Effect Of Calcium-binding Protein S100A4 And S100B On Adult Rats Dentate Gyrus Neural Stem Cells Proliferation And Differentiation Under Highland Environment

Objective:To observe the effect of rat dentate gyrus neurogenesis under Altitude hypobaric hypoxia environment,to explore the mechanism of neurogenesis and neural function repair after Hypobaric hypoxia brain injury.To provide the experimental basis for the clinical treatment of central nervous system injury and degenerative diseases of the nervous system. Methods:120 healthy adult male SD rats were randomly divided into two groups: group simulated altitude of 5000 meters, atmospheric pressure 52.9 k Pa(experimental group) and an altitude of 2200 meters group,atmospheric pressure 77.406 k Pa(control group). Experimental group is pretreatment 3 days in the simulated altitude 5000 m hypobaric chamber,hypobaric hypoxia 3 days into the repair period,then shift to altitude 2200 meters environment.Control group was reared under 2200 meters altitude environment,without a simulated altitude of 5000 m in a hypobaric chamber pretreatment. Two group divided into five subgroup after hypoxia injury:1 day, 3 days, 7 days, 14 days, and 28 days, respectively, n=12.To observe changes of brain tissue morphology after hypobaric hypoxia brain injury respectively by H-E staining, Nissl staining to detect the expression of Brd U-positive cells by using Brd U labeling, and Brd U immunohistochemistry to observe changes of neural stem cell proliferation after Hypobaric hypoxia brain injury,to observe the ability on differentiation of neural stem cells by double immunofluorescence detection of Brd U and DCX, GFAP co-expression,to detect distribution and number of changes of calcium-binding protein family S100 B, S100A4-positive cells;to detect the expression of S100 B, S100A4 by using q RT-PCR technology.Results:(1)HE staining results:compared with control group,the experimental group after hypoxic injury 1-3 days, hippocampal granule cell damage significantly, appear irregular or heterosexual cell vacuolization of cells and apoptotic cells appear nuclear enrichment;Nissl staining results:compared with control group, 1day,3days, 7days in the experimental gruop rats hippocampus degeneration/necrosis cells was significantly increased(p <0.05), to observed cell degeneration and derangement by Nissl stain.(2)Brd U immunohistochemistry results : the experimental group Brd U-positive cells after hypoxia injury in 7days, 14 days, 28 days after hypoxia injury significantly higher than the corresponding time points(p<0.05).(3)Brd U/DCX and Brd U/GFAP double immunofluorescence results :under high altitude environment,the expression of DCX-positive cells and GFAP on hippocampus dentate gyrus, after hypoxic injury.(4)S100B immunohistochemistry results:the expression of S100 B protein in experimental group after hypobaric hypoxia injury was significantly higher than control group in 1day and 3days of the corresponding point in time(p <0.05),other time points S100 B protein expression was no significant difference,the expression of S100 B protein and degree of hippocampal damage on organizational structure are consistent.(5)S100B immunohistochemistry results:the experimental group S100A4-positive cells after hypoxia injury in 7days, 14 days, 28 days after hypoxia injury significantly higher than the corresponding time points(p< 0.05), and the time point of Neural stem cells proliferation are basically consistent. The expression of 28 days group showed no significant difference.(6)To detect S100 B, S100A4 gene expression by q RT-PCR technology, the results showed that the experimental group S100A4 gene in hypoxic injury after 3 days, 7 days, 14 days was significantly higher than the control group(p< 0.05),experimental group S100 B gene hypoxic injury after 1 day, 3 days group was significantly higher(p< 0.05). Conclusion: 1.High altitude hypoxia stimulation activated neural stem cell proliferation in rat hippocampal dentate gyrus subgranular zone. 2.After hypobaric hypoxia brain injury,Proliferation of neural stem cells in hippocampal dentate gyrus can differentiate into neurons or glial cells. 3.High altitude hypoxia stimulation can induce calcium-binding protein family S100 B and S100A4 protein upregulated, overexpression of S100 B is involved in the induction of hippocampal cell damage or apoptosis by activating certain signaling pathways,however, high expression of calcium-binding protein S100A4 may be involved in the process on proliferation and differentiation of neural stem cells.