The Study Of Safe Ischemic Time Of Endothelial Cells In Autologous Vein Graft

Objective: To investigate the injury degree of different ischemic time on dog endothelial cells ,to make certain the safe ischemic time of endothelial cells of autologous vein graft. Methods: The dog femoral vein was harvested and fixation at 0, 30, 60, 90min and were examined with HE, ET-1 , immunohistochemical stain, scanning and transmit electron microscopy. Dog model of vein graft of different ischemic times was established. The vein grafts(VG) were harvested at 1, 3. 7. 14 days after implantation and were examined with HE , immunohistochemical stain, apoptosis ratio of EC, scanning and transmit electron microscopy. The ultrastructure of the endothelial cells, the covering percentage of endothelium monolayer were compared between each groups. Results: The endothelial ultrastructure was more severely damaged in 60min and 90min groups than that in 0min and 30min groups revealed by TEM and the concentration of ET-1 is much higher in 60min and 90min groups than that in 0min and 30min groups (P<0. 01), but covering percentage of endothelium monolayer was similar in each group(P>0.05). The covering percentage of endothelium monolayer was similar in each group(P>0.05) at lday after operation which was displayed by â…§ R: Ag staining and SEM. In 30min groups, regeneration of the endothelial cells were observed at 3 days after operation and were almost covered the entire endothelium at 7 days after operation. Whereas in 60min and 90min groups, the endothelium were covered by EC until 14 days after operation. There was a difference of the endothelial regeneration between 30min groups and 60min, 90min groups respectively at 7 days after operation (P<0. 01), but no significant difference(P >0.05) between each groups at 14 days after operation. The apoptosis ratio of EC in 60min and 90min groups is much higher than that in 30min groups(P<0. 01) at 3 days and 7days after operation. There is no significant difference between each groups at lday and 14 days after operation(P>0.05). Conclusions: The conclusion is that EC would be damaged irreversibly after the ischemic time reach to 60 minutes. The safe ischemic time of endothelial cells of autologous vein graft is 60 minutes.