Indicators of the cell cycle in the thyroid gland in rats when applying infusion of 0.9% solution of NaCl, lactoprotein with sorbitol or HAES-LX 5%

Abstract

The thyroid gland is an important organ that is involved in the regulation of homeostasis and adaptation in various pathological conditions. However, the question of the study of the proliferative activity of thyroid cells by flow cytometry is still poorly understood. Purpose of study: to investigate the indices of the cell cycle and DNA fragmentation of thyroid cells in rats against the background of infusion of 0.9% NaCl solution, lactoprotein with sorbitol or HAES-LX 5%. Experimental studies were performed on 90 white male rats weighing 160-180 g. Infusion of 0.9% NaCl solution, lactoprotein with sorbitol or HAES-LX 5% was performed in the inferior vena cava after its catheterization in aseptic conditions through the femoral vein. The infusions were performed once a day for the first 7 days. Trunk catheterization and decapitation of animals (after 1, 3, 7, 14, 21, and 30 days) were performed under propofol anesthesia (60 mg/kg i/v). Within the framework of the agreement on scientific cooperation between the Research Center of National Pirogov Memorial Medical University, Vinnytsya and the Department of Histology, Cytology and Embryology of the Odessa National Medical University (from 01/01/2018), DNA content in the nuclei of thyroid cells of rats was determined by flow DNA cytometry. Cell cycle analysis was performed using the software FloMax (Partec, Germany) in full digital accordance with the mathematical model, which determined: G0G1 – the percentage of cells of the phase G0G1 to all cells of the cell cycle (DNA content = 2c); S – the percentage of the phase of DNA synthesis to all cells of the cell cycle (DNA content > 2c and < 4c); G2+M – the percentage ratio of the G2+M phase to all cells in the cell cycle (DNA = 4c). Determination of DNA fragmentation (SUB-G0G1, apoptosis) was performed by isolating the RN2 region on DNA histograms before the G0G1 peak, indicating nuclei of cells with a DNA content < 2c. The statistical processing of the obtained results was carried out in the license package “STATISTICA 6.1” using nonparametric estimation methods. The data obtained showed a virtually identical pattern of rat cell cycle and DNA fragmentation of the thyroid gland cells at all study times against the use of 0.9% NaCl solution, lactoprotein with sorbitol or HAES-LX 5%. Thyroid cells in rats are predominantly in the inactive phase of DNA synthesis (G0G1) (90.32% – 91.88%), significantly fewer cells are in the G2+M phase (7.56% – 9.17%), and there is a small percentage of cells in the S-phase (DNA synthesis) (0.52% – 0.67%) and the SUB-G0G1 interval (DNA fragmentation, apoptosis) (2.23% – 2.81%). We can state that the activity of the main part of the thyroid gland is rather low without pathological irritation.