The aim of the study was an evaluation of viability and damage of biological cells sterilized with antibiotics and cryopreserved a year after the implantation. Sheep antibiotic sterilised and cryopreserved biological valves were implanted in tricuspid position in young sheeps for one-year period. After this time the valves removed and studied morphologically. The control group consisted of 7 intact valves, the comparative group, so called group of valves after the processing antibiotic sterilization and cryopreservation consisted of 7 valves after mentioned procedures. Histologic investigations were based on paraffin sections of formalin-fixed valve cusps, stained with H&E and Masson trichrome. Valve viability was assessed using intravital staining with fluoresceine diacetate, whereas damaged cells were visualized by intravital staining with neutral red. Additionally, the ultrastructural studies were performed. The viability and ultrastructural results were compared woth the pathologic process in the valve. Conclusions: 1. preliminary preparation with antibiotic sterilisation and cryopresrevation induces valve leaflet oedema and degenerative ultrastructural processes, colliquative cell necrosis and apoptotic morphology of a part of valve cells; 2. cryopreserved and antibiotic sterilised pulmonary valve after one-year implantation behaves living cells, but ultrastructural changes indicates many degenerative phenomena in smaller degree than after preparation, sterilization and cryopreservation. Histopathologically the degenerative changes were prevalent.

Keywords: Heart, Cell Viability, ultrastructure, Pathology, Biological Valve