title: Motoneuron replacement for reinnervation of skeletal muscle in adult rats.
abstract: Reinnervation is needed to rescue muscle when motoneurons die in disease or injury. Embryonic ventral spinal cord cells transplanted into peripheral nerve reinnervate muscle and reduce atrophy, but low motoneuron survival may limit motor unit formation. We tested whether transplantation of a purified population of embryonic motoneurons into peripheral nerve (mean ± SE, 146,458 ± 4,011 motoneurons) resulted in more motor units and reinnervation than transplantation of a mixed population of ventral spinal cord cells (72,075 ± 12,329 motoneurons). Ten weeks after either kind of transplant, similar numbers of neurons expressed choline acetyl transferase and/or Islet-1. Motoneuron numbers always exceeded the reinnervated motor unit count. Most motor end plate were simple plaques. Reinnervation significantly reduced muscle fiber atrophy. These data show that the number of transplanted motoneurons and motoneuron survival do not limit muscle reinnervation. Incomplete differentiation of motoneurons in nerve and lack of muscle activity may result in immature neuromuscular junctions that limit reinnervation and function.
authors.affiliation: The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida 33136-2104, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Grumbles
authors.forename: Vania W
authors.initials: VW
authors.lastname: Almeida
authors.forename: Gizelda T B
authors.initials: GT
authors.lastname: Casella
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Wood
authors.forename: Kamondanai
authors.initials: K
authors.lastname: Hemstapat
authors.forename: Christine K
authors.initials: CK
authors.lastname: Thomas
mesh_terms: D000367:Age Factors; D000818:Animals; D002470:Cell Survival / Q000502:physiology; D005260:Female; D016332:Fetal Tissue Transplantation / Q000379:methods*; D009046:Motor Neurons / Q000637:transplantation*; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology*; D009416:Nerve Regeneration / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D020426:Sciatic Neuropathy / Q000503:physiopathology / Q000601:surgery*