ИСТИНА

Erythrocytes aggregation (EA) significantly affects the viscosity of blood which, in turn, influences the process of blood fluidity in the body. The mechanisms of EA phenomenon are not fully investigated so far. However, it is known that the parameters of EA depend on the constitution of the blood plasma and the concentration of the different proteins. At normal conditions, i.e., in healthy individuals, the concentrations of different proteins are different. As a continuation of our previous work [1], in which the effects of fibrinogen, gamma-globulin on aggregation parameters were measured separately. Earlier, the effects of fibrinogen and albumin on EA were considered in works [2, 3]. In this work, we consider the effects of fibrinogen and gamma-globulin on paired EA after in vitro incubating the erythrocytes suspension with these proteins separately or together. Laser tweezers is a device for manipulating and trapping a single particle into an optical trap, which is a focused laser beam. The principle of operation of the laser tweezers is based on the use of forces acting on the object from the side of the laser light beam. Laser tweezers (Nd:YAG laser, wavelength: 1065 nm, power: 100 mW) were used for measuring the aggregation time (AT), aggregation and disaggregation forces (AF, DF) in suspensions of highly diluted erythrocytes on cellular level: AT – time starting from the moment of contact of two erythrocytes and ending with the moment of formation of the aggregate; AF - the minimum value of the optical trapping force that can prevent the aggregation of erythrocytes; DF - the minimum force required to separate the pair aggregate of erythrocytes. The obtained results show that variation of the amount of gamma-globulin within the range of normal physiological concentrations (6 – 16 mg/ml) does not change the EA parameters. In contrast, the variation of the amount of fibrinogen within the range of normal physiological concentrations (2 – 4 mg/ml) gradually changes the EA parameters. However, with further increase of the concentration of these proteins both of them exhibit the proaggregant action. Comparing their influence on AE, we showed that the effect of fibrinogen up to tested concentration of 10 mg/ml is higher than that of gamma-globulin with corresponding maximum tested concentration 15 mg/ml. Detailed relationship of fibrinogen and gamma-globulin with AE parameters is discussed. This work was supported by the Russian Science Foundation (Grant No. 22-15- 00120) and performed according to the Development program of the Interdisciplinary Scientific and Educational School of Lomonosov Moscow State University «Photonic and Quantum technologies. Digital medicine». [1] K. Korneev et al., “Comparison of the effect of fibrinogen and gamma globulin on the aggregation of erythrocytes of a healthy donor in vitro by optical techniques”. Abstracts of the XXIX International Conference "Lomonosov-2022" (Moscow, Russia, 2022), p. 684. [2] K. Lee et al., “Optical tweezers study of red blood cell aggregation and disaggregation in plasma and protein solutions “. JBO 21(3), 035001 (2016), DOI: 10.1117/1.JBO.21.3.035001. [3] A. Semenov et al., “Optical trapping and diffuse light scattering techniques for in vitro assessing the effect of albumin and fibrinogen synergy on red cells aggregation in blood plasma”. Abstracts of the 25th International Conference on Advanced Laser Technologies “ALT-17” (Busan, Korea, 2017), p. 174