【Abstract】ObjectiveTo investigate the effect of xenotransplantation of microencapsulated rabbit parathyroid tissue in different sites in rats for the treatment of hypoparathyroidism. MethodsThe parathyroid glands from Wistar rats were removed to make them aparathyroid. Ultimately, sixteen rats were included because their serum calcium values were continuously below 1.6 mmol/L. We also encapsulated the cultured rabbit parathyroid tissue with alginateBaCl2 microcapsule. According to the transplantation sites, rats were randomly divided into two groups: renal adipose microcapsule group and peritoneal microcapsule group, eight in each group. Encapsulated rabbit parathyroid tissues were then transplanted accordingly to different microcapsule groups. The calcium serum contents were examined on 5，15，25，35，45，55 and 65 d respectively after transplantation and the grafts were observed through electron microscope on the 65 d in particular. ResultsThe calcium contents after transplantation in renal adipose microcapsule group restored to normal and the observation outcomes of grafts showed that they survived well. The calcium contents of posttransplantation in peritoneal group also restored to normal with an exception that it dropped to a level lower than 1.6 mmol/L on the 65 d. Electron microscope also showed that there were necrotic tissues in the center and only a few cells survived on the edge of the grafts. Within peritoneal microcapsule group, the values were significantly lower than others taken at different phases. ConclusionMicroencapsulated rabbit parathyroid tissue that was xenotransplanted into rats can survive and function without administration of immunodepressant. There are significant differences of calcium contents at varying phases between two transplantation sites, which demonstrate that renal adipose may be an optimal site for microcapsule xenotransplantation.