Repopulation of donor cells from the recipient following extremity graft: studies using the LACZ transgenic rat

Cell traffic from the recipient into the graft, so called graft chimerism, appears to play a major role in graft acceptance. This study was conducted using LacZ transgenic rats to define recipient cell migration into whole-limb grafts. Eighteen hind limb transplants were performed across LacZ+ transgenic and LacZ- rats. LacZ expression was evaluated by X-gal staining. Intense LacZ expression was observed at the interfollicular epidermis in the skin component of LacZ- limb grafts 48 weeks after transplant. Muscle fibers and cartilage showed intense LacZ expression in LacZ+ limb grafts at 48 weeks but no expression in LacZ- grafts. Polymerase chain reaction studies confirmed the presence of the LacZ gene in the bone and skin of LacZ- limb grafts and in the muscle of LacZ+ grafts. Our results demonstrate that there is a gradual increase in repopulation of recipient cells in grafted skin and bone tissues, but muscle and cartilage tissues retain donor cell origin.