Phenotypic polymorphism of normal rat liver Kupffer cells
The aim of study was to evaluate the immunophenotype of resident macrophages of the liver, Kupffer cells, in rats in the norm. Material and methods. The study included male Wistar rats’ samples (n=6) that presented fragments of the middle lobe of the liver taken under ether anesthesia. The obtained samples were fixed in liquid nitrogen, after that cryosections 5-7 μm thick were prepared. Histological slides were used to detect the expression of a number of macrophage markers with an antibody kit: CD68, CD206, CD 163, CD86. After the first antibodies, sections were stained with antibodies conjugated to FITC, cell nuclei were detected using DAPI, the obtained preparations were studied using a fluorescence microscope. Results. When analyzing the expression of CD68 in the rat liver, it was found that normally about 20% of the cells in the field of vision appeared to be CD68<sup>+</sup> cells, which was consistent with the earlier study results of the authors. The number of CD163<sup>+</sup> and CD206<sup>+</sup> cells coincided with the number of CD68<sup>+ </sup>macrophages, while CD86<sup>+</sup> macrophages were significantly less. Conclusions. Under normal conditions, the population of resident macrophages of the rat liver is represented by cells with pronounced expression of CD68, CD163 and CD206. A large number of CD163<sup>+</sup> and CD206<sup>+</sup> macrophages allows concluding that Kupffer cells are close to the M2 pro-regenerative phenotype. However, the detection of CD86<sup>+</sup> resident macrophages indicates the presence of M1 macrophages, or the presence of normal macrophages with an intermediate M1 and M2 phenotype, in the rat liver. The revealed high content of macrophages expressing CD163 and CD206 in the liver evidences not only pro-regenerative properties of Kupffer cells, but also the close connection of macrophages with liver functions, since these receptors are involved in the utilization of hemoglobin and a number of hormones.