An extraperitoneal isolated vascularized bone marrow transplant model in the rat.

An isolated vascularized bone marrow transplant (iVBMT) model was previously developed in the rat to specifically study the role of bone marrow and its environment in a composite tissue allotransplant. An extraperitoneal model was successfully created to avoid laparotomy and cross-clamping of the great vessels. The extraperitoneal iVBMT model consisted of a left donor femur that was harvested with its nutrient vessels, anastomosed to the right femoral vessels in a syngeneic host, and then placed subcutaneously in the abdominal wall. At explant, the graft vessels were grossly patent, and histology of the graft bones showed a viable marrow compartment. Polymerase chain reaction demonstrated peripheral chimerism in the recipients. This model is technically simple with minimal morbidity in the recipient animals. By using the iVBMT, future studies across semiallogeneic and allogeneic barriers will help define the role of the bone marrow compartment in composite tissue allotransplants to potentially induce immune tolerance.