Repopulation of donor cells from the recipient following extremity graft: Studies using the L AC Z 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. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.