Degenerative and regenerative phenomena in brain heterotopic homoplastic transplants of adult Triturus carnifex (Urodele Amphibians).
The brains of adult Urodele Amphibians (Triturus carnifex Laur.) were homoplastically transplanted in conditions of complete morpho-functional isolation. Despite the heterogeneous nature of the histological aspects observed, the results point to the following general pattern for the fate of the brain transplants: 1) rooting phase (about day 5 after the operation) as indicated by degenerative patterns affecting the various encephalic districts and mainly involving the more peripheral neurons and the nerve fibers, and to a lesser extent the periventricular gray and the ependyma; 2) phase of rejection by host (from day 10 until end of experiment on day 30) as indicated by lymphocytic infiltration, the presence of macrophages and pyknoses, and the formation of a connective tissue capsule surrounding the transplant; 3) regenerative phase (from about day 10) as indicated by the onset of mitotic activity affecting elements of the ependymal epithelium and the periventricular gray, particularly in the telencephalic district. By the end of the experiment, in most of the transplants examined, degenerative processes were found to have prevailed over the regenerative phenomena. However, in some cases, and particularly in one of them, a distinctly higher degree of structural organization of neurons and nerve fibers can be observed at the telencephalic level. It may be postulated that, whenever a greater degree of compatibility exists between the host and the transplanted organ, it is possible, even in conditions of complete morpho-functional isolation, for the brain to express regenerative power through the ependyma and the matrix zones which have already been identified by some Authors in telencephalic periventricular areas or scattered through the mesencephalic gray matter.
Margotta
V
V
Dipartimento di Biologia animale e dell'Uomo (Facoltà di Scienze), Università di Roma La Sapienza, Italy.
Filoni
S
S
Del Vecchio
P
P
D000818:Animals; D001921:Brain / Q000166:cytology; D016380:Brain Tissue Transplantation / Q000473:pathology / Q000502:physiology*; D009410:Nerve Degeneration; D009416:Nerve Regeneration; D013997:Time Factors; D014184:Transplantation, Homologous; D014319:Triturus