Liquid Nitrogen Of Cryopreserved Valved Aortic Organizational Structure Of The Same Species

Objective To search for the optimal cryoprotectant of aortic valve homografts among 3 different protectants Through observing the change of tissue structures of aortic valve homografts preserved by liquid nitrogen.Methods Three different cryoprotectants were used in the three groups:0.1mol·L DMSO in the control group,0.1mol·L-1 trehalose in test group 1, and 0.1mol·L DMSO with 0.1mol·L-1 trehalose in test group 2. Morphological observation was carried out with light and immunohistochemistry and electron microscopes on the fresh tissues and aortic valves preserved by liquid nitrogen for 6,9, and 12 months, respectively.Results More tissue structures were destroyed with the increase of the storage periods. Under the light microscope and immunohistochemistry, the structures of the three groups were all different from that the fresh tissues(d=17.08-30,P<0.001), and the differences among the three groups were significant (d=6-13,P<0.01,0.05). Under the electron microscope, the ultrastructure of aortic valve homografts changed obviously in the control group, less obviously in test group 1, and least obviously in test group 2.Conclusion Trehalose is effective in the protection of aortic valves preserved by liquid nitrogen.The effect of 0.1mol·L-1 trehalose is better than that of 0.1mol·L DMSO. The combination of 0.1mol·L-1 trehalose and 0.1mol·L DMSO has a significantly better effect than the separate use of either of them.