Protective effect of chondroitin sulfate on homograft aortic valve cryopreserved in liquid nitrogen

Objective To investigate the protective effect and the mechanism of chondrointin sulfate(CS) on cryopreserved homograft aortic valve in liquid nitrogen.Methods Fourty-eight rabbit aortic valves were randomly divided into 6 groups(n=8).Eight fresh valves were included in fresh group,the other 40 valves were cryopreserved in liquid nitrogen.Cryoprotectant for control group was 10%(volume) dimethyl sulfoxide(DMSO),while cryoprotectant for experiment groups(Ⅰ～Ⅳ) contained different volume of CS(2.5%,5%,7.5%,10%)with 10% DMSO,respectively.The survival rates of control group and experiment groups in 24 hours were examined and the specimens were observed under light and electron microscopes.Results Cryopreserved valves had the highest endothelial cell survival rates and the slightest morphologic change when 7.5% CS was presented with 10% DMSO.Conclusion CS has protective effect on cryopreserved aortic valve in liquid nitrion,and the effect relates with the concentration of CS.The cryoprotectant with 7.5% CS shows the best effect.