[Electron microscopic investigation following canine pulmonary transplantation with regard to functional effects...

The function of alveolar macrophages in correlation with immunological stimulation, consequently also in pulmonary transplantation, are a subject of discussion. In this study the alveolar manifestations of rejection following pulmonary transplantation, are a subject of discussion. In this study the alveolar manifestations of rejection following pulmonary homotransplantation are investigated by electron microscopy.

In 20 healthy dogs (body weight between 7 and 19 kg) a left side pulmonary homotransplantation was performed using a standardized method. 2 randomized groups of 10 animals each were formed, one undergoing immunosuppressive therapy, the other none. Needle biopsies (Menghini needles) were taken in both groups at the onset of rejection daily until death of the animals (on the 5th to 12th postoperative day). At death of the animals always total rejection of the homograft was observed. The other animals were subjected to a scheduled immunosuppressive therapy (KREUZER et al. 1973, RADASZKIEWICZ et al. 1974). Needle biopsies were taken only at the stage of a clinically or roentgenologically ascertained crisis of rejection. Before implantation of the homograft and 20 mins after occlusion of anastomoses and onset of circulation in the transplant biopsies were taken, too, to exclude early changes or alterations in the donor. The lung specimens 2 mm in size) obtained by biopsy were fixed in phosphate buffered OSO4 and buffered phosphate solution by usual alcohol series. After embedding in epon the specimens were studied by electron microscopy.

In the group not undergoing immunosuppressive therapy beginning with the 3rd post-operative day perivascular lymphocytic and plasmacellular infiltrates were seen which increased during the course of rejection. In both groups a swelling and vacuolization of endoplasmatic reticulum, cytoplasmic microvilli with bridge formation accompanied by an increase of alveolar macrophages and by augmentation of lamellar bodies in granular pneumocytes were noted following operation. A correlation between the increase of lamellar bodies and increase of surfactant has been shown previously.