Experimental Study On Dynamic Expression Of T-PA And PAI-1during Early Venous Crisis After Free Perforator Flap Transplantation

Objective:To investigate the dynamic expression of t-PA and PAI-1during early venous crisis after free perforator flap transplantation.Methods:Thirty healthy New Zealand white rabbits weighed2.5～3.0kg were chosen and randomly divided into experimental group (n=15) and control group (n=15), Free transplantation of SEAPF was implemented in all rabbits firstly. Then the model of venous crisis was established by ligating the anastomosis vein in order to interrupt venous blood outflow in experimental group. The blood supply of all flaps was monitored by observing their color, swelling degree and the filling reaction of the capillaries after operation. Peripheral blood was drawn from femoral artery at different time point for measuring the concentration of t-PA and PAI-1by Elisa. Partial flap tissue was harvested for pathological examination at corresponding time point. Data analysis was performed by using SPSS17.0statistical software. A p value of<0.05was considered statistically significant.Results:One rabbit died of anesthesia, and the venous congestion was observed in one rabbit in control group. The models of free transplantation of SEAPF and venous crisis were established successfully in the remaining rabbits. No significant appearance change was observed within1h after the outflow vein being ligated, while typical appearance of venous crisis could be observed2hours after the outflow vein being ligated. Compared with the control group, the concentration of t-PA is lower, but the concentration of PAI-1is higher in experimental group at2 hours,4hours,6hours,8hours after the outflow vein being ligated (P<0.05). However, there is no obvious differences between two groups at other time points (P>0.05). The pathological examination showed the red cells gradually got together and adhered to the venous wall, eventually the microcirculation had been blocked completely and the flap became necrosis after venous crisis being occurred.Conclusion:There is not enough evidence show that t-PA and PAI-1are valuable for diagnosing venous crisis early when a free perforator flap is transplanted.