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Myelinated fiber regeneration after crush injury is retarded in sciatic nerves of aging mice.
J Comp Neurol. 1991 Jun 08; 308(2):180-7.JC

Abstract

To compare nerve regeneration in young adult and aging mice, the right sciatic nerves of 6- and 24-month-old mice were crushed at the sciatic notch. Two weeks later, both groups of mice were perfused with an aldehyde solution, and, after additional fixation, the sciatic nerves were processed so that the transverse sections of each nerve subsequently studied by light and electron microscopy included the entire posterior tibial fascicle 5 mm distal to the crush site. The same level was sectioned in unoperated contralateral nerves; these nerves served as controls. Electron micrographs and the Bioquant Image Analysis System IV were used to measure areas of posterior tibial fascicles and count the number of myelinated axons, the number of unmyelinated axons, and their frequency in Schwann cell units. In aging mice, the total number of regenerating myelinated axons was significantly reduced, but totals of regenerating unmyelinated axons in aging and young adults did not differ significantly. In aging mice, the frequency of Schwann cells that contained a single unmyelinated axon was greater, suggesting that before myelination began, Schwann cell ensheathment of axons also was slowed. After axotomy by a crush injury, the area of the posterior tibial fascicle was less than that in young adults and the distal disintegration of myelin sheath remnants also appeared to be retarded. The results indicate that responses of neurons, axons, and Schwann cells could be important in slowing the regeneration of myelinated fibers found in sciatic nerves from aging mice.

Authors+Show Affiliations

Laboratory of Experimental Neuropathology, NINDS, National Institutes of Health, Bethesda, Maryland 20892.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

1890237

Citation

Tanaka, K, and H D. Webster. "Myelinated Fiber Regeneration After Crush Injury Is Retarded in Sciatic Nerves of Aging Mice." The Journal of Comparative Neurology, vol. 308, no. 2, 1991, pp. 180-7.
Tanaka K, Webster HD. Myelinated fiber regeneration after crush injury is retarded in sciatic nerves of aging mice. J Comp Neurol. 1991;308(2):180-7.
Tanaka, K., & Webster, H. D. (1991). Myelinated fiber regeneration after crush injury is retarded in sciatic nerves of aging mice. The Journal of Comparative Neurology, 308(2), 180-7.
Tanaka K, Webster HD. Myelinated Fiber Regeneration After Crush Injury Is Retarded in Sciatic Nerves of Aging Mice. J Comp Neurol. 1991 Jun 8;308(2):180-7. PubMed PMID: 1890237.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Myelinated fiber regeneration after crush injury is retarded in sciatic nerves of aging mice. AU - Tanaka,K, AU - Webster,H D, PY - 1991/6/8/pubmed PY - 1991/6/8/medline PY - 1991/6/8/entrez SP - 180 EP - 7 JF - The Journal of comparative neurology JO - J Comp Neurol VL - 308 IS - 2 N2 - To compare nerve regeneration in young adult and aging mice, the right sciatic nerves of 6- and 24-month-old mice were crushed at the sciatic notch. Two weeks later, both groups of mice were perfused with an aldehyde solution, and, after additional fixation, the sciatic nerves were processed so that the transverse sections of each nerve subsequently studied by light and electron microscopy included the entire posterior tibial fascicle 5 mm distal to the crush site. The same level was sectioned in unoperated contralateral nerves; these nerves served as controls. Electron micrographs and the Bioquant Image Analysis System IV were used to measure areas of posterior tibial fascicles and count the number of myelinated axons, the number of unmyelinated axons, and their frequency in Schwann cell units. In aging mice, the total number of regenerating myelinated axons was significantly reduced, but totals of regenerating unmyelinated axons in aging and young adults did not differ significantly. In aging mice, the frequency of Schwann cells that contained a single unmyelinated axon was greater, suggesting that before myelination began, Schwann cell ensheathment of axons also was slowed. After axotomy by a crush injury, the area of the posterior tibial fascicle was less than that in young adults and the distal disintegration of myelin sheath remnants also appeared to be retarded. The results indicate that responses of neurons, axons, and Schwann cells could be important in slowing the regeneration of myelinated fibers found in sciatic nerves from aging mice. SN - 0021-9967 UR - https://www.unboundmedicine.com/medline/citation/1890237/Myelinated_fiber_regeneration_after_crush_injury_is_retarded_in_sciatic_nerves_of_aging_mice_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0021-9967&date=1991&volume=308&issue=2&spage=180 DB - PRIME DP - Unbound Medicine ER -