Serum Brain‐derived neurotrophic factor promotes repair and regeneration of aged myelinated fibers via aerobic exercise

Abstract

PurposeDegeneration of the distal peripheral nerve (DPN) with aging is associated with balance and gait disorders. Brain‐derived neurotrophic factor (BDNF) contributes to the repair and remodeling of myelinated fiber. However it is not obvious whether BDNF in the DPN increases with aerobic exercise (AE) in old age and promotes remodeling of MFs. We investigated morphological changes of MFs and BDNF expression levels of both serum and DPN via AE.MethodsEight male wistar rats (aged 95 weeks) were randomly divided into AE and control (Cont) groups. Rats in AE group performed running on the treadmill for 1 hour per day, 6 days per a week during 2 weeks. At 97 weeks of age, the bilateral tibial nerves of 2 groups were removed. To measure myelin thickness and axon diameter, semi‐thin sections of the unilateral specimens were stained with 0.5% Sudan Black B solution following double‐fixation. In addition, each expression level of serum and tissue BDNF in the contralateral specimens was analyzed with enzyme‐linked immunosorbent assay.ResultsMyelin thickness and axon diameter of AE group were significantly larger than those of Cont group (p<0.01). The serum BDNF level of AE group significantly decreased in comparison to that of Cont group (p<0.01). In contrast, BDNF level of AE group was significantly higher than that of Cont group (p<0.01).ConclusionIt was thought that serum BDNFs that were promoted by AE release into nerve fibers and contribute to the remodeling of myelinated fibers in aged DPNs.Support or Funding InformationThe present study was supported by a Grant‐in‐Aid for Scientific Research (C) from the Japan Society for the Promotion of Science (https://kaken.nii.ac.jp; 26350853).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.