Diffuse Endocrine System (DES) Cells of the Uterus Endometrium of Intact Rats in Different Phases of the Estrous Cycle

One of the important directions of contemporary gynaecological oncology is the study of various aspects of precancerous lesions pathogenesis and uterine cancer. The cells of diffuse endocrine system participate in the physiological and cyclical processes that take place in the genital organs, such as, the menstrual cycle in women and the oestrus in animals. Among all biogenic amines the serotonin is the most common in the diffuse endocrine system, which acts as a tissue hormone. The purpose of the study is examination of topography, morphology, and histophysiology of the uterine endocrine diffuse system cells in different estral cycle phases (estrus and estral rest) of intact rats. Materials and methods. The experiments were performed on laboratory white female rats with a body weight of 160-180 g, maintained into the standard vivarium conditions. The experimental material was divided into 2 groups (estrus and rest). Monitoring of estral cycle in rats was performed by vaginal cytology studying. Results and discussion. Serotonin-secreting cells with specific fluorescence were detected throughout the endometrium. Their density was 1792,8±76,11 much lower than in the control group (2010,47±101,59). The cells were characterized by small sizes and mostly by irregular or triangle shapes. Their volume was 922,97±52,93, which is much lower than in the control group (2964,32±67,64). In addition, the serotonin-secreting cells were contained fewer and smaller granules. Comparative to control group (17,77±0,14) one cell from this region had 10,82±0,17 granules in average. The fluorescence intensity was 0,12±0,002 units, which was lower than that recorded in the rest period (0,18±0,002). In addition to serotonin cells in the endometrium, fluorescent extracellular granules were also detected. They were in close proximity to the serotonin-secreting cells. Their density was 30076,7±1189,01 granules/1mm², which is practically similar to that of the control group (29491,38±930,14). The fluorescence intensity of those granules was 0,04±0,002 units, which was only slightly lower than in the control group (0,05±0,002). In estrus was observed the most low serotonin index (especially the intracellular serotonin) and secretory index (extracellular serotonin) comparative with the estral rest phase. Serotonin involvement in the cell differentiation and proliferation processes, both in physiological and embryonic cleavage conditions, opens the possibility of using this amine in medical practice. Thus, serotonin can be used in onco-gynecology to increase the resistance of the female body to cytostatic agents and to potentiate their therapeutic effect. However, until now, many important aspects of the histopathology and biochemistry of uterine DES cells remain unclarified, such as: changes in the synthesis and secretion of biologically active substances in physiological (estrus, ovarian-menstrual cycle, gestation, labour, post-partum involution) and pathological conditions (inflammation, tumour growth); the possibility of controlled change of these functions in order to correct deviations from the norm and for therapeutic purposes. Conclusion. Oestrus is characterized by quantitative diminution of DES cells in the endometrium, numeric reduction of serotoninic granules in the cells, decreased fluorescence, but with constant extracellular granules number maintaining. These data shows that the uterine decreasing of serotonin in oestrus is produced predominantly by slowed down synthesis and accumulation processes, but not by cell secretion increasing.