Environmental factors involved in axonal regeneration following spinal cord transection in rats.
A recent study of a rat model treated with grafted collagen filament (CF) after spinal cord transection showed dramatic recovery of motor function but did not report on the acute-stage phenomenon. In the present study, we describe molecular and histological aspects of the axonal regeneration process during the acute stage following spinal cord transection. The spinal cord of 8-week-old rats was completely transected, and a scaffold of almost the same size as the resected portion was implanted in the gap. Changes in the mRNA expression of four neurotrophic factors [nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), NT-3, and glial cell-derived neurotrophic factor (GDNF)] were analyzed after 72 h. The expression of BDNF and NT-3 mRNA increased significantly in the CF-grafted group compared to the nongrafted group. Immunostaining for BDNF and NT-3 revealed that cells positive for these neurotrophic factors extended along the collagen filaments in the CF-grafted group. Similarly, astrocytes extended into the collagen filament scaffold together with the neurotrophic factors and partly across a border line. These findings indicate that collagen filament helps to reduce scar tissue, supports the expression of neurotrophic factors, and serves as a scaffold for the outgrowth of regenerating axons.
Department of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan.
Takahiro
T
Yara
Yoshihiko
Y
Kato
Hideo
H
Kataoka
Tsukasa
T
Kanchiku
Hidenori
H
Suzuki
Toshikazu
T
Gondo
Satoru
S
Yoshii
Toshihiko
T
Taguchi
D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D005260:Female; D048091:Guided Tissue Regeneration / Q000379:methods*; D020007:Implants, Experimental; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D009416:Nerve Regeneration / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D013119:Spinal Cord Injuries / Q000503:physiopathology*
D009414:Nerve Growth Factors; D003094:Collagen