title: Ultrasound-stimulated peripheral nerve regeneration within asymmetrically porous PLGA/Pluronic F127 nerve guide conduit.
abstract: Recently, we developed a novel method to fabricate a nerve guide conduit (NGC) with asymmetrical pore structure and hydrophilicity using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method. From the animal study using a rat model (sciatic nerve defect of rat), we recognized that the unique PLGA/Pluronic F127 tube provided good environments for nerve regeneration. In this study, we applied low-intensity pulsed ultrasound as a simple and noninvasive stimulus at the PLGA/F127 NGC-implanted site transcutaneously in rats to investigate the feasibility of ultrasound for the enhanced nerve regeneration through the tube. The nerve regeneration behaviors within the ultrasound-stimulated PLGA/Pluronic F127 NGCs were compared with the NGCs without the ultrasound treatment as well as normal nerve by histological and immunohistochemical observations. It was observed that the PLGA/Pluronic F127 tube-implanted group applied with the ultrasound had more rapid nerve regeneration behavior (approximately 0.71 mm/day) than the tube-implanted group without the ultrasound treatment (approximately 0.48 mm/day). The ultrasound-treated tube group also showed greater neural tissue area as well as larger axon diameter and thicker myelin sheath than the tube group without the ultrasound treatment, indicating better nerve regeneration. The better nerve regeneration behavior in the our NGC/ultrasound system may be caused by the synergistic effect of the asymmetrically porous PLGA/Pluronic F127 tube with unique properties (selective permeability, hydrophilicity, and structural stability, which can provide good environment for nerve regeneration) and physical stimulus (stimulation of the Schwann cells and activation of the neurotrophic factors).
authors.affiliation: Department of Advanced Materials, Hannam University, Daejeon 305-811, South Korea.
authors.forename: Sang Chul
authors.initials: SC
authors.lastname: Park
authors.affiliation: Department of Advanced Materials, Hannam University, Daejeon 305-811, South Korea.
authors.forename: Se Heang
authors.initials: SH
authors.lastname: Oh
authors.affiliation: Department of Oriental Medicine, Daejeon University, Daejeon 300-716, South Korea.
authors.forename: Tae Beom
authors.initials: TB
authors.lastname: Seo
authors.affiliation: Department of Oriental Medicine, Daejeon University, Daejeon 300-716, South Korea.
authors.forename: Uk
authors.initials: U
authors.lastname: Namgung
authors.affiliation: Department of Pathology, Cancer Research Institute, Chungnam National University School of Medicine, Daejeon 301-131, South Korea.
authors.forename: Jin Man
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Department of Advanced Materials, Hannam University, Daejeon 305-811, South Korea.
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000818:Animals; D048091:Guided Tissue Regeneration / Q000379:methods* / Q000592:standards; D019344:Lactic Acid; D009414:Nerve Growth Factors / Q000378:metabolism; D009416:Nerve Regeneration / Q000528:radiation effects*; D010525:Peripheral Nerves / Q000502:physiology* / Q000528:radiation effects; D020442:Poloxamer; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity; D051381:Rats; D012583:Schwann Cells / Q000528:radiation effects; D014464:Ultrasonic Therapy / Q000379:methods*; D014465:Ultrasonics
chemical_list: D009414:Nerve Growth Factors; D020442:Poloxamer; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid