Studies of the Effects of Acupuncture Stimulation at Huatuo Jiaji(EX B2) Points on Axonal Regeneration of Injured Sciatic Nerve in the Rats

화타협척혈 침자극에 의한 손상 말초신경의 재생효과에 관한 연구

Objectives : The present study was performed to investigate whether acupuncture stimulation in the rats affected regeneration properties of the injured sciatic nerve. A differential effect of acupuncture stimulation on the one point near the spinal nerve root controlling sciatic nerve activity and the other point in the peripheral area subordinated by injured nerve was compared. Materials and Methods: Rat sciatic nerves were injured by crush, and the effects on axonal regeneration on injured sciatic nerves were evaluated by acupuncture stimulation at two different regions. In proximal acupuncture stimulation group, acupuncture stimulation was performed on Huatuo Jiaji(EX B2) points located from L5 to S1 vertebral levels to stimulate the nearest spinal nerve root that innervates sciatic nerves. In distal acupuncture stimulation group, acupuncture stimulation was performed on Zusanli(ST 36) and Weizhong(BL 40) points to stimulate at peripheral area dominated by injured sciatic nerves. Acupuncture stimulation was given every other days for 1 or 2 weeks. Sciatic nerve tissues collected from acupuncture stimulation experimental groups, injury control group, and intact animal group were used for protein analysis by Western blotting or Hoechst nuclear staining. To determine axonal regeneration, Dil fluorescence dye was injected into the sciatic nerve 0.5 cm distal to the injury site in individual animal groups and Dil-labeled cells by retrograde tracing were measured in the DRG at lumbar 5 or in the spinal cord. DRG sensory neurons prepared from individual animal groups were used to measure the extent of neurite outgrowth and for immunofluorescence staining with anti-GAP-43 antibody. Results : Animal groups given proximal or distal acupuncture stimulation showed upregulation of GAP-43 and Cdc2 protein levels in the sciatic nerve at 7 days after injury. Cdk2 protein levels were strongly induced by nerve injury, but did not show changes by acupuncture stimulation. Phospho-Erk1/2 protein levels were elevated by acupuncture stimulation above those present in the injury control animals. These increase in regeneration-associated protein levels appeared to be related with increase cell proliferation in the injured sciatic nerves. Hoechst 33258 staining of sciatic nerve tissue to visualize nuclei of individual cells showed increased Schwann cell number in the distal portion of the injured nerve 7 and 14 days after injury and further increases by acupuncture stimulation particularly at the proximal position. Measurement of axonal regeneration by retrograde tracing showed significantly increased Dil-labeled cells in proximal acupuncture stimulation group compared to distal acupuncture stimulation group and injury control group. Finally, an evaluation of axonal regeneration by retrograde tracing showed increased number of Dil labeled cells in the DRG at lumbar 5 or in the ventral horn of the spinal cord at lower thoracic level at 7 days after nerve injury. Conclusions : The present data show that the proximal acupuncture stimulation at Huatuo Jiaji(EX B2) points governing injured sciatic nerves was more effective for axonal regeneration than the distal acupuncture stimulation. Further studies on functional recovery or associated molecular mechanisms should be critical for developing animal models and clinical applications.

목적 : 좌골신경 압좌손상으로 유발된 쥐의 모델을 이용하여 손상된 말초신경의 재생효과에 관한 침자극 효과를 세포분자학적, 조직학적 관점에서 연구하였다. 아울러 손상 좌골신경을 지배하는 척수신경근과 가까운 부위 경혈자극과 좌골신경이 지배하는 말초부위 경혈자극과의 침자극 효과를 비교 연구하였다. 방법 : 한쪽 좌골신경에 압좌손상을 유발 한 실험쥐들을 1주, 2주로 나눈 뒤 각각에 대해 격일로 1주군은 3회, 2주군은 6회의 침자극을 시행하였다. 손상 좌골신경의 재생효과를 비교실험하기 위해 정상군, 압좌손상만을 유발한 실험군, 침자극 군으로 나누었다. 침자극 군 중 한 군은 손상신경을 지배하는 척수신경근에 가장 가까운 2개의 화타협척혈(EX B2)에 자침(근위부 자극군)하였고, 다른 한 군은 말초부위에 위치한 족삼리혈(ST 36)과 위중혈(BL 40) 2곳에 자침(원위부 자극군)하였다. 실험 후 각각의 조직을 분리하여 Western blotting 혹은 Hoechst staining으로 Gap-43, Cdc2, Cdk2, Erk1/2 단백질을 분석 및 좌골신경의 각 세포수를 측정하였다. Retrograde tracing을 통해 L5의 DRG와 척수에서 말초신경 재생 효과를 관찰하였고, Immunofluorescence staining을 통해 신경돌기 가지의 신장 정도를 파악하였다. 결과 : 좌골신경 손상 7일된 실험쥐의 근위부와 원위부 침자극군에서 GAP-43와 Cdc2 단백질수준이 향상된 것으로 나타났다. Cdk2 단백질수준은 압좌손상 실험군에서 강하게 증가하였지만 침자극군과 비교해서 별다른 차이는 보이지 않았다. Phospho-Erk1/2 단백질수준은 침자극군에서 향상된 것으로 나타났다. 손상 7일과 14일 된 실험쥐의 손상 원위부에서 슈반세포 수가 증가하였으며 특히 근위부 침자극군에서 더욱 증가한 것으로 나타났다. Retrograde tracing을 이용한 검사 결과 침자극군에서 L5의 DRG와 척수의 염색 세포 수가 증가된 것으로 나타나 침자극이 축삭재생에 효과적인 것으로 나타났다. L5의 DRG 감각신경의 신경돌기 가지 신장정도 및 GAP-43 단백질의 발현 정도를 측정한 결과 근위부 침자극군에서 효과적으로 GAP-43 단백질의 발현 및 신경돌기 가지가 신장된 것으로 나타났다. 결론 : 본 실험결과 침치료가 손상 좌골신경의 재생에 효과적인 것으로 보여지며, 특히 손상된 좌골신경을 지배하는 척수신경근 주위 화타협척혈에 대한 침자극이 말초부위의 침자극에 비해 신경재생에 더욱 효과적인 것으로 나타났다.