Interaction of cisplatin and x-rays in rat kidney.

Cisplatin was administered as a single iv dose of 5 mg/kg in WAG/Rij female rats at intervals of 7 days or 30 minutes before or 7 days after graded irradiation of the left kidney. The unirradiated right kidney was removed 4 weeks after the x-ray treatment. Kidney function was determined by measuring urine osmolality and plasma urea. The kidney function parameters did not change measurably in animals treated with cisplatin alone. Only differences in urine osmolality were observed between the groups that received combined treatment or irradiation only. Long-term renal fibrosis was assessed by measuring the hydroxyproline content. Significant increases in renal hydroxyproline content were observed in animals receiving treatment with cisplatin either 7 days before or 7 days after irradiation, compared with animals receiving irradiation alone.