title: Peripheral nerve abnormalities in aging rats.
abstract: The sciatic/tibial/plantar nerve complex of normal aged rats displays striking morphological changes that are most pronounced distally. Nerve fiber abnormalities include: (a) large numbers of axonal glycogenosomes, mitochondria, dense membranous bodies, and decorated particles; (b) adaxonal Schwann cell processes sequestering portions of axoplasm; (c) swollen demyelinated and remyelinated axons, some encircled by supernumerary cellular processes; and (d) collagen pockets, denervated Schwann cell columns, and empty basal laminae. Abnormalities a and b were encountered with increasing frequency on descent through the tibial and plantar nerves. Abnormalities b, c, and d were found in lateral and medial plantar nerves, where they were associated with an enlarged endoneurial space. Found in animals kept in cages with smooth or wire-mesh floors, the incidence of these changes increased with advancing age. They are attributed to trauma and ischemia from chronic pressure on the plantar nerve.
mesh_terms: D000375:Aging; D000818:Animals; D005528:Foot / Q000294:innervation; D008297:Male; D009412:Nerve Fibers / Q000648:ultrastructure; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D010525:Peripheral Nerves / Q000648:ultrastructure*; D051381:Rats; D012584:Sciatic Nerve / Q000648:ultrastructure; D013979:Tibial Nerve / Q000648:ultrastructure