Dey Soumil, Bose Samrat, Kumar Suneel, Rathore Ravinder, Mathur Rashmi, Jain Suman
a Department of Physiology , All India Institute of Medical Sciences , New Delhi , India.
b Department of Microbiology , All India Institute of Medical Sciences , New Delhi , India.
Electromagn Biol Med. 2017;36(4):330-340. doi: 10.1080/15368378.2017.1389750. Epub 2017 Nov 15.
Spinal cord injury (SCI) is insult to the spinal cord, which results in loss of sensory and motor function below the level of injury. SCI results in both immediate mechanical damage and secondary tissue degeneration. Following traumatic insult, activated microglia release proinflammatory cytokines and excess iron due to hemorrhage, initiating oxidative stress that contributes to secondary degeneration. Literature suggests that benefits are visible with the reduction in concentration of iron and activated microglia in SCI. Magnetic field attenuates oxidative stress and promotes axonal regeneration in vitro and in vivo. The present study demonstrates the potential of extremely low frequency magnetic field to attenuate microglia- and iron-induced secondary injury in SCI rats. Complete transection of the spinal cord (T13 level) was performed in male Wistar rats and subsequently exposed to magnetic field (50 Hz,17.96 µT) for 2 h daily for 8 weeks. At the end of the study period, spinal cords were dissected to quantify microglia, macrophage, iron content and study the architecture of lesion site. A significant improvement in locomotion was observed in rats of the SCI + MF group as compared to those in the SCI group. Histology, immunohistochemistry and flow cytometry revealed significant reduction in lesion volume, microglia, macrophage, collagen tissue and iron content, whereas, a significantly higher vascular endothelial growth factor expression around the epicenter of the lesion in SCI + MF group as compared to SCI group. These novel findings suggest that exposure to ELF-MF reduces lesion volume, inflammation and iron content in addition to facilitation of angiogenesis following SCI.
脊髓损伤（SCI）是指脊髓受到的损伤，会导致损伤平面以下的感觉和运动功能丧失。SCI会导致即刻的机械性损伤和继发性组织退变。创伤性损伤后，活化的小胶质细胞会释放促炎细胞因子，并且由于出血导致铁过量，引发氧化应激，进而导致继发性退变。文献表明，降低SCI中铁和活化小胶质细胞的浓度会带来益处。磁场在体外和体内均能减轻氧化应激并促进轴突再生。本研究证明了极低频磁场减轻SCI大鼠中小胶质细胞和铁诱导的继发性损伤的潜力。对雄性Wistar大鼠进行脊髓完全横断（T13水平），随后每天暴露于磁场（50Hz，17.96µT）2小时，持续8周。在研究期结束时，解剖脊髓以量化小胶质细胞、巨噬细胞、铁含量，并研究损伤部位的结构。与SCI组相比，SCI + MF组大鼠的运动能力有显著改善。组织学、免疫组织化学和流式细胞术显示，损伤体积、小胶质细胞、巨噬细胞、胶原组织和铁含量显著降低，而与SCI组相比，SCI + MF组损伤中心周围的血管内皮生长因子表达显著更高。这些新发现表明，暴露于极低频磁场除了能促进SCI后的血管生成外，还能减少损伤体积、炎症和铁含量。
