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Induction of interleukin-6 in dorsal root ganglion neurons after gradual elongation of rat sciatic nerve.
Exp Neurol. 2005 Sep; 195(1):61-70.EN

Abstract

In the reconstruction of a segmental defect in injured peripheral nerves, gradual nerve elongation has become an important alternative to nerve grafting. To clarify biochemical responses in peripheral sensory neurons after nerve elongation, we examined the expression of cytokines and neurotrophins related to nerve regeneration. We first established rat elongation models by lengthening left femurs up to 20.0 mm at the rate of 1.0, 2.0, or 20.0 mm/day. In toluidine blue staining, the acutely elongated, 20-mm/day group showed nuclear eccentricity in the nerve cell body in L5 dorsal root ganglion (DRG) and axonal degeneration in the sciatic nerves; in contrast, the gradually elongated, 1- and 2-mm/day groups remained intact, indicating adaptation. Reverse transcription-polymerase chain reaction analysis revealed that interleukin-6 (IL-6) mRNA was induced in ipsilateral L4-6 DRG in an elongation rate-dependent manner. In contrast, none of the elongated groups exhibited a significant change in mRNA levels for interleukin-1beta, tumor necrosis factor-alpha, nerve growth factor, brain-derived neurotrophic factor, neurotropnin-3, and neurotrophin-4/5. Levels of IL-6 mRNA in all the elongated groups reached the maximum level at day 4 after 20-mm lengthening, while the axotomized group showed a decrease from the maximum level at day 1. Induction of IL-6 mRNA was also detected in the contralateral L4-6 DRG of all the elongated groups, but not detected in the axotomized group. In histochemical analysis, IL-6-immunoreactivity was predominant in neurofilament-positive, medium to large DRG neurons. Application of IL-6 to cultured Schwann cells increased mRNA for peripheral myelin protein 22 (PMP22), a major myelin component. These results suggest that IL-6 plays a key role in biochemical responses in peripheral sensory neurons after gradual nerve elongation.

Authors+Show Affiliations

Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-8641, Japan. osamura@med.kanazawa-u.ac.jpNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15913608

Citation

Osamura, Naoki, et al. "Induction of Interleukin-6 in Dorsal Root Ganglion Neurons After Gradual Elongation of Rat Sciatic Nerve." Experimental Neurology, vol. 195, no. 1, 2005, pp. 61-70.
Osamura N, Ikeda K, Ito T, et al. Induction of interleukin-6 in dorsal root ganglion neurons after gradual elongation of rat sciatic nerve. Exp Neurol. 2005;195(1):61-70.
Osamura, N., Ikeda, K., Ito, T., Higashida, H., Tomita, K., & Yokoyama, S. (2005). Induction of interleukin-6 in dorsal root ganglion neurons after gradual elongation of rat sciatic nerve. Experimental Neurology, 195(1), 61-70.
Osamura N, et al. Induction of Interleukin-6 in Dorsal Root Ganglion Neurons After Gradual Elongation of Rat Sciatic Nerve. Exp Neurol. 2005;195(1):61-70. PubMed PMID: 15913608.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Induction of interleukin-6 in dorsal root ganglion neurons after gradual elongation of rat sciatic nerve. AU - Osamura,Naoki, AU - Ikeda,Kazuo, AU - Ito,Takaaki, AU - Higashida,Haruhiro, AU - Tomita,Katsuro, AU - Yokoyama,Shigeru, PY - 2005/01/07/received PY - 2005/03/25/revised PY - 2005/03/30/accepted PY - 2005/5/26/pubmed PY - 2005/10/28/medline PY - 2005/5/26/entrez SP - 61 EP - 70 JF - Experimental neurology JO - Exp Neurol VL - 195 IS - 1 N2 - In the reconstruction of a segmental defect in injured peripheral nerves, gradual nerve elongation has become an important alternative to nerve grafting. To clarify biochemical responses in peripheral sensory neurons after nerve elongation, we examined the expression of cytokines and neurotrophins related to nerve regeneration. We first established rat elongation models by lengthening left femurs up to 20.0 mm at the rate of 1.0, 2.0, or 20.0 mm/day. In toluidine blue staining, the acutely elongated, 20-mm/day group showed nuclear eccentricity in the nerve cell body in L5 dorsal root ganglion (DRG) and axonal degeneration in the sciatic nerves; in contrast, the gradually elongated, 1- and 2-mm/day groups remained intact, indicating adaptation. Reverse transcription-polymerase chain reaction analysis revealed that interleukin-6 (IL-6) mRNA was induced in ipsilateral L4-6 DRG in an elongation rate-dependent manner. In contrast, none of the elongated groups exhibited a significant change in mRNA levels for interleukin-1beta, tumor necrosis factor-alpha, nerve growth factor, brain-derived neurotrophic factor, neurotropnin-3, and neurotrophin-4/5. Levels of IL-6 mRNA in all the elongated groups reached the maximum level at day 4 after 20-mm lengthening, while the axotomized group showed a decrease from the maximum level at day 1. Induction of IL-6 mRNA was also detected in the contralateral L4-6 DRG of all the elongated groups, but not detected in the axotomized group. In histochemical analysis, IL-6-immunoreactivity was predominant in neurofilament-positive, medium to large DRG neurons. Application of IL-6 to cultured Schwann cells increased mRNA for peripheral myelin protein 22 (PMP22), a major myelin component. These results suggest that IL-6 plays a key role in biochemical responses in peripheral sensory neurons after gradual nerve elongation. SN - 0014-4886 UR - https://www.unboundmedicine.com/medline/citation/15913608/Induction_of_interleukin_6_in_dorsal_root_ganglion_neurons_after_gradual_elongation_of_rat_sciatic_nerve_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0014-4886(05)00120-2 DB - PRIME DP - Unbound Medicine ER -