Changes in expression of prosaposin in the rat facial nerve nucleus after facial nerve transection.
Prosaposin is the precursor of saposins A, B, C and D, which are activators of sphingolipid hydrolases. In addition, unprocessed prosaposin functions as a neurotrophic factor in the central and peripheral nervous systems by acting to prevent neuronal apoptosis, to elongate neurites and to facilitate myelination. In this study, the expression pattern of prosaposin in the facial nerve nucleus after facial nerve transection was examined by immunohistochemistry and in situ hybridization. Prosaposin immunoreactivity in the neurons on the operated side facial nerve nucleus showed a biphasic pattern: it was significantly increased on day 3 after transection, decreased dramatically on day 7, started to increase gradually on day 14 and reached another peak on day 21 after transection. Significant increases in the levels of prosaposin mRNA were identified in the neurons on the operated side, suggesting that prosaposin was synthesized vigorously by the neurons themselves in the case of facial nerve transection. The diverse changes in prosaposin immunoreactivity during the process of facial nerve regeneration may reflect the diverse neurotrophic activities of prosaposin in facial motoneurons.
Unuma
Kana
K
Division of Anatomy and Embryology, Department of Integrated Basic Medical Science, Ehime University School of Medicine, Shitsukawa, Toon-shi, Ehime 791-0295, Japan.
Chen
Jie
J
Saito
Shouichiro
S
Kobayashi
Naoto
N
Sato
Kohji
K
Saito
Kyoko
K
Wakisaka
Hiroyuki
H
Mominoki
Katsumi
K
Sano
Akira
A
Matsuda
Seiji
S
D000818:Animals; D002452:Cell Count / Q000379:methods; D003714:Denervation / Q000379:methods; D020220:Facial Nerve Injuries / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D008297:Male; D009046:Motor Neurons / Q000378:metabolism*; D009416:Nerve Regeneration / Q000502:physiology; D011149:Pons / Q000166:cytology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D049231:Saposins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
C483347:Psap protein, rat; D012333:RNA, Messenger; D049231:Saposins