BMSC-CM Reduces The Effects Of Oxidative Stress Damage On Neural Stem Cells By Inhibiting Notch1 Signaling Pathway

BACKGROUND: Spinal cord injury(SCI)is common in industrial and agricultural production,often lead to severe neurological disorders and paralysis,creating a huge burden to individual families and society.Previous studies have indicated that SCI could be divided into two categories: primary damage and secondary damage.Excessive inflammatory responses can exacerbate oxidative stress injury and lead to numerous neural cell deaths.It has been demonstrated that the transplantation of stem cells can generate large numbers of neurons and oligodendrocytes.Stem cells(SCs)are a class of cells that can not only reproduce themselves but also have the potential to differentiate into multiple tissues.Previous studies have demonstrated that NSCs have the potential to differentiate into neurons that can contribute to the repair of spinal cord tissue after injury.However,it is difficult for them to survive because of the oxidative stress environment after spinal cord injury.Therefore,reducing oxidative stress injury becomes the vital process of NSCs to treat SCI.The current study suggests that the Noth1 signaling pathway is an important signaling pathway in biological evolution and plays an important role in cell growth,differentiation,migration and death.Studies have shown that under the oxidative stress Notch1 signaling pathway has been increased,cell death increased,suggesting that inhibition of Notch1 signaling pathway may increase cell survival in oxidative stress environment.OBJECTIVE: This study aimed to investigate the protective effect of BMSC-CM on oxidative stress-induced injury of neural stem cells(NSCs)induced by hydrogen peroxide(H2O2)and the role of Notch1 signaling pathway.Methods: Bone marrow mesenchymal stem cells were obtained from the femoral shaft of SD rats.The mesenchymal stem cell conditioned medium(BMSC-CM)was obtained from the third passage.Fresh brain tissue was harvested from neonatal rats(24 h)and neural stem cells were used after culturing for seven days in culture medium.The apoptosis rate of each group was detected by flow cytometry using their own special kit detection.Lactate dehydrogenase(LDH),malondialdehyde(MDA)and superoxide dismutase(SOD)activity were evaluated via corresponding assay kits.The western blot was used to detect the expressions of Notch1,HES1,Caspase-3,cleave Caspase-3,Bax and Bcl-2.Results: We found that H2O2 could significantly induce the apoptosis of NSCs,increase LDH,MDA levels and decrease SOD activity by activating the Notch1 signaling pathway.DAPT(the specific blocker of Notch1)and BMSC-CM could significantly prevent the apoptotic effect and oxidative stress injury on NSCs that were treated with H2O2.We also revealed that the BMSC-CM could decrease the expression of Notch1,Hes1,cleave Caspase-3,Bax and increases the expression of Bcl-2 in NSCs which was induced by H2O2.CONCLUSION: These results indicate that inhibition of Notch1 signaling pathway could attenuate oxidative stress-induced injury of neural stem cells,and that BMSC-CM could neutralize the effects of oxidative stress on apoptosis of NSCs by inhibiting Notch1 signaling pathway.