[Histologic studies on canine lung transplantation]

Histologic and functional investigation on lung allotransplantation was performed in 26 mongrel dogs divided into major two groups. In Group A left lung allotransplantation was carried out. These dogs were followed by administration of Cyclosporin A and Azathioprine. In dogs of Group B left lung allotransplantation and postoperative measurement of pulmonary artery (PA) pressure by contralateral PA occlusion test using modified Swan-Ganz catheter were performed. This group was subdivided into 4 groups; Group B-I: 6 hours preservation of donor's lung and administration of Cyclosporin A and Azathioprine. Group B-II: no preservation of donor's lung and administration of Cyclosporin A and Azathioprine. Group B-III: Group B-II + steroid and Group B-IV: Group B-I + steroid. In many dogs the prolongation of occurrence of acute rejection was observed Cyclosporin A. In Group A the fibrotic changes around the blood vessel and/or bronchus were detected occasionally. The appearance and desquamation of atypical type II cells were present in a few dogs. In Group B the characteristic features of acute rejection were observed. Histologic differences between groups of immediate transplantation (B-II & III) and groups with preserved lung for 6 hours (B-I & IV) were not demonstrated. There was no definite case of so-called "alveolar rejection". The mean-PA pressure of Group B rose up just after the transplantation in every dog. On postoperative 7th day the PA pressure after the right PA occlusion decreased, however it elevated again on 14th day except one dog, because of the diffuse mononuclear cell cuffing around blood vessel walls. We believe that this test is an useful examination for the evaluation of occurrence and intensity of rejection.