| Co-Investigator(Kenkyū-buntansha) |
HAYASHI Kyozo Gifu Pharmaceurical Univ., Dept. of Pharm. Prof., 薬学部, 教授 (00029935)
FURUKAWA Shoei Gifu pharmaceurical Univ., Dept. of Pharm. As. Prof., 薬学部, 助教授 (90159129)
NAKAMURA Nobuyuki Jikeikai Med. School of Medicine, Dept. of Med. Lecturer, 医学部, 助手 (90198226)
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| Research Abstract |
Nerve growth factor (NGF) is a target derived trophic agent which promotes the survival and cellular metabolism of sympathetic neurons, neural crest-derived sensory neurons and basal forebrain cholinergic neurons. It is known that the proximal and/or distal stumps of severed nerve in the peripheral nervous system have an increase in NGF levels, and their responses as degeneration or neuronal cell death can be prevented with systemically administered exogenous NGF. The atrophy of cholinergic neurons in aged brain can be prevented with intraventricular administration of NGF. Although the spinal cord injury results the serious functional deficit, the specific function of NGF in the spinal cord is unknown.
With the aim of gaining insight into the specific function of NGF in the spinal cord during degeneration/regeneration, we used the model of spinal cord transection, and determined temporal changes of NGF and NGFmRNA levels after the transection. As NGF displays a broad distribution in each segment (200 to 300 pg/g wet tissue) of spinal cord in young adult rat, we established the model of spinal cord transection (T-6) on 10-week-old Wistar rat. In the beginning at 2 days after transection (2d), NGF displays a significant increase at the rostral stump of transection site (p<0.01). Then, at both (rostral and caudal) stumps, the level of NGF significantly increase 2 to 3-folds at 4d, 2 to 4-folds at 6d. The significant increases of NGF at both stumps are detected from 4d through 8d, and those at the rostral stump are detected from 2d through 21d. At the both stumps, the expression of NGF mRNA increase at 1d,then gradually decrease from 2d though 8d. The increase of NGF and NGFmRNA levels in the both stumps are stimulated by the administration of catechol compound, which is known to be a stimulator of NGF synthesis in cell culture or peripheral nervous system. These results suggest that NGF may play an important role in the regeneration of spinal cord.
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