THE EFFECT OF ESTRADIOL ON THE TEMPORARY ORGANIZATION OF THE RAT OVARIAN MICROVASCULATURE
Objective: The dynamics of the structural organization of the rat ovarian microvasculature was studied at different times of a day with estradiol impact. Methods: The work was performed on the ovaries of two groups of mature Wistar female rats: control (n=24), whose animals were examined at 2, 6, 10, 14, 18, 22 hours, and experimental (n=20) -after administration of an oily estradiol solution dipropionate at night (2 and 6 hours) and day (14 and 18 hours) time. The alkaline phosphatase and NADPH-diaphorase activity in the vessel wall, the total length of enzyme-positive vessels in the ovarian cortex, and the relative density of mast cells were calculated. Results: In the night and morning hours, the capillaries in the cortical substance of the ovaries were characterized by an intense reaction to alkaline phosphatase and NADPH-diaphorase, and the density of such vessels was relatively high. In the daytime and evening hours, enzyme-positive vessels were less common, and capillaries with low or moderate enzyme activity prevailed among them. In addition to capillaries, on sections stained for NADPH-diaphorase, mast cells were detected in the interfollicular zones and stroma of the ovaries. The administration of estradiol caused an increase in the activity of alkaline phosphatase and NADPH-diaphorase in the capillary wall, an increase in the density of the perifollycular vascular network and mast cells. The values of enzyme activity and the number of mast cells increased by 8-12 %, more than the total length of the microvasculature. Conclusions: The administration of estradiol is accompanied by a restructuring of the vascular plexus of the ovarian cortex with an increase in the activity of alkaline phosphatase and NADPH-diaphorase in the wall of microvessels, an increase in the density of the enzyme-positive capillary network and the number of mast cells, among which degranulated forms are often occur. Changes in the structural elements of the ovary are more pronounced with the administration of estradiol in the daytime.