| Objective: To investigate the influence of cryopreservation on the cellular viability of late-pregnancy fetal valved aortic allografts and preliminary evaluate the preserved efficacy of fetal heart valves and large vascular allografts storaged in liquid nitrogen.Methods: Twelve aortic allografts were sterilely procured from fetuses whose gestational ages ranged from 20 to 40 weeks within 12 hours after brained death. Each sample was bisected into control group and study group.The cellular viability of control group was directly tested and that of study group was examined after being storaged in liquid nitrogen for a week through a programmed frozen procedure. There were three methods to determine cellular viability of fetal aortic allografts ,which were trypan blue stain , tissue culture and Methylthiazol tetrazolium assay (MTT assay). The viable cells were identified by immunohistochemistry and light microscopy.Results: Viable cells might derived from both group. The cell survival rate of fetal aortic allografts was (86.4% ±0.8% )in control group and was (79.4% ±0.8% )in study group showed by trypan blue stain, the difference between them had statistically significance (t=15.825,P<0.001) . The cellular OD valve of control was (0.442 ± 0.046) and that of study was(0.424 ± 0.041)measured by MTT assay ,the difference between them failed to statistically significance(t=1.617,P>0.05). Most cells showed spindles triangle and star morphologic appearance. Some cells developed into overlapping layers of parallel, typically liking "peak and valley" . There were both positive and negative stained cells with the monoclonal antibody of mice anti-human smooth muscle a-actin proteins.Conclusions: There were viable cells in the late-pregnancy fetal aortic allografts after being storaged in the liquid nitrogen. Cryopreservation might harm the cellular viability but had little effect on the cellular proliferative capacity . This study provided the theoretical... |
PDF Full Text Request