Dynamics of Changes in the Secondary Structure of Fibrin under the Adrenaline Influence

It is known that intermolecular interactions, spatial orientation of molecules, changes in protein structure, and hydrophilicity largely determine enzymatic activity. This is particularly crucial during blood coagulation when fibrin is formed. Biologically active substances present in the blood can alter the coagulation process through intermolecular contacts, which may be due to a change in the secondary structure and spatial orientation of fibrin fibers. Adrenaline, a well-known stress hormone, may play a significant role in this process. A detailed analysis of the fibrin clot's secondary structure can be performed using infrared Fourier spectroscopy. This method makes it possible to study intermolecular interactions in proteins by assessing qualitative and quantitative changes in their structure and spatial orientation. To conduct the study, rats were subcutaneously injected with a solution of epinephrine hydrochloride at a dose of 2 mg/kg. Blood samples were taken from the animals’ left ventricle 30 min, 1 h, 24 h, 72 h after the administration of epinephrine Notable changes in the secondary structure of fibrin were observed upon adrenaline administration. After 30 min of exposure, α-spirals appear with a simultaneous decrease in β–structures, which indicates a greater looseness of the fibrin clot. These changes are amplified at the 1st h of exposure. By the end of the first day of observation, the α-spirals are unwound and the content of β-structures increases, but they do not reach the initial level. Such a change in the secondary structure contributes to the displacement of the liquid part of the plasma from the fibrin clot, leading to a decrease in its volume and an increase in density. On the 3rd day, the content of β–structures becomes less than the initial indicator, respectively, the density of the clot decreases, which may be a protective factor against thrombosis.