Autotransplantation of adrenal cortical tissue: a rodent model

Autotransplantation of human adrenal tissue has been attempted often, but results have been difficult to evaluate and success has been infrequent. Factors that may affect success include: volume of transplanted tissue, recipient site, inclusion of cortical capsule with the autograft, systemic or local growth factors, and the timing of evaluation. We have evaluated a model of autotransplantation in rats that will permit examination of these factors. Male Sprague-Dawley rats were assigned to (1) bilateral adrenalectomy (ADX), (2) bilateral adrenalectomy with immediate autotransplantation to a flank muscle pocket of one third of a single adrenal gland with its capsule attached (TX), or (3) sham operation. Animals were provided with 0.9% saline solution ad lib. At 2, 4, 6, and 12 weeks after surgery animals were stressed by brief exposure to ether and 15 minutes later had blood collected for determination of corticosterone concentration (C). ADX animals consistently weighed less than either TX or sham-operated animals; weights of sham-operated and TX animals were similar. Sham-operated animals uniformly had C levels higher than ADX or TX animals. At 2 and 4 weeks after surgery, C was similar in ADX and TX; but at 6 and 12 weeks, TX animals had higher values than had ADX animals. With this model, graft function can be demonstrated at 2 weeks by comparing body weight and at 6 weeks by comparing postether levels of C in TX animals to ADX animals. ADX animals can be maintained without steroid replacement on a regular diet with 0.9% saline solution ad lib. This model will permit examination of technical and physiologic influences on transplant success with both fresh and cryopreserved tissue and may lend itself to radionuclide or nuclear magnetic resonance assessment of graft function.