Morphology and immunohistochemistry of rat aortic grafts

• Published in: Folia microbiologica 1999-01, Vol.44 (3), p.339-353
• Main Authors: ROSSMANN, P, LACHA, J, LODEREROVA, A
• Format: Article
• Language: English
• Subjects: Actin; Animals; Antigens; Aorta; Aorta, Abdominal - pathology; Aorta, Abdominal - transplantation; Autografts; Biological and medical sciences; Bone grafts; Calcification; CD4 antigen; CD8 antigen; Cell proliferation; Connective tissues; Cyclosporin A; Cytoskeleton; Cytotoxicity; Depletion; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Grafting; Immunohistochemistry; Immunosuppression; Infiltration; Intervals; Leukocyte migration; Light microscopy; Lipids; Lymphocytes; Macrophages; Male; Morphology; Muscle, Smooth, Vascular - pathology; Muscles; Optical microscopy; Proteins; Proteoglycans; Rats; Rats, Inbred Lew; Smooth muscle; Syngeneic grafts; Thickening; Thickness; Thromboembolism; Thrombosis; Tissue, organ and graft immunology; Transplantation; Transplantation, Homologous; Transplantation, Isogeneic
• ISSN: 0015-5632; 1874-9356
• DOI: 10.1007/BF02818558

Allotransplantation (TPL) of the abdominal aortic segments of BN donors was performed in 32 Lewis recipients with or without cyclosporin A (CyA) immunosuppression, and the vascular changes were compared to those of 10 syngeneic grafts (Lewis-->Lewis) and to the autologous rat aortae. The vessels were examined 2, 3, 4 and 5 months post TPL by light microscopy, the thickness of intima and media was measured morphometrically and the cell infiltration of adventitia and intima was assessed semiquantitatively. Thirty-six aortae were examined by three-step enzyme immunohistochemistry (proof of selected differentiation, proliferation, cytoskeletal and connective tissue matrix antigens). The adventitia displayed an intense focal and scattered mononuclear cell infiltration; it was more discrete and focal in the intima. This cellularity persisted in the allografts but disappeared from the intima and was reduced in the adventitia of the isografts after four and five months. Disseminated ED1+ activated macrophages were the most prominent population of infiltrates whereas modest numbers of adventitial ED2+ tissue macrophages remained constant throughout the intervals examined. CD4+ cells (focal and scattered) outnumbered (roughly twice) the scattered CD8+ lymphocytes; both these types were rare in the intima. Leukocyte invasion of the media was lacking (except for scarce isolated CD8+ cells in some allografts). In syngeneic grafts the smooth muscle cells (SMC) of media remained intact and the intimal thickening was slight to absent (about 5 microns) four and five months post TPL. On the other hand, the allograft media underwent severe destructive changes (karyolysis, depletion of alpha-SMC actin, focal calcification and general thinning without rupture or aneurysm). The prominent allograft intimal thickening (70-80 microns) was due to the proliferation of longitudinally oriented myointimal cells (alpha-SMC actin, FD2, PCNA and Ki67+) and an increase in matrix substance (strong metachromasia and positivity of chondroitin-sulfate proteoglycan). The deposition of lipids remained discrete, without atheromatous plaques and mural thrombosis. All changes were comparable in CyA-treated and untreated animals. Thus the main lesions of the allografts were (i) persistent mononuclear infiltration chiefly in adventitia, (ii) destruction of medial SMC, and (iii) intimal thickening by proliferation of myointimal cells. At the postTPL intervals examined the proliferation and intimal mig