Rabchevsky A G, Streit W J
Department of Neuroscience, University of Florida College of Medicine, Gainesville 32610, USA.
J Neurosci Res. 1997 Jan 1;47(1):34-48.
There is contrasting in vitro and in vivo evidence regarding glial cell involvement in central nervous system (CNS) regeneration. This study has investigated the histological events that follow implantation of either microglia, mixed microglia/astrocytes, or astrocytes into the injured adult rat spinal cord. We have conducted an immunohistochemical characterization of the cellular profiles within and neuritic extension into various grafts consisting of gelfoam (GF) matrices impregnated with cultured microglia and/or astrocytes. After 2-5 weeks, prominent neuritic growth was observed into OX-42-immunoreactive (IR) microglial implants. These grafts were infiltrated by numerous host cellular elements including microvasculature and Schwann cells, and they demonstrated conspicuous laminin IR. Often, the patterns for laminin and OX-42 IR in microglial grafts were overlapping, suggesting partial expression of laminin on transplanted microglial cells. Mixed grafts of microglia and astrocytes demonstrated presence of neurites and laminin-IR elements with similar intensity as microglial grafts, while astroglial implants showed the least amount of neurite ingrowth. Some control implants consisting of cell-free GF showed marginal in-growth of neurites in areas of infiltrating OX-42-IR host cells. Collectively, our findings support a neurite growth-promoting role of activated microglia and suggest that microglia may counteract mechanisms that inhibit CNS regeneration. It remains to be determined whether the observed neurite growth-promoting effects are mediated directly by grafted and/or endogenous microglia, or whether this occurs via the recruitment of host Schwann cells.
关于神经胶质细胞参与中枢神经系统（CNS）再生，体外和体内证据存在差异。本研究调查了将小胶质细胞、混合小胶质细胞/星形胶质细胞或星形胶质细胞植入成年大鼠受伤脊髓后发生的组织学事件。我们对各种移植物内的细胞形态以及神经突向由含有培养的小胶质细胞和/或星形胶质细胞的明胶海绵（GF）基质组成的移植物的延伸进行了免疫组织化学表征。2至5周后，观察到神经突显著生长进入OX - 42免疫反应性（IR）小胶质细胞移植物。这些移植物被包括微血管和施万细胞在内的众多宿主细胞成分浸润，并且它们显示出明显的层粘连蛋白IR。通常，小胶质细胞移植物中层粘连蛋白和OX - 42 IR的模式重叠，表明层粘连蛋白在移植的小胶质细胞上部分表达。小胶质细胞和星形胶质细胞的混合移植物显示出神经突和层粘连蛋白 - IR成分的存在，其强度与小胶质细胞移植物相似，而星形胶质细胞移植物显示出最少的神经突向内生长。一些由无细胞GF组成的对照移植物在浸润OX - 42 - IR宿主细胞的区域显示出神经突的边缘向内生长。总体而言，我们的研究结果支持活化的小胶质细胞具有促进神经突生长的作用，并表明小胶质细胞可能抵消抑制CNS再生的机制。观察到的神经突生长促进作用是直接由移植的和/或内源性小胶质细胞介导，还是通过招募宿主施万细胞发生，仍有待确定。
