Department of Orthopedic Surgery, Spine Center, Changzheng Hospital, Second Military Medical University, No.415 Fengyang Road, Shanghai, 200003, People's Republic of China.
Department of Orthopedic Surgery, Spine Center, Changzheng Hospital, Second Military Medical University, No.415 Fengyang Road, Shanghai, 200003, People's Republic of China.
Biochem Biophys Res Commun. 2020 Jun 18;527(1):131-137. doi: 10.1016/j.bbrc.2020.04.094. Epub 2020 Apr 28.
To investigate the expression of Nogo-A in dorsal root ganglion (DRG) in rats with cauda equina injury and the therapeutic effects of blocking Nogo-A and its receptor.
Fifty-eight male Sprague-Dawley rats were divided randomly into either the sham operation group (n = 24) or the cauda equina compression (CEC) control group (n = 34). Behavioral, histological, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analyses were conducted to assess the establishment of the model. The dynamic expression change of Nogo-A was evaluated using real time-qPCR. Immunofluorescence was used to evaluate the expression of Nogo-A in the DRG and cauda equina. Furthermore, 20 male Sprague-Dawley rats were equally divided into 4 groups, including the sham group, the CEC group, the NEP1-40 (the NgR antagonist peptide) treatment group, and the JTE-013 (the S1PR2 antagonist) treatment group. Behavioral assessments and western blotting were used to evaluate the therapeutic effect of cauda equina injury via blocking Nogo-A and its receptor.
Tactile allodynia and heat hyperalgesia in the CEC model developed as soon as 1 day after surgery and recovered to normal at 7 days, which was followed by the downregulation of Nogo-A in DRG neurons. However, the locomotor function impairment in the CEC model showed a different prognosis from the sensory function, which was consistent with the expression change of Nogo-A in the spinal cord. Immunofluorescence results also demonstrated that Nogo A-positive/NF200-negative neurons and axons increased in the DRG and cauda equina 7 days after surgery. Surprisingly, Schwann cells, which myelinate axons in the PNS, also expressed considerable amounts of Nogo-A. Then, after blocking the Nogo-A/NgR signaling pathway by NEP1-40, significant improvement of mechanical allodynia was identified in the first 2 days after the surgery. Western blotting suggested the NEP1-40 treatment group had lower expression of cleaved caspase-3 than the CEC and JTE-013 treatment group.
Neuronal Nogo-A in the DRG may be involved in regeneration and play a protective role in the CEC model. Whereas Nogo-A, released from the injured axons or expressed by Schwann cells, may act as an inhibiting factor in the process of CEC repairment. Thus, blocking the Nogo-A/NgR signaling pathway can alleviate mechanical allodynia by apoptosis inhibition.
研究轴索损伤后背根神经节（DRG）中 Nogo-A 的表达及阻断 Nogo-A 及其受体的治疗作用。
58 只雄性 Sprague-Dawley 大鼠随机分为假手术组（n=24）或马尾压迫（CEC）对照组（n=34）。通过行为学、组织学和末端脱氧核苷酸转移酶 dUTP 缺口末端标记（TUNEL）分析来评估模型的建立。采用实时 qPCR 评估 Nogo-A 的动态表达变化。免疫荧光法评价 DRG 和马尾中 Nogo-A 的表达。此外，将 20 只雄性 Sprague-Dawley 大鼠等分为 4 组，包括假手术组、CEC 组、NEP1-40（NgR 拮抗剂肽）治疗组和 JTE-013（S1PR2 拮抗剂）治疗组。通过行为学评估和 Western blot 检测，评估阻断 Nogo-A 及其受体对马尾损伤的治疗作用。
CEC 模型术后 1 天出现触觉过敏和热痛觉过敏，7 天恢复正常，随后 DRG 神经元中 Nogo-A 下调。然而，CEC 模型的运动功能障碍与感觉功能障碍的预后不同，这与脊髓中 Nogo-A 的表达变化一致。免疫荧光结果还表明，术后 7 天 DRG 和马尾中 Nogo A 阳性/NF200 阴性神经元和轴突增加。令人惊讶的是，在周围神经系统中对轴突起髓鞘作用的雪旺细胞也表达了相当数量的 Nogo-A。然后，通过 NEP1-40 阻断 Nogo-A/NgR 信号通路，术后第 2 天即可显著改善机械性痛觉过敏。Western blot 表明，NEP1-40 治疗组 cleaved caspase-3 的表达低于 CEC 和 JTE-013 治疗组。
DRG 中的神经元 Nogo-A 可能参与了再生，并在 CEC 模型中发挥了保护作用。而轴突损伤释放或雪旺细胞表达的 Nogo-A 可能在 CEC 修复过程中起抑制作用。因此，阻断 Nogo-A/NgR 信号通路可通过抑制细胞凋亡来减轻机械性痛觉过敏。
