Kidney radioprotection by temporary hypoxia. Experiments with degradable microspheres.

Deep hypoxia protects biological tissue against ionizing radiation. By intra-arterial injection of degradable starch microspheres the renal circulation was temporarily blocked in unilaterally nephrectomized rats. The induced hypoxia was utilized for protection of the kidney against single doses of high-voltage X-rays. Renal function and survival date were compared between animals protected by hypoxia and non-protected animals. The survival rate of the former animals exceeded that of the latter by a factor of 1.6. All irradiated animals showed a lower glomerular filtration rate, Hippuran clearance and urine osmolarity than non-irradiated controls. Surviving, protected animals irradiated with 42 Gy and 52 Gy showed a glomerular filtration rate of about 0.5 ml/min and a Hippuran clearance of about 2 ml/min, whereas all non-protected animals irradiated with 42 Gy died.