[Experimental study on cryopreservation of arterial allografts by vitrification]

To evaluate the feasibility of preservation of arteries by vitrification and the effectiveness of vitrified arteries as allografts.

Sixty rabbits were used in the research. Forty-eight femoral arteries were harvested from 24 rabbits as the transplanted materials,and 24 femoral arteries were preserved by vitrification, 24 by freezing for 14 days, respectively. The other 36 rabbits were used as the transplanted subjects, and were divided into three groups, 12 rabbits including 24 femoral arteries per group: Group A (fresh arterial autografts), Group B (vitrified arterial allografts) and Group C (frozen arterial allografts). The morphologic changes of arterial grafts were observed macroscopically and histologically. The patent rate of arterial grafts were measured by angiography, and the rabbits were sacrificed on the 14th day, the 30th day, the 60th day and the 120th day after transplantation respectively. Arterial grafts were harvested to observe the morphological changes,and the immunological rejection was evaluated by measuring the ratio of tunica intima and tunica media. The results were compared between these groups.

Before transplantation, the integrated rate of Group B was 91.67%, which was significantly better than that of Group C (54. 17%, P < 0.01). After transplantation, the accumulative patent rate of Group B was 87.50%, which was significantly better than that of Group C (66.67, P < 0.05). There was statistically significant difference in the ratio of tunics intima and tunica media between Group B and Groups A, C(P < 0.05).

The above results show that vitrification does less damage to cells and tissues because of ice-free in the process of cryopreservation. So vitrification can be used to preserve arteries, and the arterial allografts preserved by vitrification are better than those preserved by freezing.