不同电针介入时机对模型大鼠腰多裂肌损伤修复的影响及机制研究

Posterior lumbar surgery is currently the most used approach to deal with intervertebral disc resection, spinal canal decompression and intervertebral segment fusion, however, iatrogenic injury of the paraspinal multifidus muscles has become a new source of low back pain and disability in those postoperative patients. Our research had found that electroacupuncture could promote the expression of Pax-7、Myod and p-Akt in multifidus muscle stem cells——muscle satellite cells (Muscle satellite, cells, MSCs) , thus to accelerate the repairation of the injured multifidus muscles. Yet, the best intervention time of electroacupuncture after muscle injury is not clear, and the specific mechanism remains to be further elucidated. Recently, as an important downstream target of PI3K-Akt pathway, FoxO1 was found to be closely related to the proliferation of MSCs as it could regulate cell cycle protein p57 and Gadd45α. We intend to observe the effects of different electroacupuncture intervention time after muscle injury in a rat model by transmission electron microscopy, morphology and molecular biology and verify the best intervention time. Moreover, the mechanism of PI3K-Akt-FoxO1 pathway will be further explored to explain the effect of electroacupuncture. Our study will provide feasible scheme and scientific basis for the clinical application of electroacupuncture to promote the rehabilitation of multifidus muscles after operation.

腰椎后路手术是目前进行椎间盘切除、椎管减压及椎体节段间融合的主要手术方法，而术中对脊旁多裂肌的医源性损伤却成为病人术后腰背痛和功能障碍的新来源。课题组前期发现，电针干预可促进多裂肌干细胞——肌卫星细胞（Muscle satellite cells, MSCs）Pax-7、Myod、p-Akt的表达，加速损伤多裂肌的修复，但术后电针干预的最佳时机尚无定论，且其具体机制仍待进一步阐释。近期有研究发现，作为PI3K-Akt下游重要靶分子，FoxO1可调控细胞周期蛋白p57、Gadd45α的表达，与MSCs的增殖密切相关。我们拟复制大鼠多裂肌损伤模型，从透射电镜、形态学、分子生物学三方面观察造模后不同时间点电针干预对损伤多裂肌修复的影响，筛选电针干预的最佳时机，并进一步分析PI3K-Akt-FoxO1通路在电针起效过程中的作用机制，为临床应用电针促进术后多裂肌的修复提供可行方案和科学依据。

腰椎后路手术是目前进行椎间盘切除、椎管减压及椎体节段间融合的主要手术方法，而术中对脊旁多裂肌的医源性损伤却成为病人术后腰背痛和功能障碍的新来源。我们前期发现，电针干预可促进多裂肌干细胞——肌卫星细胞（Muscle satellite cells, MSCs）Pax-7、Myod、p-Akt的表达，加速损伤多裂肌的修复，但术后电针干预的最佳时机尚无定论，且其具体机制仍待进一步阐释。本课题复制大鼠多裂肌损伤模型，从透射电镜、形态学、分子生物学三方面观察造模后不同时间点电针干预对损伤多裂肌修复的影响，筛选电针干预的最佳时机，并进一步分析PI3K-Akt-FoxO1通路在电针起效过程中的作用机制。研究结果：免疫组化及Western-blot结果发现与造模后即刻电针及造模后48h电针相比，造模后24h开始电针可显著改善受损多裂肌组织的形态学，并提高CDK4、P57、Myod、FoxO1等多裂肌增殖分化相关蛋白的表达，初步表明多裂肌损伤后的最佳电针干预时间点为损伤后24h。我们进一步在体外以电针血清培养多裂肌卫星细胞，发现用抑制剂阻断PI3K-Ak通路后，电针血清的促多裂肌增殖效应被阻断，Pax7、Myod等多裂肌卫星细胞增殖相关蛋白水平出现了明显下调，p-Akt的表达亦出现了明显下降。以上结果初步表明，电针促进多裂肌修复的最佳介入时机为损伤后24h，其机制与激活PI3K-Akt-FoxO1通路并调控细胞周期有关。