Residual radiation-induced damage to the kidney of the pig as assayed by retreatment.
The effect of re-irradiation on the previously irradiated kidney was studied in the Large White female pig. Both kidneys of 14-week-old pigs were initially irradiated with a single dose of 3-7 Gy of 250 kV X-rays. The individual kidney glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and the haematocrit (Hct) were serially measured up to 24 weeks after X-irradiation. Doses of 3 and 5 Gy of X-rays had little effect on the GFR. However, 7 Gy of X-rays caused a marked decline in the GFR up to 12 weeks after irradiation; the GFR then began to recover. A similar pattern of response was seen in the ERPF. In contrast, the Hct was reduced in all pigs 4 weeks after X-irradiation. The extent of the decline and subsequent recovery 24 weeks after irradiation appeared to be related to dose. Twenty-four weeks after X-irradiation both kidneys were re-irradiated with a single dose of 7.9 Gy of 60Co gamma-rays; both kidneys of four age-matched control pigs which had not previously received X-irradiation were similarly treated. Individual kidney GFR, ERPF and Hct were again serially measured up to 24 weeks after gamma-irradiation. Re-irradiation resulted in a significantly greater reduction in the GFR, ERPF and Hct compared with that seen after gamma-irradiation alone. Moreover, the severity of the reduction in the GFR and Hct observed after gamma-irradiation was related, in a dose-dependent manner, to the initial X-ray doses employed. These results indicate that the kidney fails to exhibit complete long-term recovery in function following irradiation. Re-irradiation of the kidney in patients should thus be viewed with extreme caution.
CRC Normal Tissue Radiobiology Research Group, Research Institute, University of Oxford, Churchill Hospital, UK.
M E
ME
Robbins
T
T
Bywaters
M
M
Rezvani
S J
SJ
Golding
J W
JW
Hopewell
D000818:Animals; D003037:Cobalt Radioisotopes; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects; D005919:Glomerular Filtration Rate / Q000528:radiation effects*; D006400:Hematocrit; D007668:Kidney / Q000528:radiation effects*; D007700:Kinetics; D051379:Mice; D011833:Radiation Injuries, Experimental / Q000503:physiopathology*; D012079:Renal Circulation / Q000528:radiation effects*; D013552:Swine; D014965:X-Rays / Q000009:adverse effects
D003037:Cobalt Radioisotopes