Successful parathyroid gland autotransplantation in the rat using a simplified cryopreservation technique.

In the present work a simplified technique for cryopreservation of parathyroid glands was compared to the generally used technique needing a programmed freezer. Four groups of rats had total parathyroidectomy. In two of them the glands were cryopreserved and reimplanted 10 days after ablation. The other two groups had, respectively, immediate parathyroid autotransplantation and no autotransplantation. During a follow-up of 60 days, plasma calcium remained low and plasma phosphorus elevated in all aparathyroid rats of the last group. In the group of rats with immediate parathyroid reimplantation, both mean plasma calcium and phosphorus values rapidly returned to the normal values observed before operation. In the rats that had the simplified parathyroid cryopreservation technique, mean plasma phosphorus also returned to the normal range and mean plasma calcium to nearly normal. However, in the group of rats with the classical cryopreservation method, the mean plasma calcium and phosphorus levels remained far from normal in the majority of animals. It was concluded that parathyroid glands of the rat could be successfully autografted after previous freezing using a simplified cryopreservation technique. The results obtained were comparable with, even though not as perfect as, that observed after immediate autotransplantation. If suitable for human parathyroid gland fragments, this technique would allow a more general application of parathyroid tissue cryopreservation.