title: Abnormal sensory and motor reinnervation of rat muscle spindles following nerve transection and suture.
abstract: Muscle spindles from the lower lumbrical muscles of rats were studied by transmission and scanning electron microscopy following reinnervation (i) after a single sciatic nerve crush lesion and (ii) after transection and immediate epineurial suture of the sciatic nerve. In all muscle spindles, regenerated sensory or motor nerve endings were encountered 3 months after making the lesions although in the nerve-transection group, regenerated nerve endings were seen less frequently before 6 months of recovery. Abnormalities in reinnervated spindles following neurotomy comprised: (1) multiplicity of axonal sprouts (hyperinnervation), sometimes irregularly related to, although never in direct contact with, regenerated sensory nerve endings; (2) altered contact relationships between sensory nerve endings and intrafusal muscle fibers; (3) abnormal structure of nerve endings; and (4) irregular association of Schwann cell processes to regenerated sensory nerve endings. These findings indicate that reinnervation of muscle spindles following transection and suture of a peripheral nerve, i.e., after complete interruption of its continuity, in fact, occurs although the fine structural abnormalities observed are supposed to interfere with adequate functional restoration.
authors.affiliation: Institut für Neuropathologie, Klinikum der Rheinisch-Westfälischen Technischen Hochschule, Aachen, Federal Republic of Germany.
authors.forename: R
authors.initials: R
authors.lastname: Dieler
authors.forename: J M
authors.initials: JM
authors.lastname: Schröder
mesh_terms: D000818:Animals; D005260:Female; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009046:Motor Neurons / Q000502:physiology / Q000648:ultrastructure*; D009121:Muscle Denervation; D009132:Muscles / Q000294:innervation* / Q000648:ultrastructure; D009469:Neuromuscular Junction / Q000502:physiology / Q000648:ultrastructure*; D009475:Neurons, Afferent / Q000502:physiology / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains; D012584:Sciatic Nerve / Q000502:physiology