ABSTRACT
Objective To investigate the feasibility and practicability of the precondition using high-dose of Tacrolimus (FK506) before the bone marrow transplantation (BMT) for macrochimerism specific tolerance. Methods One hundred male C57BL/6 mice and 60 female BALB/C mice were respectively used as donors and recipients of skin transplantation, and another 15 male ICR mice were used as the third germ line to detect the specificity of tolerance. Sixty recipient mice were divided randomly into 5 groups: blank control group, FK506 group, BMT group, experimental group (FK506+BMT) and third party donor control group, with 12 mice in each group. Before the skin transplantation, high-dose abdominal injection of FK506 (3 mg/kg?2 d) was performed in recipient mice. On the transplantation day a bonus of 2?10 7 bone marrow cells were injected through the tail vein. Then a short period of low-dose FK506 (0.5 mg/kg?7 d) was administrated for maintenance treatment. The survival time of skin grafts, reject reaction against the third party skin, and mixed lymphocyte culture (MLC) were observed. The polymerase chain reaction (PCR) was employed for the detection of macrochimerism. Results Routine dose of bone marrow cells infusion or short period of FK506 administration led to neither prolonged survival time of grafts nor the formation of macrochimerism. The skin graft survival time was significantly prolonged in the experimental group (24 0?1 5 d), as compared with the blank control group (9 6?1 1 d), the FK506 group (10 5?1 6 d), the BMT group (10 3?1 5 d), and the third party donor control group (9 8?1 1 d), respectively ( P