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Long-term effects of a lumbosacral ventral root avulsion injury on axotomized motor neurons and avulsed ventral roots in a non-human primate model of cauda equina injury.
Neuroscience. 2013 Oct 10; 250:129-39.N

Abstract

Here, we have translated from the rat to the non-human primate a unilateral lumbosacral injury as a model for cauda equina injury. In this morphological study, we have investigated retrograde effects of a unilateral L6-S2 ventral root avulsion (VRA) injury as well as the long-term effects of Wallerian degeneration on avulsed ventral roots at 6-10 months post-operatively in four adult male rhesus monkeys. Immunohistochemistry for choline acetyl transferase and glial fibrillary acidic protein demonstrated a significant loss of the majority of the axotomized motoneurons in the affected L6-S2 segments and signs of an associated astrocytic glial response within the ventral horn of the L6 and S1 spinal cord segments. Quantitative analysis of the avulsed ventral roots showed that they exhibited normal size and were populated by a normal number of myelinated axons. However, the myelinated axons in the avulsed ventral roots were markedly smaller in caliber compared to the fibers of the intact contralateral ventral roots, which served as controls. Ultrastructural studies confirmed the presence of small myelinated axons and a population of unmyelinated axons within the avulsed roots. In addition, collagen fibers were readily identified within the endoneurium of the avulsed roots. In summary, a lumbosacral VRA injury resulted in retrograde motoneuron loss and astrocytic glial activation in the ventral horn. Surprisingly, the Wallerian degeneration of motor axons in the avulsed ventral roots was followed by a repopulation of the avulsed roots by small myelinated and unmyelinated fibers. We speculate that the small axons may represent sprouting or axonal regeneration by primary afferents or autonomic fibers.

Authors+Show Affiliations

Department of Clinical Neuroscience, Division of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden; Department of Anesthesiology & Perioperative Care, University of California at Irvine, Irvine, CA, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

23830908

Citation

Ohlsson, M, et al. "Long-term Effects of a Lumbosacral Ventral Root Avulsion Injury On Axotomized Motor Neurons and Avulsed Ventral Roots in a Non-human Primate Model of Cauda Equina Injury." Neuroscience, vol. 250, 2013, pp. 129-39.
Ohlsson M, Nieto JH, Christe KL, et al. Long-term effects of a lumbosacral ventral root avulsion injury on axotomized motor neurons and avulsed ventral roots in a non-human primate model of cauda equina injury. Neuroscience. 2013;250:129-39.
Ohlsson, M., Nieto, J. H., Christe, K. L., & Havton, L. A. (2013). Long-term effects of a lumbosacral ventral root avulsion injury on axotomized motor neurons and avulsed ventral roots in a non-human primate model of cauda equina injury. Neuroscience, 250, 129-39. https://doi.org/10.1016/j.neuroscience.2013.06.054
Ohlsson M, et al. Long-term Effects of a Lumbosacral Ventral Root Avulsion Injury On Axotomized Motor Neurons and Avulsed Ventral Roots in a Non-human Primate Model of Cauda Equina Injury. Neuroscience. 2013 Oct 10;250:129-39. PubMed PMID: 23830908.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Long-term effects of a lumbosacral ventral root avulsion injury on axotomized motor neurons and avulsed ventral roots in a non-human primate model of cauda equina injury. AU - Ohlsson,M, AU - Nieto,J H, AU - Christe,K L, AU - Havton,L A, Y1 - 2013/07/02/ PY - 2012/09/24/received PY - 2013/06/03/revised PY - 2013/06/19/accepted PY - 2013/7/9/entrez PY - 2013/7/9/pubmed PY - 2014/4/5/medline KW - ChAT KW - GFAP KW - PBS KW - VRA KW - Wallerian degeneration KW - choline acetyltransferase KW - electron microscopy KW - glial fibrillary acidic protein KW - phosphate-buffered saline KW - rhesus macaque KW - spinal cord KW - ventral root avulsion SP - 129 EP - 39 JF - Neuroscience JO - Neuroscience VL - 250 N2 - Here, we have translated from the rat to the non-human primate a unilateral lumbosacral injury as a model for cauda equina injury. In this morphological study, we have investigated retrograde effects of a unilateral L6-S2 ventral root avulsion (VRA) injury as well as the long-term effects of Wallerian degeneration on avulsed ventral roots at 6-10 months post-operatively in four adult male rhesus monkeys. Immunohistochemistry for choline acetyl transferase and glial fibrillary acidic protein demonstrated a significant loss of the majority of the axotomized motoneurons in the affected L6-S2 segments and signs of an associated astrocytic glial response within the ventral horn of the L6 and S1 spinal cord segments. Quantitative analysis of the avulsed ventral roots showed that they exhibited normal size and were populated by a normal number of myelinated axons. However, the myelinated axons in the avulsed ventral roots were markedly smaller in caliber compared to the fibers of the intact contralateral ventral roots, which served as controls. Ultrastructural studies confirmed the presence of small myelinated axons and a population of unmyelinated axons within the avulsed roots. In addition, collagen fibers were readily identified within the endoneurium of the avulsed roots. In summary, a lumbosacral VRA injury resulted in retrograde motoneuron loss and astrocytic glial activation in the ventral horn. Surprisingly, the Wallerian degeneration of motor axons in the avulsed ventral roots was followed by a repopulation of the avulsed roots by small myelinated and unmyelinated fibers. We speculate that the small axons may represent sprouting or axonal regeneration by primary afferents or autonomic fibers. SN - 1873-7544 UR - https://www.unboundmedicine.com/medline/citation/23830908/Long_term_effects_of_a_lumbosacral_ventral_root_avulsion_injury_on_axotomized_motor_neurons_and_avulsed_ventral_roots_in_a_non_human_primate_model_of_cauda_equina_injury_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0306-4522(13)00560-5 DB - PRIME DP - Unbound Medicine ER -