Effects Of ASMase Inhibitor On Radiation Injury And Neurogenesis In Mice

Objective: Establishing a experimental model of acute IR induced impairment of brain neurogenesis in mature BALB/c mice,detect the expression of gene SMPD1 and neurons(DCX、Ki67、PV、CB)in hippocampus after giving ASMase inhibitor,in order to explore effects of ASMase inhibitors on neurogenesis in the brain.Methods: 80 BALB/c mice aged 8 weeks were recruited,and randomly assigned to four groups(n = 20 in each group).The three experimental groups were respectively treated with acute whole-body irradiation with 5 Gy,5 Gy with pre-irradiation 7 days amitriptyline intraperitoneal injection,5 Gy with post-irradiation 14 days amitriptyline intraperitoneal injection.The control group was not irradiated.One day after irradiation,each mouse was tested for weight test for 6 weeks.After the weight test,half part of each groups were for Real-time RT-PCR with hippocampus to detect the expression of gene SMPD1.The other part was euthanized,perfused with saline and 4% formaldehyde,and then the brain was peeled,postfixed in 4% formaldehyde for 24 hours,and finally kept in 30% sucrose.Brain sections were collected with cryostat microtome after the completion of dehydration,then immunostaining for different markers containing DCX,Ki67,PV and CB.Ultimately,positive cells were counted and compared among the experimental and control groups.Results:(1)Significant changes were observed in weight test among four groups of mice after irradiation within 6 weeks(P < 0.01).The weight of control group showed a trend of growth.Compared with the control group,the experimental groups all showed the growth trend after the first decline,and the groups with drugs had improved.(2)There were significant changes in Real-time RT-PCR(P < 0.05).Thereinto,compared with the control group,the expression of gene SMPD1 of experimental groups all had increased,while the groups with drugs had decreased in comparison to 5 Gy acute irradiation group.(3)DCX,Ki67,PV and CB labeled cells in SGZ with immunohistochemical staining indicated significant differences among four groups(P < 0.05).Compared to control group,the three irradiation groups all showed decreased number of labeled cells.And 5 Gy acute irradiation group showed the lowest number,the two groups with drugs are higher.Conclusion:(1)5 Gy acute irradiation and ASMase inhibitor at four groups of mature mice resulted in observed changes in the body weight.(2)5 Gy acute irradiation and ASMase inhibitor in BALB/c mature mice induced difference in the expression of gene SMPD1.(3)5 Gy dose irradiation induced impairment of neurogenesis in mice,and giving ASMase inhibitor can relieve the damage effect of neurogenesis.(4)The acute radiation induced lesions of neurogenesis included a series of biological processes,including proliferation,migration,differentiation and maturation of neurons.(5)ASMase inhibitors can provide a new target for the development of anti-radiation drugs and improvement of neurogenesis.