DEVELOPMENT OF THE EARLY INDICATOR FOR LATE RADIATION DAMAGE

Research Project

Project/Area Number	10670858
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Radiation science
Research Institution	KYUSHU UNIVERSITY
Principal Investigator	OTSUKA Makoto Medical Institute of Bioregulation Kyushu Univ., Associate Professor, 生体防御医学研究所, 助教授 (60203840)
Co-Investigator(Kenkyū-buntansha)	HATAKENAKA Masamitsu Medical Institute of Bioregulation Kyushu Univ., Research Associate, 生体防御医学研究所, 助手 (40253413)
Project Period (FY)	1998 – 1999
Project Status	Completed (Fiscal Year 1999)
Budget Amount *help	¥3,200,000 (Direct Cost: ¥3,200,000) Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000) Fiscal Year 1998: ¥1,700,000 (Direct Cost: ¥1,700,000)
Keywords	radiation damage / late effect / mouse kidney / cell proliferation / c-myc / c-fos / BUN
Research Abstract	We have previously described the increased proliferation and appearance of abnormally large nuclei in renal proximal tubule cells after radiation. A model has been proposed that the large nuclear cells might be dying and the increased proliferation might lead to mitotic death of these cells and cause functional damage. We measured the expression of c-fos and c-myc taking the ratio of densities of bands for irradiated portion to unirradiated portion of the kidney after RT-PCR procedure, and found the c-fos and c-myc expression increased very early (24 hours) after irradiation, probably representing increased DNA synthesis. The incidence of high c-myc expression increased according to radiation dose from 9 to 15 Gy. Then we measured the c-fos and c-myc expression 24 hours after 12 Gy irradiation, and followed BUN values representing the renal function of irradiated and right nephrectomized mice for 9 months after irradiation. Most of c-fos and c-myc positive mice showed increased BUN level, while all mice with negative c-fos and c-myc showed no BUN change. Measuring c-fos and c-myc expression seems to be a potential very early indicator of late radiation damage of kidney.