Division of Orofacial Functions and Orthodontics, Kyushu Dental University.
Acta Histochem Cytochem. 2013 Apr 30;46(2):65-73. doi: 10.1267/ahc.13003. Epub 2013 Apr 12.
Nerve growth factor (NGF) plays a critical role in the trigeminal ganglion (TG) following peripheral nerve damage in the oral region. Although neurons in the TG are surrounded by satellite glial cells (SGCs) that passively support neural function, little is known regarding NGF expression and its interactions with TG neurons and SGCs. This study was performed to examine the expression of NGF in TG neurons and SGCs with nerve damage by experimental tooth movement. An elastic band was inserted between the first and second upper molars of rats. The TG was removed at 0-7 days after tooth movement. Using in situ hybridization, NGF mRNA was expressed in both neurons and SGCs. Immunostaining for NGF demonstrated that during tooth movement the number of NGF-immunoreactive SGCs increased significantly as compared with baseline and reached maximum levels at day 3. Furthermore, the administration of the gap junction inhibitor carbenoxolone at the TG during tooth movement significantly decreased the number of NGF-immunoreactive SGCs. These results suggested that peripheral nerve damage may induce signal transduction from neurons to SGCs via gap junctions, inducing NGF expression in SGCs around neurons, and released NGF may be involved in the restoration of damaged neurons.
神经生长因子（NGF）在外周神经损伤后在三叉神经节（TG）中发挥关键作用。尽管 TG 中的神经元被卫星神经胶质细胞（SGCs）包围，这些 SGCs被动地支持神经功能，但对于 NGF 的表达及其与 TG 神经元和 SGCs 的相互作用知之甚少。本研究通过实验性牙齿移动来检查 NGF 在 TG 神经元和 SGCs 中的表达。在大鼠的第一和第二上颌磨牙之间插入弹性带。在牙齿移动后 0-7 天取出 TG。通过原位杂交，在神经元和 SGCs 中均表达 NGF mRNA。NGF 的免疫染色显示，在牙齿移动过程中，与基线相比，NGF-免疫反应性 SGCs 的数量显著增加，并在第 3 天达到最大值。此外，在牙齿移动期间向 TG 施用缝隙连接抑制剂 carbenoxolone 可显著减少 NGF-免疫反应性 SGCs 的数量。这些结果表明，外周神经损伤可能通过缝隙连接诱导来自神经元的信号转导，诱导神经元周围 SGCs 中 NGF 的表达，释放的 NGF 可能参与受损神经元的修复。
