Low-level laser facilitates alternatively activated macrophage/microglia polarization and promotes functional recovery after crush spinal cord injury in rats

• Published in: Scientific reports Vol. 7; no. 1; p. 620
• Main Authors: Song, Ji Wei, Li, Kun, Liang, Zhuo Wen, Dai, Chen, Shen, Xue Feng, Gong, Yu Ze, Wang, Shuang, Hu, Xue Yu, Wang, Zhe
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04-04-2017; Nature Portfolio
• Subjects: 13/1; 13/21; 13/51; 14/63; 631/378/1687/1825; 631/378/87; Animals; Astrocytes - metabolism; Behavior, Animal; Biomarkers; Cytokines - metabolism; Disease Models, Animal; Humanities and Social Sciences; Inflammation Mediators - metabolism; Laser Therapy - methods; Macrophage Activation - immunology; Macrophages - immunology; Macrophages - metabolism; Microglia - metabolism; multidisciplinary; Neurons - metabolism; Neuroprotection; Phenotype; Rats; Recovery of Function - radiation effects; Science; Science (multidisciplinary); Spinal Cord Injuries - etiology; Spinal Cord Injuries - metabolism; Spinal Cord Injuries - rehabilitation; Spinal Cord Injuries - therapy
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-00553-6

Macrophages and resident microglia play an import role in the secondary neuroinflammation response following spinal cord injury. Reprogramming of macrophage/microglia polarization is an import strategy for spinal cord injury restoration. Low-level laser therapy (LLLT) is a noninvasive treatment that has been widely used in neurotrauma and neurodegenerative diseases. However, the influence of low-level laser on polarization of macrophage/microglia following spinal cord injury remains unknown. The present study applied low-level laser therapy on a crush spinal cord injury rat model. Using immunofluorescence, flow cytometry, RT-qPCR, and western blot assays, we found that low-level laser therapy altered the polarization state to a M2 tendency. A greater number of neurons survived in the pare injury site, which was accompanied by higher BBB scores in the LLLT group. Furthermore, low-level laser therapy elevated expression of interleukin 4 (IL-4) and interleukin 13 (IL-13). Results from this study show that low-level laser therapy has the potential for reducing inflammation, regulating macrophage/microglia polarization, and promoting neuronal survival. These beneficial effects demonstrate that low-level laser therapy may be an effective candidate for clinical treatment of spinal cord injury.