Expression of the c-myc and c-fos genes as a potential indicator of late radiation damage to the kidney.

Abstract

To evaluate proliferative response according to c-myc and c-fos gene expression as an early indicator of late radiation damage to the kidney. c-myc and c-fos gene expression was measured in the irradiated kidney of C3H/HeSlc mice using reverse transcriptase-polymerase chain reaction (RT-PCR) 24 h after 9, 12, and 15 Gy as well as 2 and 7 days after 15 Gy. In a second experiment, 12 Gy was administered to the right kidney plus the lower half of left kidney. The mice underwent left nephrectomy 24 h after, and the correlation between increased gene expression and elevation of the blood urea nitrogen (BUN) level representing late functional damage was investigated. c-myc and c-fos expression increased in 1 of 10 controls and in 8 of 10 and 7 of 10 mice that received 15 Gy, respectively. Expression increased dose-dependently from 9 to 15 Gy. In mice having an increased BUN level, 7 of 10 and 8 of 10 were positive for c-myc and c-fos, respectively. All 6 mice having an unchanged BUN level were negative for c-fos, while 5 were negative for c-myc. Measurement of c-myc and c-fos gene expression is potentially an early indicator of late radiation damage to the kidney.