PMID- 17245704 OWN - NLM STAT- MEDLINE DCOM- 20070320 LR - 20161124 IS - 0021-9967 (Print) IS - 0021-9967 (Linking) VI - 501 IP - 3 DP - 2007 Mar 20 TI - Involvement of neurotrophin-4/5 in regeneration of the periodontal Ruffini endings at the early stage. PG - 400-12 AB - Little is known about the role of neurotrophin-4/5 (NT-4/5) in the regeneration of mechanoreceptors. Therefore, the present study examined the regeneration process of Ruffini endings in the periodontal ligament in nt-4/5-deficient and wildtype mice following transection of the inferior alveolar nerve by immunohistochemistry for protein gene product 9.5 (PGP 9.5), a general neuronal marker, and by computer-assisted quantitative image analysis. Furthermore, rescue experiments by a continuous administration of recombinant NT-4/5 were performed and analyzed quantitatively. At postoperative day 3 (PO 3d), almost all PGP 9.5-positive neural elements had disappeared; they began to appear in both types of animals at PO 7d. At PO 10d, almost all nerve fibers showed a beaded appearance, with fewer ramifications in both types of mice. Although the regeneration proceeded in the wildtype, a major population of the periodontal Ruffini endings continued to display smooth outlines at PO 28d in the nt-4/5 homozygous mice. The reduction ratio of neural density reached a maximum at PO 3d, decreased at PO 10d, and later showed a plateau. In a rescue experiment, an administration of NT-4/5 showed an acceleration of nerve regeneration in the homozygous mice. These findings indicate that the nt-4/5-depletion causes a delay in the regeneration of the periodontal Ruffini endings, but the delay is shortened by an exogenous administration of NT-4/5. Combined with our previous findings of bdnf-deficient mice (Harada et al. [2003] Arch Histol Cytol 66:183-194), these morphological and numerical data suggest that multiple neurotrophins such as NT-4/5 and brain-derived neurotrophic factor (BDNF) play roles in their regeneration in a stage-specific manner. CI - 2007 Wiley-Liss, Inc. FAU - Jabbar, Shahiqul AU - Jabbar S AD - Division of Oral Anatomy, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. FAU - Harada, Fumiko AU - Harada F FAU - Aita, Megumi AU - Aita M FAU - Ohishi, Megumi AU - Ohishi M FAU - Saito, Isao AU - Saito I FAU - Kawano, Yoshiro AU - Kawano Y FAU - Suzuki, Akiko AU - Suzuki A FAU - Nozawa-Inoue, Kayoko AU - Nozawa-Inoue K FAU - Maeda, Takeyasu AU - Maeda T LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - United States TA - J Comp Neurol JT - The Journal of comparative neurology JID - 0406041 RN - 0 (Nerve Growth Factors) RN - 0 (Neuroprotective Agents) RN - 145172-44-7 (neurotrophin 5) RN - P658DCA9XD (neurotrophin 4) SB - IM MH - Animals MH - Cranial Nerve Injuries/enzymology MH - Denervation/methods MH - Immunohistochemistry MH - Mandibular Nerve/*metabolism MH - Mechanoreceptors/*metabolism MH - Mice MH - Mice, Knockout MH - Nerve Growth Factors/genetics/*metabolism MH - Nerve Regeneration/*physiology MH - Neuroprotective Agents/metabolism MH - Periodontal Ligament/cytology/innervation/*metabolism MH - Trigeminal Nerve Injuries EDAT- 2007/01/25 09:00 MHDA- 2007/03/21 09:00 CRDT- 2007/01/25 09:00 PHST- 2007/01/25 09:00 [pubmed] PHST- 2007/03/21 09:00 [medline] PHST- 2007/01/25 09:00 [entrez] AID - 10.1002/cne.21256 [doi] PST - ppublish SO - J Comp Neurol. 2007 Mar 20;501(3):400-12. doi: 10.1002/cne.21256.