Experimental Study On Long Term Preservation Of Vital Cartilages In Vitro And The Utility Of Them

The preservation of vital cartilage is an important factor in the plastic surgery. Surgical treatments for cancer of the larynx , including radical resection , are well documented. Increased attention is now being given to reconstructive surgery to restore laryngeal function. Partial or total substitution of the laryngeal architecture with homologous cartilage seems to be good for laryngeal reconstruction after total or subtotal laryngectomy. Theuse of allogeneic cartilage guarantees to retain the laryngeal lumen have many advantages ,without necrosis or an immune reaction .But the repair of cartilage defects with autografts is still a problem in reconstructive surgery. Such as in many cases the possibility of a delayed or late cartilage grafting procedure or multistage reconstruction is necessary . The cartilage storage with preservation of its viability would be usefull. There are different preservation methods that have been used , with varied success. But the use of chemical preservation procedures such as formaldehyde , Merthiolate and cialit can be led to a loss of viability of the grafts. In our previous experiment we have studied the possibility of vital allogeneic cartilage preservation using tissue culture method. We found that cartilage grafts can be preserved for 30days by using tissue culture method without lossing their viability. The viable allografts stored in tissue culture medium can successfully repaired the defects of thyroid cartilage. Neverthless our tissue-culturedcartilage is not so big and the preservation time is not very long. And we do not know whether cartilage with perichondrium and human catilage can be stored for a long time by using tissue culture method.The aim of this experiment is to study the possibility of long term preservation of big vital cartilage using tissue culture method, and effect of the cartilage after being transplanted. New Zealand white rabbits's thyroid cartilage, rib cartilage with or without perichondrium, human rib and nasoseptal cartilage with or without perichondrium were collected. The cartilage samples were cut into 5mm 2mm 1 mm and 25mm 20mm 2mm fragments. The fragments were preserved in the RPMI-1640 medium. The viability of the cartilage grafts were observed after 5 days, 10days, 20days, 30days, 60days, 90days, 120days, 150days and 1 80days, using microscope and trypan blue dye exclusion test. We found that Cartilage grafts preserved in the RPMI-1640mediumretained its viability during the whole 180 days storage time. Moreover, we also have studied the effect of transplantation using tissue-cultured vital allogeneic and heterogeneous cartilage grafts. In one way, autologous catilage, allogeneic fresh and preserved cartilage with or without perichondrium, preserved human cartilage with or without perichondrium were implanted in the back subcataneous of the same rabbit. Follow-up examinations were performed at 7s 30s 60s 90s 120s 150s 180s 200 s 300 and 370days. At each time point , samples were taken out and the transplanted effect were observed. In the other way, tissue-cultured human cartilage were used for clinical treatment. We found that allogeneic fresh and preserved cartilage grafts with or without perichondrium were well accepted and showed no evidence of immune cell infiltrations. The human preserved cartilage grafts with perichondrium were preferable to grafts without perichondrium. Our results demonstrated that human and rabbit cartilage grafts canbe successfully preserved in vitrol for long time using tissue culture method, without lossing their viability. The viable allografts stored in tissue culture medium are advantageous for clinical use. The human preserved cartilage grafts with perichondrium were preferable to grafts without perichondrium.