Growth-promoting activity of Hominis Placenta extract on regenerating sciatic nerve.
OBJECTIVE
Extract of Hominis Placenta (HP) has been used in oriental medicine as an agent for improving physiological function. The present study was conducted to investigate whether HP treatment in an experimental sciatic nerve injury animal model produces growth-promoting effects on regenerating peripheral nerve fibers after injury.


METHODS
After HP was injected into a sciatic nerve injury site, changes in protein levels were analyzed in the regenerating nerve area by Western blotting and immunofluorescence staining analyses. For quantitative assessment of axonal regeneration, a retrograde tracing technique was used to identify the neuronal cell bodies corresponding to regenerating axons, and the extent of neurite outgrowth in cultured dorsal root ganglia (DRG) sensory neurons prepared from animals that had experienced a sciatic nerve crush injury 7 d before neuron collection was analyzed.


RESULTS
Induction levels of axonal growth-associated protein (GAP-43) in the injured sciatic nerves were elevated by HP treatment. HP treatment also upregulated cell division cycle 2 (Cdc2) protein levels in the distal stump of the injured sciatic nerve. Induced Cdc2 protein was detected in Schwann cells, suggesting that Cdc2 kinase activity may be involved in the growth-promoting activity of regenerating axons via Schwann cell proliferation. Cell body measurement by retrograde tracing indicated that HP treatment produced significant increases in regenerating motor axons. Finally, HP treatment of cultured DRG sensory neurons significantly increased neurite arborization and elongation.


CONCLUSIONS
HP promotes the regeneration of injured sciatic axons by upregulating the synthesis of regeneration-related protein factors such as GAP-43 and Cdc2.
Seo
Tae-beom Seo
TB
Department of Oriental Medicine, Daejeon University, Korea.
Han
In-sun
IS
Yoon
Jin-hwan
JH
Seol
In-chan Seol
IC
Kim
Yun-sik
YS
Jo
Hyun-kyung
HK
An
Joung-jo
JJ
Hong
Kwon-eui
KE
Seo
Young-bae
YB
Kim
Dong-hee
DH
Park
Seung-kiel
SK
Yang
Deok-chun
DC
Namgung
Uk
U
D000818:Animals; D001369:Axons / Q000502:physiology; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002478:Cells, Cultured; D019922:GAP-43 Protein / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008297:Male; D009416:Nerve Regeneration / Q000502:physiology*; D016501:Neurites / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010924:Placental Extracts / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries / Q000378:metabolism / Q000502:physiology*
D019922:GAP-43 Protein; D010924:Placental Extracts; D016203:CDC2 Protein Kinase