Experimental studies of lyophilized cartilage.

A lyophilized auricular cartilage graft and fresh auricular cartilage graft with sizes of 5×5mm and 5×10mm were homotransplanted into the subcutaneous tissue of the back, muscle of spinal erection and auricular portion of immature rabbits. Daily observation was executed about histological and histochemical changes of the rise and fall of grafts.The results are as follows:1) Lyophilized auricular cartilage grafts and fresh auricular cartilage grafts existed in the subcutaneous tissue, muscle and auricular portion for the 48-week observation period without being absorbed.2) Cartilage cell proliferation and cartilage graft growth were observed in the fresh auricular cartilage but were not observed in the lyophilized auricular cartilage.3) In the transplantation into the subcutaneous tissue, both lyophilized auricular cartilage and fresh auricular cartilage were covered with the fibrous connective tissue that differ from the subcutaneous tissue.4) In the transplantation into the muscle, both lyophilized auricular cartilage and fresh auricular cartilage were covered with the muscular tissue and the grafts had affinity with the recipient tissue.5) In the transplantation into the auricular portion, the new cartilage tissue was regenerated in the gap between the lyophilized auricular cartilage and the host cartilage, and between the fresh auricular cartilage and the host cartilage. The cartilage graft and the host cartilage were found to be joined by newly formed cartilage tissues. Newly formed cartilage tissues had no influence on the cartilage grafts.6) The changes in sizes of the grafts show no difference in both the lyophilized auricular cartilage and fresh auricular cartilage.