시킨 후 트레드밀 운동을 적용하여 신경돌기 성장과 좌골신경의 축삭 재생 및 신경성장 인자 발현 그리고 신경기능지수의 변화를 연구했다. 본 연구결과 좌골손상 후 트레드밀 운동을 실시한 그룹이 비운동군에 비해 축삭재생이 촉진되었고, 원위부의 좌골신경에서도 NGF, BDNF단백질 발현이 상당히 증가된 것으로 나타났다. 또한 좌골신경지수를 검사한 결과에서도 운동을 실시한 흰쥐가 비운동 흰쥐에 비해 기능적 회복이 상당히 빠른 것으로 나타났다. 이러한 결과는 좌골손상 후 운동의 실시가 좌골신경의 축삭재생 촉진과 신경영양인자의 발현증가를 통해 기능적 회복에 도움이 될 수 있음을 보여주는 것이다. Peripheral nerve injuries are a commonly encountered clinical problem and often result in severe functional deficits. In the present study, the effects of treadmill exercise on neurotrophin expressions and functional recovery following sciatic crushed nerve injury were investigated. Animals were randomly assigned into four groups: the sciatic nerve injury group, the sciatic nerve injury and 3-day-exercise, the sciatic nerve injury and 7-days-exercise, and the sciatic nerve injury and 14-days-exercise groups. Sciatic nerve injury was caused by crushing the right sciatic nerve for 30 s using a surgical clip. A the light-exercise was applied to each of the exercise group over the respective number of days. In the present results, we identified enhanced axonal re-growth in the distal stump of the sciatic nerve 3-14 days after crush injury with treadmill training. Dorsal root ganglion (DRG) neuron when cultured from animals with nerve injury and treadmill training showed more enhanced neurite outgrowth than that of sedentary animals. Nerve growth factor (NGF) protein levels in low-intensity treadmill training group were highly induced in the injured sciatic nerves 3, 7 and 14 days after injury compared with sedentary group, and brain-derived neurotrophin factor (BDNF) protein levels in treadmill exercise group were highly induced in the injured sciatic nerve 3 days after injury compared with sedentary group. Then, treadmill exercise increased neurotrophic factors induced in the regenerating nerves. We further demonstrate that motor functional recovery after sciatic nerve injury was promoted by treadmill exercise. Thus, the present data provide a new evidence that treadmill exercise enhanced neurotrophins expression and axonal regeneration after sciatic nerve injury in rats.