title: Evaluation of cellular organization and axonal regeneration through linear PLA foam implants in acute and chronic spinal cord injury.
abstract: There are few studies of neural implants in spinal cord injury (SCI) focused on supporting directed axon growth. In this study, we fabricated a macroporous poly (lactic acid) (PLA) foam with oriented inner channels. Amorphous foam without linear channels served as a control in an acute SCI injury model, and the effectiveness of foam with linear channels was further investigated in a chronic SCI model. Implants were placed into a 2 mm hemisection lesion cavity at the T8 spinal cord level in adult rats. Two weeks post-implantation, tissue sections including the implants were examined using antibodies against GFAP, p75, ED-1, laminin, GAP-43, and CGRP. Foam implants were well-integrated with the host spinal cord. In linear foams, numerous DAPI-stained cells were found within the inner channels. Schwann cells but not astrocytes had migrated within the channels. Intense laminin staining was observed throughout the extracellular matrix substrate. GAP-43- and CGRP-positive axons grew through the implants following the linear channels. In the amorphous control foams, DAPI staining distributed evenly through the pores. However, the growth of GAP-43 or CGRP-positive axons was misguided and impeded at the entrance area of the foam. Higher numbers of GAP-43 and CGRP-positive axons grew into linear foam implants after chronic SCI than acute SCI. These results suggest the potential application of linear foam implants in cell and axon guidance for SCI repair, especially for chronic SCI.
authors.affiliation: Department of Physiology, University of Kentucky, Lexington, Kentucky 40536-0298, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Cai
authors.forename: Kristine S
authors.initials: KS
authors.lastname: Ziemba
authors.forename: George M
authors.initials: GM
authors.lastname: Smith
authors.forename: Ying
authors.initials: Y
authors.lastname: Jin
mesh_terms: D000208:Acute Disease; D000818:Animals; D001369:Axons / Q000502:physiology*; D001672:Biocompatible Materials / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002908:Chronic Disease; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D019922:GAP-43 Protein / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology; D008855:Microscopy, Electron, Scanning; D009416:Nerve Regeneration / Q000502:physiology*; D016348:Osseointegration / Q000502:physiology; D011091:Polyesters; D011108:Polymers / Q000378:metabolism*; D019736:Prostheses and Implants; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000473:pathology*
chemical_list: D001672:Biocompatible Materials; D019922:GAP-43 Protein; D007473:Ion Channels; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D015740:Calcitonin Gene-Related Peptide