Levels of CD45+ and CD3+ cells in the liver during physical exertion of varying intensity and after administration of meldonium

Objective: to assess the proportion of leukocytes (CD45+ cells) and T-lymphocytes (CD3+ cells) in the liver during physical exertion of varying intensity with and without the use of meldonium. Materials and Methods. The experiments were conducted on male Wistar rats performing physical exercise of varying intensity. Meldonium was added to the feed of the experimental animals at a rate of 100–120 mg/kg of body weight during water-based exercise. After the experiment, liver samples were taken, sections were prepared and stained with hematoxylin and eosin, and immunohistochemical reactions were performed for CD45+ and CD3+ cell markers. Results. Under heavy physical exertion, the proportions of CD45+ and CD3+ cells in the liver parenchyma increased 3.2- and 2.9-fold, while perivascularly they increased threefold and 6.3-fold (p=0.001), respectively, vs. the intact group. After the administration of meldonium during heavy physical exertion, the percentage of CD45+ cells decreased in the liver parenchyma and perivascularly by 1.8 times (p=0.008), the proportion of CD3+ cells declined by 1.7 times in the liver parenchyma (p=0.001) and by 2.3 times around the blood vessels (p=0.004) vs. intact animals. Histologically, inflammation and degenerative changes in the liver tissue decreased. Conclusion. The use of meldonium during heavy physical exertion led to a decrease in the percentage of CD45+ and CD3+ cells due to a reduction in the degree of inflammatory infiltration of the liver tissue and the severity of the destructive process.