Department Spinal Surgery, Jinan Central Hospital Affiliated to Shandong University, 105 Jiefang Road, Jinan, 250013, Shandong, China.
Department Emergency Medicine, Taishan Medical University, Taian, 271016, Shandong, China.
Neurochem Res. 2018 Aug;43(8):1641-1649. doi: 10.1007/s11064-018-2580-1. Epub 2018 Jun 22.
To assess the therapeutic effects of microRNA-21 (miR-21) knockdown (KD) for acute thoracic spinal cord contusion using a mouse model. Forty C57/BL6 mice were randomly divided into four groups: mice in the sham-operated (Sham) group received surgical procedure without spinal cord contusion; the spinal cord injury (SCI) group mice underwent spinal cord contusion without treatment; mice in the miR-21 KD group underwent spinal cord contusion followed by a single dose subdural injection of miR-21 KD vectors (1 × 10 TU); and the negative control (NC) group mice were given subdural injection of comparable amount of NC vectors (1 × 10 TU) after spinal cord contusion. The Basso Mouse Scale (BMS) was employed to assess hindlimb motor functions. Hematoxylin-eosin and Luxol fast blue staining were performed to evaluate pathologic changes in spinal cord tissues. Peripheral blood serum levels of tumor necrosis factor α (TNFα), transforming growth factor β (TGF-β) and interleukin-1β (IL-1β) were determined by the enzyme-linked immunosorbent assay, and mRNA expression of Brain derived neurotrophic factor (BDNF) was examined by reverse transcription-polymerase chain reaction (RT-PCR). Western blotting was performed to analyze the AKT signaling pathway. KD of miRNA-21 effectively improved the BMS scores at day 14 post-surgery compared with the SCI group (p < 0.01). The spinal cord tissue in the miR-21 KD group displayed the most overt histologic signs of recovery, with axonal regeneration and the recovery of neuronal morphology at day 14 post-surgery. Significantly alleviation of TGF-β1, TNF-α and IL-1β was also found in sera from the miR-21 inhibition group in comparison to others, whereas BDNF gene expression was upregulated following miR-21 KD (p < 0.01). Further, significantly decreased AKT phosphorylation activity was illustrated in the miR-21 KD group (p < 0.001). The data suggest that miR-21 KD significantly reduces the inflammatory response at the damaged spinal cord site and promotes motor functional recovery. The treatment also elevated expression of BDNF, a neurotrophin participating in nerve regeneration.
为了评估 miR-21（miR-21）敲低（KD）对小鼠急性胸段脊髓挫伤模型的治疗效果。将 40 只 C57/BL6 小鼠随机分为 4 组：假手术（Sham）组小鼠接受手术但不进行脊髓挫伤；脊髓损伤（SCI）组小鼠进行脊髓挫伤但不进行治疗；miR-21 KD 组小鼠进行脊髓挫伤后单次硬膜下注射 miR-21 KD 载体（1×10 TU）；阴性对照（NC）组小鼠在脊髓挫伤后接受相同量的 NC 载体（1×10 TU）硬膜下注射。Basso 小鼠步态评分（BMS）用于评估后肢运动功能。苏木精-伊红和卢索快速蓝染色评估脊髓组织的病理变化。酶联免疫吸附试验测定外周血清肿瘤坏死因子-α（TNFα）、转化生长因子-β（TGF-β）和白细胞介素-1β（IL-1β）水平，逆转录-聚合酶链反应（RT-PCR）检测脑源性神经营养因子（BDNF）mRNA 表达。Western blot 分析 AKT 信号通路。与 SCI 组相比，miR-21 KD 组术后 14 天 BMS 评分明显提高（p<0.01）。miR-21 KD 组脊髓组织在术后 14 天显示出最明显的组织学恢复迹象，轴突再生和神经元形态恢复。与其他组相比，miR-21 抑制组血清中 TGF-β1、TNF-α 和 IL-1β 明显减轻，而 BDNF 基因表达上调（p<0.01）。进一步表明，miR-21 KD 组 AKT 磷酸化活性明显降低（p<0.001）。结果表明，miR-21 KD 显著减轻损伤脊髓部位的炎症反应，促进运动功能恢复。该治疗还提高了神经营养因子 BDNF 的表达，BDNF 参与神经再生。
