Improved survival after allogeneic small intestinal transplantation in the rat using cyclosporine immunosuppression.

We investigated the effect of cyclosporine on survival after intestinal transplantation between histoincompatible Brown Norway (AgB3/3) and Lewis (AgB1/1) rats. Intestinal grafts were primarily vascularized (by microsurgical techniques) and interposed isoperistaltically in the recipient's jejunum. All animals were weighed and observed daily. Survival of recipients given cyclosporine 20 mg/kg/d (112 +/- 92 days, n = 10) was significantly longer (P less than .02) than that of recipients given no drug (12 +/- 4 days, n = 8). Six out of ten cyclosporine-treated animals remained alive and well at the conclusion of the experiment. One of these was killed and showed no gross or microscopic evidence of rejection. The described experimental model involves a simple operative technique and minimal postoperative care and should permit systematic investigation of the detection and prevention of rejection.