| Objective:To explore the effects of stromal cell-derived factor-1(SDF-1) on migration of neural stem cell (NSCs), and its possible mechanism, provide the theory basis of the central nervous system diseases treatment.Methods:The fetal rat hippocampal neural stem cells were isolated, cultured and identified in serum-free medium. To detect the expression of CXCR4 in neural stem cells using immunofluorescence and RT-PCR. Using The Under-Agarose cell migration assay to observe the effects of SDF-1(50-500ng/ml) on neural stem cell migration, and blocking CXCR4, the receptor of SDF-1, to identify the specificity of migration; Using Feeney's and other's method,self-made free-fall drop device hit rats left motor and somatoserisory cortex to made traumatic brian injury in adult rats. After 3d,5d,7d the brain was taken, though frozen section immunohistochemical, by professional image analysis software Image-Pro Plus6.0, analysis the relationship between SDF-1 and endogenous neural stem cell proliferation and migration after traumatic brian injury in adult rats.Results:The cell isolated and cultured from fetal rats hippocampus suspension growth, about 1 week composed spherical group. After passage the cell proliferation exuberant, fourth-generation cells expression of NF200, Nestin, GFAP,CNP and CXCR4 was positive by immunofluorescence. RT-PCR shown 643bp specific band in agarose gel electrophoresis. SDF-1 (50-500ng/ml) could accelerated the migration of neural stem cells, and the migration increased with the concentration. By adding anti-CXCR4 polyclonal antibodies the migration of neural stem cells compared with SDF-1 was significantly reduced, no significant difference with the control group(P>0.05). All adult rats after injury, present limbs buckling, breathing deep and fast, pulse quickly, blood pressure sharply after sag, and even death. About 3 hour the rats awake, but the right lower limbs movement obviously disorder, most rotate circle movement to hemiplegia side, then recovery. While the control group action normal. Brain injured rats compared control group the nerve ethology score was significantly difference. Frozen section immunohistochemical shown:injured 3d,the SDF-1 expression rised clear than control group, the hippocampus area visible large obviously Nestin positive cells, but no migration to damaged area; then 5d,SDF-1 express more apparent, only few Nestin positive cell to the damaged area, and after 7d, SDF-1 expression expanding, while in damaged area appear Nestin positive cells. The control group haven't these change.Conclusion:The cell isolated from fetal rats hippocampus organization have the ability of self-renewal and differentiation, identified as neural stem cells, its expression chemotactic factors receptors-CXCR4. The Under-Agarose cell migration assay showed that SDF-1 could accelerated the migration of neural stem cells, and the migration increased with the concentration,500ng/ml is the best. By adding anti-CXCR4 polyclonal antibodies the migration of neural stem cells compared with SDF-1 was significantly reduced, no significant difference with the control group(P >0.05), point out SDF-1 must combined with its receptor CXCR4-1 play a role; After traumatic brian injury in adult rats the SDF-1 express glaringly over time, and endogenous neural stem cells are activation,proliferation, and migration to the damaged area after injured,7 days arrived damaged area, this indicating that the SDF-1 participation endogenous neural stem cell proliferation and the process of migration to the damaged area.
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