Expression of CD11a⁺ and CD309⁺ membrane lymphocyte clusters as biomarkers of the effect of combined exposure to benzo(a)pyrene and cold factor in experimental in vivo models

Introduction. It is relevant to investigate expression of CD11a+ and CD309+ markers under combined exposure to benzo(a)pyrene and cold factor in an in vivo experiment in terms of modelling likely effects and verifying mechanisms of the developing of disorders of endothelial immune regulation caused by biological exposure to benzo(a)pyrene in northern areas.Materials and methods. An in vivo subchronic experiment was performed using forty eight nonlinear laboratory mice divided into 4 groups according to the conditions of factor loading (oral biological exposure to benzo(a)pyrene at an average daily dose of 0.175 mcg/kg∙day; exposure to cold, average daily air temperature 9.9±2.6 °C). The content of CD11a+ and CD309+ lymphocytes was determined by flow cytofluorometry.Results. The results of oral subchronic biological exposure to benzo(a)pyrene at a dose of 0,175 µg/kg×day under cold stress in an in vivo experiment made it possible to establish CD309+ lymphocytes overexpression against the background of CD11a+ cells decrease (OR=5.00–22.50; RR=2.63–4.20; p=0.001–0.042). An increase in CD309+ lymphocytes content by 62% relative to the control is mainly associated with biological exposure to benzo(a)pyrene (OR=11.25 (1.65-76.85); RR=2.86 (1.20–6.86); p=0.026) while a decrease in CD11a+ lymphocyte content is associated with cold stress (OR=11.00 (1.77–68.35); RR=3.50 (1.22–10.05), p=0.001). Combined exposure to benzo(a)pyrene and cold forms synergistic, more than additive effects in the cellular immune profile (OR=14.67–22.50; RR=3.15–4.20; p=0.001–0.042).Limitations. The limitations are related to quantitative parameters of the sample, limited choice of exposure factors, and the need for subsequent confirmation of obtained results. Conclusion. Thus, the imbalance of adaptive cellular immune profile identified in in vivo models (CD309+ activation, CD11a+ deficiency) reflects the launch of negative inflammatory and proliferative scenarios associated with cardiovascular diseases. This makes it possible to verify mechanisms of cold and chemical (benzo(a)pyrene) stress formation and recommend CD11a+ and CD309+ lymphocyte clusters to be used as biomarkers of the effect for biological exposure to benzo(a)pyrene in northern areas.Compliance with ethical standards. The study was conducted in compliance with the requirements of the European Convention for the Protection of Vertebrate Animals used for Experimental and Other Scientific Purposes (ETS No. 123) and the Local Ethics Committee of the Federal Research Center for Medical and Preventive Health Risk Management Technologies (The meeting protocol No. 2 dated January 17, 2022).Contribution: Dolgikh O.V. — study concept and design, editing the text; Nikonoshina N.A. — data collection and analysis, writing the text. All authors are responsible for the integrity of all parts of the manuscript and for the approval of its final version.Conflict of interest. The authors declare no conflict of interest.Acknowledgement. The study had no sponsorship.Received: February 17, 2024 / Revised: March 6, 2024 / Accepted: March 26, 2025 / Published: April 30, 2025

benzo(a)pyrene, cold stress, lymphocytes, mice, immune profile, in vivo experiment