The effect of freeze rate, duration of phase transition, and warming rate on survival of frozen canine kidneys

Abstract

The effect of cooling rate, warming rate, and duration of phase transition upon survival of frozen canine kidneys was investigated. In the present study, 11 kidneys out of 14 rapidly cooled (2–4 °C/min) to −22 °C and thawed (70–110 °C/min) were viable following contralateral nephrectomy. The serum creatinine and BUN levels rose to a maximum of 8.4 and 30 mg%, respectively, on the eighth day post-contralateral nephrectomy. Average survival time was 10 days; however, two of the dogs in this group were allowed to survive, one for 3 months and one for over 2 years. Eight kidneys out of 16 slowly cooled (0.25–1.0 °C/min) and either rapidly or slowly warmed (20–30 °C/min) had function to produce small amounts of urine; however, they did not survive more than 5 days after contralateral nephrectomy. Cooling rates of 0.1 and 10 °C/min were too harmful to the kidney to have renal function after reimplantation. The minimum renal cell damage as assessed by LDH and GOT in the post-freeze perfusate was found in the 2–4 °C/min cooling rate following rapid warming (70 °–110 °C/min). Correlation of the duration of phase transition time to renal cell damage was linear for LDH and GOT ( r = 0.93). This result suggests that the duration of phase transition time also is an important factor during the freezing process, affecting postthaw survival of canine kidneys.