Influence of refrigerated storage on tensile mechanical properties of porcine liver and spleen

Preservation conditions may affect internal organs thus influencing the results of protracted biomechanical tests. The influence of the freeze-thaw cycle on the mechanical behaviour of porcine abdominal organs was reported in our previous work. Here we further investigate the effects of refrigerated storage on the mechanical properties of porcine spleen and liver. Twenty-seven swine were chosen for tensile testing. To simulate the conservation conditions before biomechanical experimentation, the total sample was divided into three groups of nine individuals each and tested in a fresh state, after a freeze-thaw cycle, and after refrigerated storage (+4 °C). Fitted stress-stretch curves for each tissue type were obtained by employing a modified Fung model for isotropic behaviour. The results suggest statistically significant effects of refrigerated storage on the spleen but negligible influence on the liver. Similarly to the impact of the freeze-thaw cycle, refrigerated storage caused a decrease in the mechanical properties of the spleen. This again supports the hypothesized cause of the altered behaviour of spleen due to the autolysis of elastin by elastolytic enzymes during and after the cooling period. Spleen and liver are good examples of tissue with and without elastin. These findings have wide biomechanical and decomposition implications for the study of soft tissues.