Examination of a hypothesis that thining of the cerebral cortex in congenital hydrocephalus is caused by delayd neuronal differentiation

• Project/Area Number: 07807130
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Cerebral neurosurgery
• Research Institution: Kochi Medical School
• Principal Investigator: SAKAMOTO Takashi Kochi Medical School, Research Associate, 医学部, 助手 (90243823)
• Co-Investigator(Kenkyū-buntansha): MIMA Tatsuo Kochi Medical School, Research Associate, 医学部, 助手 (30192363)
• Project Period (FY): 1995 – 1996
• Project Status: Completed (Fiscal Year 1996)
• Budget Amount: ¥1,800,000 (Direct Cost: ¥1,800,000); Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000); Fiscal Year 1995: ¥1,300,000 (Direct Cost: ¥1,300,000)
• Keywords: hydrocephalus / neuronal differentiation / neurotrophic factor / nerve growth factor / neurotrophin 3 / brain-derived neurotrophic factor / rat / nerve growth factor / 繊維芽細胞増殖因子 / 神経成長因子

Research Abstract

We examined whether aberrant expression of neurotrophic factors and delayd neurinal differentiation occurs in congenital hydrocephalus HTX rats. HTX rats were sacrificed at postnatal day 3 (P3) and day 6 (P6), and immunohistochemical analysis was conducted to see localization and expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), and receptor TrkB.Wistar rats were used for controls.
The cerebral cortex : NGF were hardly immunostained in both HTX and Wistar rat groups. BDNF were diffusely stained in all the cerebral cortex in controls, while in HTX rats the immunoreactivity was observed only in the 2nd and 3rd layrs where strongly stained and faintly stained cells were intermingled. NT-3 were stained difusely in the cytoplasm of the cell in controls but in the nucleus in HTX rats. This finding in HTX rats was observed in the earlier stage of control rats, suggesting that neuronal differentiation may be delayd in HTX rats. Expression of TrkB were less in HTX rats compared to controls.
The hippocampus : Immunostaining of NGF,similar to the finding in the cerebral cortex, was hardly detected in either control or HTX rats. BDNF was stained in the stratum radiatum and the oriens layr in both groups. Its immunoreactivity in controls decreased as the development proceeded, however, in HTX rats was still strong at P6, suggesting the delayd neuronal differentiation in HTX rats. NT-3 was immunostained in the oriens layr, and the reactivity was similar in both groups. In the pyramidal layrs, all the three neurotrophic factors did not show any difference between the two groups.
Some results in this study suggest that neuronal differentiation may be delayd in congenital hydrocephalus HTX rats. To confirm those immunohistochemical findings, we are now conducting the quantitative analysis with RT-PCR.