Atsumi Y, Imai T, Matsumoto K, Sakuda M, Maeda T, Kurisu K, Wakisaka S
Department of Oral Anatomy and Developmental Biology, Osaka University Faculty of Dentistry, Suita, Japan.
Arch Histol Cytol. 2000 Mar;63(1):43-54. doi: 10.1679/aohc.63.43.
The present study reports on different regeneration patterns of axons and Schwann cells in the periodontal ligament of the rat incisor using immunohistochemistry of protein gene product 9.5 (PGP 9.5) and S-100 protein. Three kinds of injury (transection, crush and segmental resection) were applied to the inferior alveolar nerve. In normal animals, PGP 9.5- and S-100-immunoreactivities were detected in the axons and Schwann cell elements of periodontal Ruffini endings, respectively. They were restricted to the alveolus-related part, occurring only rarely in the tooth-related part and in the shear zone (the border between the alveolus-related and tooth-related parts). Both transection and segmental resection caused the complete disappearance of PGP 9.5-immunoreactive nerve fibers in the periodontal ligament, while a small number of them could be found following the crush injury. Regenerating PGP 9.5-reactive nerve fibers appeared at 5 days and 21 days following the transection and segmental resection, respectively. The regeneration of periodontal nerve fibers completed in a period of 21-28 days and 14-21 days following the transection and crush, respectively, but was not completed even at 56 days following the segmental resection. The behavior of Schwann cells during regeneration was similar after the different nerve injuries; spindle-shaped S-100-immunoreactive cells, presumably Schwann cells, appeared in the shear zone and the tooth-related part. These cells disappeared 5-7 days prior to the completion of the regeneration of axonal elements of the periodontal ligament following the transection and crush. Following the segmental resection, in contrast, spindle-shaped S-100-positive cells disappeared from the tooth-related part at 42 days, although the axonal regeneration of periodontal Ruffini endings proceeded even until 56 days. We thus conclude that the duration of the migration of Schwann cells depends on the state of the regeneration of axons.
本研究利用蛋白质基因产物9.5（PGP 9.5）和S-100蛋白的免疫组织化学方法，报道了大鼠切牙牙周膜中轴突和施万细胞的不同再生模式。对下牙槽神经施加了三种损伤（横断、挤压和节段性切除）。在正常动物中，分别在牙周鲁菲尼末梢的轴突和施万细胞成分中检测到PGP 9.5和S-100免疫反应性。它们局限于牙槽相关部分，在牙齿相关部分和剪切区（牙槽相关部分与牙齿相关部分之间的边界）中很少出现。横断和节段性切除均导致牙周膜中PGP 9.5免疫反应性神经纤维完全消失，而挤压伤后可发现少量此类神经纤维。横断和节段性切除后，分别在第5天和第21天出现再生的PGP 9.5反应性神经纤维。牙周神经纤维的再生分别在横断和挤压后21 - 28天和14 - 21天完成，但节段性切除后即使在56天时仍未完成。不同神经损伤后施万细胞在再生过程中的行为相似；纺锤形的S-100免疫反应性细胞，可能是施万细胞，出现在剪切区和牙齿相关部分。这些细胞在横断和挤压后牙周膜轴突成分再生完成前5 - 7天消失。相比之下，节段性切除后，尽管牙周鲁菲尼末梢的轴突再生一直持续到56天，但纺锤形的S-100阳性细胞在42天时从牙齿相关部分消失。因此，我们得出结论，施万细胞迁移的持续时间取决于轴突再生的状态。
