Hyaluronic Acid as a LYVE-1 Receptor Ligand in the Lymphatic System of Healthy Human Skin.

Immunohistochemical detection of the LYVE-1 marker in healthy human full-thickness skin (the epidermis and the dermis) was carried out. LYVE-1 expression was found in the endothelium of lymphatic capillaries located in the papillary dermis, in the endothelium of larger lymphatic vessels of the reticular dermis, and in fibroblasts, which indicates their joint participation in hyaluronan metabolism. LYVE-1 staining detected for the first time in cells of the stratum basale, the stratum spinosum, and the stratum granulosum of healthy human epidermis indicates their participation in hyaluronan metabolism and allows us to consider the spaces between epidermis cells as prelimphatics.

Effect of Melatonin on the Content of CD3 and CD3 T Cells in the Thymus of Mice with Functional Pinealectomy.

Continuous lighting for 14 days (functional pinealectomy model) leads to a decrease in the relative number of CD3 and CD3 T lymphocytes and the CD3/CD3 ratio in the thymus of C57BL/6 mice. Intragastric administration of melatonin in physiological doses (1 mg/kg body weight, 14 days) against the background of functional pinealectomy restores the percentage of CD3 and CD3 thymocytes and CD3/CD3 ratio to the control values. Hence, prolonged continuous illumination inhibits the differentiation and maturation of young thymocytes into mature forms, while melatonin treatment helps to compensate the effects of functional pinealectomy triggering cell proliferation in the thymus from the earliest stages of proliferation and differentiation of T cells.

Light-Induced Functional Pinealectomy. Effect on the Thymus of C57BL/6 Mice.

Light-induced functional pinealectomy was simulated in C57BL/6 mice by 14-day exposure to constant lighting. Immunophenotyping of CD3 and CD3 thymocytes was performed by staining with CD3-APC antibodies followed by flow cytofluorometry. To study the cell cycle distribution of thymus cells, the content of intracellular DNA was measured by the level PI inclusion.

Light-Induced Functional Pinealectomy: Expression of MT Receptors in Liver Cells of C57BL/6 Mice after Melatonin Treatment.

We performed an immunohistochemical study of MT melatonin receptor expression in the liver of C57BL/6 mice with modeled light-induced functional pinealectomy and after melatonin administration by the indirect avidin-biotin peroxidase ABC method. The animals were kept for 14 days under constant lighting. Intragastric administration of melatonin in physiological doses (1 mg/kg body weight for 14 days) to mice with light-induced functional pinealectomy resulted in a 2-fold increase in the relative expression area of MT receptors in liver cells in comparison with that in animals kept under standard lighting conditions, 24-h lighting for 14 days, or 24-h lighting receiving placebo (intragastric administration of 200 ml distilled water).

Effect of Melatonin on the Expression of LYVE-1 Receptor in Liver Sinusoidal Endothelial Cells of Mice with the Light-Induced Functional Pinealectomy Model.

Intragastric administration of melatonin in physiological doses (1 mg/kg body weight) for 14 days to C57BL/6 mice with light-induced functional pinealectomy model (24-h lighting for 14 days) results in an increase in the LYVE-1 expression area by 2.4 times and a significant increase in receptor concentration (1.6% decrease in staining brightness) in liver sinusoidal endothelial cells in comparison with animals kept under continuous lighting and not treated with the hormone, which indicates the formation of stability of the endothelial barrier in the organ.