Hiroshima K, Maeda T, Hanada K, Wakisaka S
Department of Oral Anatomy, Niigata University School of Dentistry, 2-5274, Gakkocho-dori, Niigata 951-8514, Japan.
Brain Res. 1998 Oct 5;807(1-2):218-21. doi: 10.1016/s0006-8993(98)00799-9.
Regeneration of calretinin (CR)-like immunoreactive (IR) nerve fibers was investigated in the periodontal ligament of the rat lower incisor following resection of the inferior alveolar nerve (IAN). In addition, the degeneration and regeneration processes of periodontal nerve fibers were examined by immunohistochemistry for protein gene product 9.5 (PGP 9.5), a general neuronal marker. In normal animals, the periodontal nerve fibers showing PGP 9.5-like immunoreactivity (LI) formed either periodontal Ruffini endings with expanded arborization and thin free nerve endings in the alveolar half of the ligament. Thick CR-IR nerve fibers also appeared in a dendritic fashion in the same region, but thin CR-IR nerve fibers were rarely observed. Five days following resection of the IAN, a major population of PGP 9.5-IR and all CR-IR nerve fibers disappeared except for some thin PGP 9.5-IR nerves in the periodontal ligament. Regenerated PGP 9.5-IR nerve fibers appeared around 7 days following resection, in contrast to a very small number of regenerated CR-IR nerve fibers. Around 14-21 days following resection, the number and terminal morphology of regenerated PGP 9.5-IR nerve fibers were comparable to those observed in normal animals, but the number of regenerated CR-IR nerve fibers was still smaller than that of normal animals. The number of regenerated CR-IR nerve fibers increased to return to normal by 56 days following injury. The delay of expression of CR-LI in the regenerated periodontal Ruffini endings suggests that functional recovery of periodontal Ruffini endings occurred after the completion of the regeneration of periodontal nerve fibers.
在大鼠下切牙牙周膜中，研究了切断下牙槽神经（IAN）后钙视网膜蛋白（CR）样免疫反应性（IR）神经纤维的再生情况。此外，通过免疫组织化学检测一般神经元标志物蛋白基因产物9.5（PGP 9.5），来检查牙周神经纤维的变性和再生过程。在正常动物中，显示PGP 9.5样免疫反应性（LI）的牙周神经纤维在韧带牙槽侧形成了具有扩张分支的牙周鲁菲尼终末和细的游离神经末梢。粗大的CR-IR神经纤维也以树突状出现在同一区域，但很少观察到细的CR-IR神经纤维。切断IAN 5天后，除了牙周膜中一些细的PGP 9.5-IR神经外，大部分PGP 9.5-IR和所有CR-IR神经纤维消失。与极少量再生的CR-IR神经纤维相反，切断后约7天出现再生的PGP 9.5-IR神经纤维。切断后约14-21天，再生的PGP 9.5-IR神经纤维的数量和终末形态与正常动物中观察到的相当，但再生的CR-IR神经纤维的数量仍低于正常动物。再生的CR-IR神经纤维数量在损伤后56天增加至恢复正常。再生的牙周鲁菲尼终末中CR-LI表达的延迟表明，牙周鲁菲尼终末的功能恢复发生在牙周神经纤维再生完成之后。
