A comparison between cyclosporin A and methylprednisolone plus azathioprine on bronchial healing following canine lung autotransplantation.

The effects of two low-dose immunosuppressive therapies upon the healing of the bronchial anastomosis and skin wounds following lung autotransplantation were evaluated. Autotransplantation was performed in three groups of dogs: Group 1 (nine dogs) received no immunosuppression, Group 2 (seven dogs) received postoperative immunosuppression with methylprednisolone (2 mg/kg) and azathioprine (1.5 mg/kg), and Group 3 (four dogs) received postoperative immunosuppression with cyclosporin A (20 mg/kg/day). Skin incisions 7 cm in length were made in the dorsal region of each dog. Dogs were put to death 23 days postoperatively, and the breaking strength of the bronchial anastomoses and skin wounds was evaluated with the Instron Universal Testing Machine, with a cross-head speed of 0.5 cm/min. Bronchial breaking strengths were similar in Groups 1 and 3 and significantly higher than in Group 2 (p less than 0.001). Skin breaking strengths were similar in Groups 1 and 3 and significantly higher than in Group 2 (p less than 0.001). Scanning electron microscopic (SEM) studies of both skin and bronchial wounds showed normal formation of collagen bundles in Groups 1 and 3 but a disorganized pattern in Group 2. Our results suggest that low-dose immunosuppression with methylprednisolone and azathioprine significantly affects wound healing and breaking strength of both bronchial anastomoses and healed skin incisions following canine lung autotransplantation. Immunosuppression with cyclosporin A had no adverse effect on either bronchial or skin healing.