Changes in FGF-2 expression in the distal spinal cord stump after complete cord transection: a comparison between infant and adult rats.
METHODS
Expression patterns of fibroblast growth factor-2 (FGF-2) in distal transected spinal cord in infant and adult rats were determined by reverse-transcription polymerase chain reaction (RT-PCR) and immunostaining.


OBJECTIVE
To reveal the expression pattern of FGF-2 in distal transected cord of infant and adult rats.


BACKGROUND
Descending fibers in the spinal cord of infant and adult rats show different regenerative capacity. One explanation is that different levels of FGF-2, an important neurotrophic factor for promoting neurite outgrowth and repair, are expressed in the distal transected cords of the rats, providing different levels of support for severed axons.


METHODS
Spinal cords of infant and adult rats were completely transected. At 12, 24, and 72 hours and at 1 week, segments of distal spinal cord tissues were removed and expression of FGF-2 mRNA was evaluated by RT-PCR. The distribution of FGF-2 and the phenotype of FGF-2-positive cells were determined by immunostaining.


RESULTS
Expression of FGF-2 mRNA was shown to be up-regulated in the distal cord of infant rats but not adult rats. Immunohistochemical analysis showed that neurons in distal cord of infant rats were rich in FGF-2 immunoreactivity (IR), whereas in adult rat neurons FGF-2 IR was hardly observed at all, although a few FGF-2-positive astrocytes were observed in the white matter.


CONCLUSIONS
After complete spinal cord transection, the expression of FGF-2 in the distal cord of infant rats was high compared with that of adults. This may provide neurotrophic support for axonal extension and functional recovery.
Qi
Mei-Ling
ML
Department of Frontier Surgical Therapeutics, Division of Advanced Therapeutical Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Wakabayashi
Yoshiaki
Y
Haro
Hirotaka
H
Shinomiya
Kenichi
K
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D016222:Fibroblast Growth Factor 2 / Q000032:analysis / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000378:metabolism* / Q000601:surgery
D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2