Study On Radiation Protection Of Stem Cells Induced By Low Level Laser

Ironizing radiation could induce radiation injury such like increasing reactive oxygen species(ROS),DNA damage,and apoptosis of mitochondria pathway,and brought serious sickness and disaster in radiation accidents.No efficiency drugs or physicotheropeutics had been found as yet.Therefore,it will be meaningful for exploring new methods without toxic and side effects in radiation protection study.Low level laser irradiation(LLLI)was a kind of light that was harmless to biological tissue;LLLI was also used as an important physical therapy.Its application includes wound healing,soft and hard tissue,treating pain syndromes,enthesopathy,peripheral nerve injury,traumatic brain injury and peripheral neuropathy,improving muscular performance.Our study showed LLLI performed function of irradiation protection by photo-modulation,while mechanism of the LLLI in anti-irradiation was not clear.Its function might be initially regulated by ROS increasing with a low level dose,and promoted phosphorylated regulation in activation of PKC regulation,hydrolyzed in keapl-Nrf2 compound protein,released Nrf2 access into nuclear and banded onto antioxidant responsive element(ARE),initiated the transcription of phase II antioxidant enzyme genes,leading an enhanced activity of irradiation protection.Therefore,we discussed the promising prospect of LLLI in radiation protection in three parts.Biological effection of stem cells irradiation of laser,function of Nrf2 pathway in radiation protection induced by LLLI,and molecular mechanism and application in ionizing radiation protection discussed with in vitro experiment.In in vivo part,cell survival ratio,DNA damage assay,ROS level and other ionizing radiation injury indexs were discussed,oxidated stress of LLLI enhanced the radioresisitence by increasing the activity of antioxidant enzyme.In part of molecular mechynism study,we use radio-sensitive tissue hematopoietic stem cells as research object,and employ ROS cleaning regent NAC,Nrf2 RNAi and Nrf2 inhibitor Brusatol(functioned by degradation of Nrf2 protein)in in vitro experiments(Eliasa,Westemblot and SAGE et al.),using C57 mouse with hematopoietic function acute radiation sickness(H-ARS)as injury model in assessment of anti-radiation level in vehicle control,stem cell transplantation and Nrf2 RNAi stem cell transplation mice after LLLI treatment of graft to be treated for in vitro experiments.Cell counting of blood,nucleated cell counting in marrow,bone marrow smear,pathological section and survival time were recorded and anlysised.In group of stem cell transplation using LLLI pretreatment,bone marrow and splenic pathological tissue changes obviously,hematopoietic tissue improved better than other groups.The key pathway in anti-radiation function of LLLI had been assessed through in vitro and in vivo experiments.Proposed the possible pathway ROS-Nrf2-ARE in anti-radiation function of LLLI.Accomplishment of this study might verify the irradiation antioxidant protection of LLLI,provided regulation pathway in theoretical support aspect.It would be not only using for radiation protection and stem cell transplantation,but also in oxidant related disease such as Parkinson.