Alginate enhances elongation of early regenerating axons in spinal cord of young rats.
Freeze-dried alginate sponge cross-linked with covalent bonds has been demonstrated to enhance nerve regeneration in peripheral nerves and spinal cords. The present study examined, at early stages after surgery, the outgrowth of regenerating axons and reactions of astrocytes at the stump of transected spinal cord in young rats. Two segments (Th7-8) were resected, and alginate was implanted in the lesion. As controls, collagen gel was implanted in place of alginate or the lesion was left without implantation. Two and 4 weeks after surgery, nerve outgrowth and astrocyte reactions were examined. Many regenerating axons, some of which were accompanied by astrocytic processes, were found to extend from the stump into the alginate-implanted lesion. In the all nonimplanted animals, large cystic cavities were formed at both interfaces with no definite axonal outgrowth into the lesion. In collagen-implanted animals, cavity formation was found in some rats, and regenerating axons once formed at the stumps did not extend further into the lesion. Astrocytic processes extending into alginate-implanted lesion had no basal laminae, whereas those found in control experiments were covered by basal laminae. These findings suggest that alginate contributed to reducing the barrier composed of connective tissues and reactive astrocytic processes, and served as a scaffold for the outgrowth of regenerating axons and elongation of astrocytic processes.
Kataoka
Kazuya
K
Department of Plastic and Reconstructive Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Suzuki
Yoshihisa
Y
Kitada
Masaaki
M
Hashimoto
Tadashi
T
Chou
Hirotomi
H
Bai
Hongliang
H
Ohta
Masayoshi
M
Wu
Sufan
S
Suzuki
Kyoko
K
Ide
Chizuka
C
D000464:Alginates / Q000494:pharmacology*; D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D001672:Biocompatible Materials / Q000494:pharmacology*; D003094:Collagen / Q000494:pharmacology; D020723:Glucuronic Acid / Q000494:pharmacology*; D006603:Hexuronic Acids / Q000494:pharmacology*; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009416:Nerve Regeneration / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D013116:Spinal Cord / Q000648:ultrastructure; D013119:Spinal Cord Injuries / Q000188:drug therapy*
D000464:Alginates; D001672:Biocompatible Materials; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D003094:Collagen