Bobrova E. Influence of cryoprotectants and low temperatures on thermodynamic parameters and structural state of cord blood component human placenta

The thesis is devoted to the investigation of the influence 1,2-propanediol (1,2-PD), glycerol (Gl) and dimethyl sulfoxide (Me2SO) on phase and glass transitions of fetoplacental complex components below 0°С, the dynamics of the placenta saturation by cryoprotectants, as well as the influence of equalibration conditions with cryoprotectants and freeze-thawing on structural states of cord blood erythrocytes. The results received by DSC method indicate that the different kinetic units vitrify in the presence of the equal concentrations 1,2-PD, Gl and Me2SO. At the same time stability of the amorphous state is the highest with 1,2-PD. A high cell density promotes the development of glass-like phases while cooling, results in crystallization from the amorphous phase while heating and prevents crystallization of eutiectic compositions. It has been discovered that a rise in Gl and 1,2-PD concentrations causes an erythrocyte swelling, but high concentrations of Me2SO causes crenation. Optimal temperatures forcord blood erythrocyte ecvilibration in cryoprotectant solutions have been determined: Gl - 20°С; 1,2-PD and Me2SO - 0 °С. EPR method showed a damage of barrier functions of cord blood erythrocyte membranes in the presence of 30% Me2SO, 40% Gl and 1,2-PD. The investigation of saturation dynamics of placenta by cryoprotectants demonstrated that the process of tissue saturation by cryoprotectants had a two-phase nature.