Studies of renal preservation using a rat kidney transplant model. Evaluation of citrate flushing.

Rat kidneys were flushed with isotonic citrate solution, hypertonic citrate solution, or Collins's C2 solution, and were stored hypothermically for 24 hr before transplantation into another rat of the same inbred colony. The number of animals surviving for one month was greatest with isotonic-citrate-flushed kidneys (82%), and least with Collins's C2 solution (27%). Functional and morphological damage after transplantation was consistently greater in Collins's-flushed grafts, as compared with citrate-flushed grafts. Best results were attained with the isotonic-citrate flushed grafts. Seven days after contralateral nephrectomy all surviving animals had elevated serum creatinine and urea concentrations, along with decreased creatinine clearance, and they had secreted large volumes of dilute urine. Renal function was best in animals with isotonic-citrate-flushed grafts. After one month, significant improvement in urine osmolality, creatinine clearance, and serum creatinine had occurred only in the rats with citrate-flushed grafts. There were no significant differences between the citrate groups. All surviving rats had some residual renal cortical damage, but severe interstitial nephritis (greater than 30%) was much less frequent in the citrate groups.