Koruma solüsyonunun ve zamanının karaciğerin mekanik ve histolojik özelliklerine etkisi

In liver transplantation, most of the time, the donor and recipient are in different locations and longer preservation periods are inevitable. Hence, the choice of the preservation solution and the duration of the safe preservation period are critical for the success of the transplant surgery. In this thesis, we examine the mechanical and histological properties of bovine liver stored in Lactated Ringer's, HTK and UW solutions as a function of preservation period to investigate the efficiencies and safe preservation periods of these solutions. The mechanical experiments are conducted with a shear rheometer on cylindrical tissue samples extracted from three bovine livers and the change in viscoelastic material properties of the bovine liver is characterized using the fractional derivative Kelvin–Voigt Model. Also, the histological examinations are performed on the same liver samples under a light microscope. The results show that the preservation solution and period have a significant effect on the mechanical and histological properties of the liver tissue. The storage and loss moduli, the number of the apoptotic cells, the collagen accumulation, and the sinusoidal dilatation increase, and the glycogen deposition decreases as the preservation period is increased. Based on the statistical analyses, we observe that the liver tissue is preserved well in all solutions for up to 11 h. After then, UW solution provides a better preservation up to 29 h. However, for preservation periods longer than 29 h, HTK is a more effective preservation solution if the least amount of change in mechanical properties is considered as the criteria. On the other hand, the highest correlation between the mechanical and histological properties is observed for the liver samples preserved in UW solution.