Department of Otolaryngology-Head and Neck Surgery, University of Iowa, IA 52242, USA.
Neuroscience. 2011 Mar 17;177:321-34. doi: 10.1016/j.neuroscience.2011.01.014. Epub 2011 Jan 14.
Spiral ganglion neurons (SGNs) extend processes that interact with Schwann cells (SCs) and with oligodendrocytes (OLs) and astrocytes (ACs). We investigated the ability of these glial cells to support SGN neurite growth. In the presence of cultured ACs, OLs and SCs, SGN neurites tended to follow SCs and OLs and cross-over ACs. Most neurites initially followed the type of glial cell on which the neuronal cell body was found. To determine the influence of homogeneous populations of glia on neurite growth, SG explants were plated on cultured SCs, ACs or OLs. The number of neurites/explant extending onto SCs (463.89±16.25) was significantly greater than the number extending onto ACs (111.38±38.73) or OLs (6.75±2.21), indicating that populations of central glia inhibit SGN neurite growth. Treatment with cell-permeant cpt-cAMP or forskolin (FSK) each significantly increased the number of neurites on OLs (133.54±25.59 and 292.25±83.57, respectively). cpt-cAMP and FSK each also increased the number of neurites on ACs (213.19±36.06 and 208.64±59.25, respectively), however the difference was not significant compared with control. The neurites on ACs and OLs failed to grow radially in a well-fasciculated pattern as on SCs. In explants plated on the borders of cultured OL-SC or AC-SC groups, more neurites extended onto SCs compared with OLs and ACs. Conditioned media (CM) from OL or AC cultures did not reduce neurite length, implying that the inhibition of neurite growth by central glia is not due to soluble factors. Taken together, these results demonstrate that homogeneous populations of central glia inhibit SGN neurite growth.
螺旋神经节神经元 (SGNs) 延伸出与施旺细胞 (SCs)、少突胶质细胞 (OLs) 和星形胶质细胞 (ACs) 相互作用的突起。我们研究了这些神经胶质细胞支持 SGN 神经突生长的能力。在存在培养的 ACs、OLs 和 SCs 的情况下，SGN 神经突倾向于沿着 SCs 和 OLs 生长，并跨越 ACs。大多数神经突最初沿着神经元胞体所在的神经胶质细胞的类型生长。为了确定同质神经胶质细胞群体对神经突生长的影响，将 SG 外植体接种在培养的 SCs、ACs 或 OLs 上。在 SCs 上延伸的神经突/外植体数量（463.89±16.25）明显大于在 ACs（111.38±38.73）或 OLs（6.75±2.21）上延伸的数量，表明中枢神经胶质细胞群体抑制 SGN 神经突生长。细胞通透的 cpt-cAMP 或 forskolin (FSK) 处理均显著增加 OL 上的神经突数量（分别为 133.54±25.59 和 292.25±83.57）。cpt-cAMP 和 FSK 处理也分别增加了 AC 上的神经突数量（分别为 213.19±36.06 和 208.64±59.25），但与对照组相比差异无统计学意义。AC 和 OL 上的神经突未能像 SC 上那样呈辐射状生长成良好的束状模式。在外植体接种在培养的 OL-SC 或 AC-SC 组边界上，与 OL 和 AC 相比，更多的神经突延伸到 SC 上。来自 OL 或 AC 培养物的条件培养基 (CM) 并未减少神经突长度，这表明中枢神经胶质细胞对神经突生长的抑制不是由于可溶性因子。综上所述，这些结果表明，同质中枢神经胶质细胞群体抑制 SGN 神经突生长。
