The Influence Of The Low-level Laser On Polarization Of Bone Marrowderived Macrophage And Rat Spinal Cord Injory

Spinal cord injury(SCI) always cause permanent disabilities in patients and give the family and society a heavy burden. A series of pathological changes after spinal cord injury including inflammatory responses, lipid peroxidation, Glutamate excitability toxicity, local vascular disorders, demyelinating that make the patients’ conditions complicated. Macrophagocytes, a determine factor of the internal environment of SCI, play an important role in the process of inflammation which is one of the main pathological processes post-SCI. Macrophagocytes activated and transformed to M1 and M2 cells post-SCI, M1 cells generate toxic effect against neurons and spongiocytes through the pro-inflammatory cytokines secreting including IL-1β, IL-6 and TNF-α. However, M2 cells secrete anti-inflammatory cytokines such as IL-10 and TGF-B and reduce the damage to the live cells. The prognosis of SCI may influenced by different inflammatory situations.Low-level laser has been widely used in the area of cosmetology and acupuncture therapy due to its better biological contact effect and the character of safety and stability. Moreover, the therapeutic effect of weak laser has been reported for its anti-inflammatory effect by the expression of TNF-α, IL-6 and IL-10 in the early stage of SCI.Our present study focused on the local inflammatory responses and investigated the influence of laser of different energy on the M1 and M2 cells in order to find new therapeutic strategy for SCIFirstly,To test the LPS-induced polarization and the expression of specific genes of bone marrow macrophage derived from Balb/c-WT mouse by flow cytometry and qPCR/Western blot respectively. To observe the cell viability and the polarization of M1 cells induced by 810 nm low-level laser of different energy by the detection of immunofluorescent staining, MTT、qPCR and Western blotSecondly,BBB score and foot imprinting experiments were performed days after the model establishment to observe the motion recovery condition of rats.We get these results from the experiment,By the test of flow cytometry, we found that the positive rate of F4/80 of the cells cultured with M-CSF conditioned medium was 98%. The expression of the mRNA and the protein level of both iNOS and CD86 of the macrophage cells were significantly higher when induced by LPS-INF-γ. The viability of M1 cells was significantly decreased when the energy of the low-level laser was 4J/cm2 while the viability remains unchanged when induced by the energy of 1, 2 or 3J/cm2 compared with the control group. Differences in the content of the Arg1 positive cells that represent the M2 cells were not significant between groups when the irradiation doses were 1 or 2J/cm-2 by the detection of immunocytochemistry, however, the Arg1 positives cells were significantly increased and the iNOS positive cells that represent M1 cells were significantly increased when the irradiation doses were 3 or 4 J/cm2. The mRNA and protein expression of iNOS and Arg1 remain unchanged compared with the control group when the irradiation doses were 1 or 2J/cm2. When the irradiation doses were 3 or 4 J/cm2, the expression of mRNA and protein of iNOS(the biomarker of the M1 cells) significantly decreased and the expression of Arg1(the biomarker of the M2 cells) significantly increased.BBB score and foot imprinting experiments showed that there’s no significant difference in the motor function of irradiating power of 1 or 2J/cm-2compared with the control group while when the irradiating power raise to 3 or 4 J/cm2, the motor function recovered and promote the motor function recovery of rats.810nm low-level lasers with the energy of 1 or 2 J/cm2 have no significant impact on the polarization and viability of macrophage cells. M1 cells can be polarized into M2 cells while there was no significant difference in the cell viability when the energy was 3J/cm2. When the energy was 4 J/cm2, M1 cells polarized into M2 cells and the cell viability significantly decreased.1 or 2 J/cm2 have no significant impact on the population and viability of macrophage cells, 3 or 4 J/cm2 decrease the population of M1 and increase M2 in the injury area, the motor function recovered and promote the motor function recovery of rats.