PROLONGED SURVIVAL OF MURINE THYROID ALLOGRAFTS AFTER 7 DAYS OF HYPERBARIC ORGAN CULTURE IN THE UW PRESERVATION SOLUTION AT HYPOTHERMIA

Abstract

Organ culture of murine thyroid allografts in hyperbaric oxygen (95% O2 at 25 psi, 37 degrees C) for 48 hr, results in prolonged allograft survival. Endocrine tissues can be cultured at 37 degrees C--however, this method may not be applicable to vascularized organs at normothermia. The aim of this study was to apply hyperbaric oxygen culture (HOC) under organ preservation conditions (hypothermia, UW solution) that have been shown to be successful in clinical organ transplantation. B10BR/SGSNJ murine thyroid lobes were transplanted beneath the kidney capsule of C57BL/10J recipients. Thyroids were cultured in Eagle's MEM at 37 degrees C (controls) and at 5 degrees C, under hyperbaric conditions (95% O2:5% CO2, 25 psi). Alternatively, thyroids were cultured in UW solution (+/- allopurinol/GSH) at 5 degrees C, for up to 7 days. Graft survival was determined 21 days posttransplant by 125I uptake and by histology. In Eagle's MEM, HOC at 37 degrees C/48 hr and 5 degrees C/7 days, resulted in 93% and 20% allograft survivals, respectively. In UW solution (- allopurinol/glutathione [GSH]), HOC at 5 degrees C/7 days resulted in 83% allograft survival: immunoperoxidase staining showed a decrease of MHC class I alloantigen expression. Oxygen free radical scavenger (allopurinol/GSH) addition to the UW solution diminished this effect and suggested an oxygen free radical-mediated mechanism in immunoalteration. These results demonstrate that HOC for 7 days reduced the antigenicity and immunogenicity of murine thyroid grafts under conditions that simulate organ preservation. Hypothermic hyperbaric oxygen culture conditions require testing in a higher animal species and in vascularized grafts to determine if this method can be applied to whole-organ transplantation.