Different expressions of BDNF, NT3, and NT4 in muscle and nerve after various types of peripheral nerve injuries

Abstract

The changes in the expression of brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4) in the rat neuromuscular system as a result of three different types of sciatic nerve injuries have been evaluated. The changes in mRNA and protein levels for BDNF, NT-3, and NT-4 in the soleus muscle and sciatic nerve were assessed 4-28 days after sciatic nerve transection (neurotmesis), sciatic nerve crush (axonotmesis), and mild acute compression (neurapraxia). BDNF mRNA levels increased dramatically with nerve transection in the soleus muscle and the sciatic nerve 7-14 days after injury, whereas the changes were low in other types of injury. The changes of protein levels for BDNF were also similar. The mRNA and the protein levels of NT-3 in the soleus muscle did not show any significant difference. The mRNA for NT-4 in the soleus muscle decreased from 4 to 14 days after sciatic nerve transection, and the protein level was also minimum 14 days after sciatic nerve transection. Our results indicate that the neurotrophic factors in the neuromuscular system could play a role in differentiating peripheral nerve injury.

Enhanced Transmission at a Spinal Synapse TriggeredIn Vivoby an Injury Signal Independent of Altered Synaptic Activity

“…In contrast, the neurotrophin BDNF is a viable candidate by our criteria. BDNF increases at the injury site soon after axonal injury (Murphy et al, 1995;Omura et al, 2005) and in large DRG (IA) cell bodies of crushed primary axons (Cho et al, 1998;Michael et al, 1999); it is transported centrally when bound to its TrkB receptor, although the exact transport mechanism remains uncertain (Ginty and Segal, 2002). Also, BDNF trafficking can be influenced by neuronal activity (Nagappan and Lu, 2005), and if it were somehow impeded by stimulating axons electrically, then BDNF would meet all of our criteria.…”

Complementary Actions of BDNF and Neurotrophin-3 on the Firing Patterns and Synaptic Composition of Motoneurons

“…The sequence of events for neurotrophins as target-derived factors is established. Neurotrophins are produced by muscle cells (Steljes et al, 1999;Omura et al, 2005) and then retrogradely and transsynaptically transported by motoneurons (Rind et al, 2005) that are endowed with neurotrophin receptors (Benítez-Temiño et al, 2004). Retrograde neurotrophin uptake and transport increases after nerve injury (Curtis et al, 1998), and neurotrophin signaling reaches the soma which influences cellular functions by different effectors and transcriptional pathways (Zweifel et al, 2005).…”

Growth/differentiation factor-15 and its role in peripheral nervous system lesion and regeneration

“…brain-derived neurotrophic factor (BDNF) (Omura et al, 2005;Tolwani et al, 2004;Xiao et al, 2009;Yamauchi et al, 2004), and insulin-like growth factors (IGF-1/2) (Cheng et al, 2000;Silva et al, 2009). Schwann cells also produce myelin structrue proteins to construct myelin sheaths: myelin protein zero (P0) (Trapp, 1988), myelin basic protein (MBP) (Topilko et al, 1994), peripheral myelin protein 22 (PMP22) (Snipes et al, 1999), and myelin-associate-glycoprotein (MAG) (Trapp, 1988).…”