Nerve regenerating effect of short-course administration of cyclosporine after fresh peripheral nerve allotransplantation in the rat: comparison of nerve regeneration using different forms of donor nerve allografts.

There is almost universal agreement that if cyclosporine (CsA), which is a potent immunosuppressant, is temporarily administered after surgery, regenerated axons will be maintained even after withdrawal of CsA following peripheral nerve allotransplantation. Thus, this experimental study was conducted to investigate whether a difference in donor nerve form, including thickness and length, influences nerve regeneration after withdrawal of immunosuppression with CsA. The findings suggest that as a result of immunosuppression with CsA, large-diameter nerve grafts are better able to induce nerve regeneration than small-diameter grafts, and after withdrawal of the immunosuppressant, thick nerve grafts are also better able to preserve regenerated axons against the rejection reaction than thin grafts. With regard to the length of the grafted nerve, short nerve allografts yield higher axon counts than long ones, the same as with autografts. The best way to induce nerve regeneration appears to be to transplant a short, thick nerve allograft, which is definitely capable of inducing many regenerated axons.