365 www.bsmiab.org/jabet Frolov et al., J Adv Biotechnol Exp Ther. 2021 Sep; 4(3): 365-375 Functional informativeness of lymphocytes’ cytomorphometric analysis of laboratory rats’ blood Oleksandr Kyrylovych Frolov 1 , Raisa Oleksandrivna Lytvynenko 1 , Lyudmyla Valeriyivna Makyeyeva 2 1 Department of Physiology, Immunology and Biochemistry with the Course of Civil Defense and Medicine, Faculty of Biology, Zaporizhzhia National University, Zaporizhzhia, 69600, Ukraine. 2 Department of Histology, Cytology and Embryology, Medical Faculty No. 2, Zaporizhzhia State Medical University, Zaporizhzhia, 69035, Ukraine * Corresponding author Raisa Oleksandrivna Lytvynenko Department of Physiology, Immunology and Biochemistry with the Course of Civil Defense and Medicine, Faculty of Biology, Zaporizhzhia National University, Zaporizhzhia, 69600, Ukraine. e-mail: r_litvinenko@ukr.net Academic editor Md Jamal Uddin, PhD Ewha Womans University, Seoul, South Korea Article info Received: 17 June 2021 Accepted: 03 August 2021 Published: 09 August 2021 Keywords Cytomorphometric classes of lymphocytes, experimental peritonitis, state of immunity ABSTRACT Immunological methods that objectively reflect the lymphogenetic processes in the examined organism are needed to assess the effectiveness of prophylactic or therapeutic agents that modulate regenerative processes in the immune system. Such requirements are met by the cytomorphometric method of analysis of circulating blood lymphocytes, the size (small, medium and large) populations of which reflect their proliferative processes in the lymphoid organs. However, the cytomorphometric characteristics of lymphocytes have species features that have to be determined experimentally. In the model of fecal peritonitis in white non-linear sexually mature male laboratory rats, the limits of statistical size classes of lymphocytes were determined, which were the same in control and experimental animals, namely: small – with a diameter of 8.5 μm and less, medium – with a diameter of more than 8.5 μm and less 11.0 μm, large – with a diameter of 11.0 μm and more. Acute infectious process significantly changed the levels of cytomorphometric classes of lymphocytes according to their functional activity in immunogenesis: small, medium and large size of lymphocytes as 42.5 to 7.0%, 45.0 to 54.0%, 10.5 to 39.0%, respectively, in the control and experimental groups of animals, which demonstrates the informativeness of the method. In this case, small and large lymphocytes belong to the activated lymphocytes, which determine the state of the immune system, while medium lymphocytes mainly make up the pool of memory cells. Based on the ratio of these size classes in the peripheral blood, a conclusion about the proliferative reaction of lymphocytes in the experiment is made, followed by the extrapolation of the results and in clinical practice. INTRODUCTION Objectification and personalization of the assessment of the state of immunity is a priority paradigm of modern laboratory diagnostics, and the development of computer technology will help automate and accelerate the results of the analysis. In this regard, modern advances in molecular cell biology have contributed to the progress of fundamental developments in the direction of modulation of regenerative processes in the immune system by natural and synthetic compounds. However, immunological methods that objectively reflect the lymphogenesis in the examined organism are needed to assess the effectiveness of the prophylactic or therapeutic agents application. The cytomorphometric method of the analysis of circulating blood lymphocytes meets such requirements. Cytomorphometry, as a method of computer image analysis includes analysis of nuclear and cellular morphometric parameters (radius, diameter, perimeter, area, volume, etc.), is widely used in laboratory diagnostics, medicine and veterinary medicine [1, 2]. Blood, as a part of the internal environment, reflects functional state of the organism and morphogenetic function of the immune system to ORIGINAL ARTICLE J Adv Biotechnol Exp Ther. 2021 Sep; 4(3): 365-375 eISSN: 2616-4760, https://doi.org/10.5455/jabet.2021.d136 Published by www.bsmiab.org