The irradiation is said to have immuno-suppressive effect on the allograft and so its effect on the regenerating pattern of the marrow structure following homograft was studied.
In normal rabbit the resection of lcm long radius was substituted with a homologous radius of same length after 2, DOOR irradiation of 1E4Cs and the graft was immobilized for three weeks with 3cm long intramedullary I~-wire fixation.
For ten weeks period after removal of the wire, histological changes of the local medullary cavity were compared with the results obtained with those of autogenous and the homologous graft groups.
1. The autograft(Aj group showed that the initial aggregate of the blood clot, the necrotizing tissue, and the inflammatory cellular infiltration almost disappeared at five weeks, and then the cavity was gradually replaced by the fibrous tissue, the fat cells, the new vessels, and the traboculae, regaining the normal marrow structure after seven or ten weeks.
2. In the fresh homologous graft(H) group, the cellular infiltration was much pronounced and prolonged, up to five of seven weeks. Besides the fat cells, the marrow contained the macrophages, the osteoblasts, and the osteoclasts between three and five weeks, and at ten weeks the regeneration of the marrow was incomplete yet. -
3. The 2, 000 R-irradiated homograft(R) group had, except the less intensive inflammatory cell infiltration, the changes similar to that of the H-group for five´weeks. The local medullary cavity, however, was subsequently repalced by proliferation of the fibous tissue, the developing blood vessels, the fat cells and the osteoblasts. At ten weeks the restitution of the marrow was nearly complete.
4. It fellows from the above results that the restitution of the local marrow structure after the homologous graft, when irradiated with 2, 000 R of "´Cs, was prompted favorably and showed histological changes similar to those of the sutograft group at ten weeks.
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