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目的:研究骨形态发生蛋白4(bone morphogenetic protein4,BMP-4)在视网膜与视神经上的表达情况及其对少突胶质前体细胞(oligodendrocyte precursor cells,OPCs)分化的影响,进一步探讨视神经乳头处无髓鞘形成的原因。方法:取生后7d SD大鼠视神经,用免疫组织化学方法研究BMP-4的表达情况。采用恒温振荡法和差速贴壁法分离纯化新生SD大鼠OPCs。用BMP-4诱导OPCs分化,通过免疫细胞化学方法研究OPCs的分化方向。通过Western Blot方法研究BMP-4浓度与OPCs细胞体系内Olig2蛋白表达水平之间的相互关系。结果:(1)在发育过程中,BMP-4仅选择性表达在视神经乳头处;(2)成功纯化的OPCs在PDGF和bFGF撤除后自发分化为少突胶质细胞;(3)OPCs经BMP-4诱导后向II型星形胶质细胞分化;(4)OPCs内Olig2蛋白的表达量随着BMP-4浓度的逐渐增高而逐渐降低。结论:在视神经乳头表达的BMP-4蛋白有可能作用于迁移至此处的OPCs,通过激活相关信号途径以下调OPCs内Olig2蛋白的表达水平,抑制OPCs向少突胶质细胞方向分化,从而抑制视神经乳头髓鞘形成。
OBJECTIVE: To study the expression of bone morphogenetic protein 4 (BMP-4) on the retina and optic nerve and its effect on the differentiation of oligodendrocyte precursor cells (OPCs). To further explore the effect of optic nerve head Department of non-myelinated reasons. Methods: The optic nerve of Sprague Dawley (SD) rats was taken for 7 days and the expression of BMP-4 was studied by immunohistochemistry. The newborn SD rats OPCs were isolated and purified by constant temperature shaking method and differential adherence method. The differentiation of OPCs was induced by BMP-4 and the differentiation direction of OPCs was studied by immunocytochemistry. Western Blot method was used to study the relationship between BMP-4 concentration and Olig2 protein expression in OPCs cell system. RESULTS: (1) BMP-4 was selectively expressed only in the optic nerve head during development; (2) OPCs were successfully purified and differentiated into oligodendrocytes spontaneously after the removal of PDGF and bFGF; (3) -4 induced differentiation to type II astrocytes; (4) Olig2 protein expression in OPCs gradually decreased with the increasing of BMP-4 concentration. CONCLUSION: The expression of BMP-4 protein in the optic nerve head may affect the migration of OPCs to OPCs. OPCs can inhibit the differentiation of OPCs into oligodendrocytes by down-regulating the expression level of Olig2 protein in OPCs and thus inhibit the optic nerve Myelination of the nipple.