To develop the surgical model, composite mandibular tissue was transplanted at the same site. Revascularization was accomplished by end-to-end anastomosis of the facial vessels using standard microvascular techniques. A total of 33 vascularized composite mandibular tissue allografts were similarly performed between two incompatible strains of rabbit. In a control group of 9 animals, no immunosuppression was administered. All of these allografts were rejected acutely within 10 days after surgery. 7 allograft recipients were immunosuppressed with azathioprine and prednisone at 5 mg/kg.d and 2 mg/ kg.d, respectively. Their allografts were also rejected acutely within 10 days. 17 allograft recipients were immunosuppressed with cyclosporine A (CsA). All allografts showed primary wound healing and hair growth and took on normal appearance. 8 of these recipients were given CsA at 5 mg/kg.d i.v. and their allografts were rejected at a mean time of 17.9 days. The remaining 9 recipients given CsA at 10 mg/kg.d i.v. rejected their allografts at a mean time of 36.1 days. In 3 of them, the rejection was reversed with CsA (20 mg/kg.d) injection for five days successfully, and one allograft survived more than 100 days. This pilot study suggests that the surgical model is reliable and that CsA will be useful as an immunosuppressive agent in the study of vascularized composite mandibular tissue allografts.
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