Application Of Low Energy Laser In Tissue Repair

Objective:Low level laser therapy (LLLT) can enhance activity of stem cell (SC) proliferation, differentiation and tissue repair, which can be used in the treatment of regenerative medicine. However, the therapeutic mechanism of LLLT is uncertain, which impede its clinical application and development. Therefore, this study will investigate the mechanism of dual-wavelength LLLT in enhancing the vitality of stem cell and its application in the field of spinal cord injury and radioresistance. At the same time, explore the mechanism of LLLT improving fibroblast function, which is damaged under the environment of high glucose in the cellular and molecular level, and explore the application in the research in tissue repair to provide theoretical basis for the clinical treatment and promotion of dual-wavelength laser.Methods:Cultivate hUCMSCs and human fibroblasts in vitro. Use the 635/808 nm dual wavelength semiconductor lasers, according to the dose of 20 mW/cm2、0-24 J/cm2. Detect cell proliferation activity, reactive oxygen species production, antioxidant enzyme (CA、SOD and tGPx) activity, lipid oxidation (MDA)ability, cell growth factors and related protein expression respectively. Treat the rat model of spinal cord injury with LLLT joint hUCMSCs transplantation. Evaluate the rat behavior, histopathological evaluation of spinal cord tissue and tracking spinal nerve fibers by using DTI technology.Results:1. After the 635 nm and dual-wavelength LLLT, hUCMSCs number is significantly greater than that of the control group. LLLT promotes ROS low expression. CAT、SOD and tGPx enzyme activity increased.808 nm LLLT promotes the increasing of MDA. LLLT promotes the production of IL-1、IL- 6 and NFκB significantly, in which the dual-wavelength effect is best.2. LLLT joint hUCMSCs promote nerve recovery of spinal cord injury in rats. The behavior score is higher than that of the control group. NF-200 and GFAP expression increased. Nissl body was dyed darker and quantity more in the experiment groups. DTI results show that the nerve fiber of control group fractured, the fiber bundle of treatment group interlaced. Rats in the LLLT group had the lowest death rate and lowest mortality rate.3. γ ray irradiation treatment has obvious damage to DNA. The comet tail DNA in LLLT joint γ ray group increased more than that in the control group, but reduced compared with the y ray group. Pretreatment with LLLT reduces the oxidative stress level caused by ionizing radiation, and improve the antioxidant enzyme activity.4. LLLT enhances the ability of fibroblast proliferation, and improves the inhibition of cell proliferation by the high glucose environment. LLLT promotes the expression of ROS, improves the antioxidant enzyme activity, stimulates the cells secrete a variety of factors (FGF, NGF, IGF, TGF, IL-1, IL-6, NFκB and VEGF), reduces the expression of MMPs, increase the expression of TIMPs. It reverses the high expression of MMPs/TIMPs caused by high glucose environment, and increases the expression of collagen.Conclusion:Low level oxidative stress reaction induced by LLLT can promote the proliferation of cells, and cell antioxidant enzyme activity, enhance the cell’s resistance to the external environment, reduce the radiation sensitivity, improve the inhibition of cell proliferation in the high glucose environment. LLLT stimulates cells secrete a variety of factors, which regulate the process of wound healing, LLLT joint stem cells promote regeneration of the damaged nerve fiber and function restoration. Red and near-infrared laser stimulation effect on the cell is different. Biological effects of dual wavelength laser joint two wavelengths laser has a better curative effect to stem cell transplantation, spinal cord injury and trauma repair.