BDNF rescues myosin heavy chain IIB muscle fibers after neonatal nerve injury

• Published in: American Journal of Physiology: Cell Physiology Vol. 287; no. 1; pp. C22 - C29
• Main Authors: Mousavi, Kambiz, Parry, David J, Jasmin, Bernard J
• Format: Journal Article
• Language: English
• Published: United States 01.07.2004
• Subjects: Animals; Animals, Newborn; Brain-Derived Neurotrophic Factor - metabolism; Brain-Derived Neurotrophic Factor - pharmacology; Ciliary Neurotrophic Factor - pharmacology; Drug Combinations; Hindlimb; Muscle Fibers, Skeletal - drug effects; Muscle Fibers, Skeletal - metabolism; Muscle, Skeletal - drug effects; Muscle, Skeletal - metabolism; Muscle, Skeletal - physiopathology; Myosin Heavy Chains - metabolism; Nerve Crush; Nonmuscle Myosin Type IIB - metabolism; Rats; Sciatic Nerve - injuries; Wounds and Injuries - physiopathology
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00583.2003

Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5 Submitted 29 December 2003 ; accepted in final form 6 February 2004 Neonatal sciatic nerve injury is known to result in an extensive loss of lumbar motor neurons as well as the disappearance of their respective muscle fibers in the hindlimb musculature. The loss of motor neurons and muscle fibers can be prevented by immediate administration of target-derived neurotrophic factors to the site of injury. In the present study, we investigated the role of ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) in the survival and maturation of a subset of motor neurons innervating the extensor digitorum longus (EDL) and tibialis anterior (TA) muscles. We have shown that combined administration of CNTF and BDNF prevented the loss of motor units after neonatal nerve injury and contributed to the maintenance of muscle mass. Importantly, this combined neurotrophin regimen also prevented the disappearance of muscle fibers that express myosin heavy chain IIB (MyHC IIB) in both EDL and TA muscles 3 mo after neonatal sciatic nerve crush. In parallel studies, we observed a higher level of BDNF in EDL muscle during the critical period of development when motor neurons are highly susceptible to target removal. Given our previous findings that combined administration of CNTF with neurotrophin-3 (NT-3) or neurotrophin-4/5 (NT-4/5) did not result in the rescue of MyHC IIB fibers in EDL, the present results show the importance of muscle-derived BDNF in the survival and maturation of a subpopulation of motor neurons and of MyHC IIB muscle fibers during neonatal development of the neuromuscular system. motor neurons; neuromuscular development; neurotrophins Address for reprint requests and other correspondence: B. J. Jasmin, Dept. of Cellular and Molecular Medicine, Univ. of Ottawa, 451 Smyth Rd., Ottawa, Ontario, Canada K1H 8M5 (E-mail: jasmin{at}uottawa.ca ).