Gender specificity of reactivity rat skins microvessels according to laser doppler flowmetry

   Introduction. In the development of systemic microcirculation disorders, gender is known to have a certain significance. However, the features of the microvessels reactivity and their functional reserve have not been sufficiently studied.   Purpose – to study the gender specificity of the microvessels reactivity of rat skin according to LDF data in the conditions of functional tests.   Materials and methods. The study was carried out on male and female Wistar rats. Females with a stable 4-day estrous cycle according to colpocytogram data were selected for the experiment. The LDF method was used to evaluate the initial skin perfusion and its dynamics under the conditions of a test with local contact hypothermia induced by a thermoelement. The distribution of temperature fields was evaluated using a FLIR ONE Pro thermal imaging camera.   Results. While contact cooling of the skin, microvessels developed a reaction having phase pattern. Immediately after exposure, local contact hypothermia was accompanied by a significant decrease in skin temperature and tissue perfusion (in the area of laser flowmetry). At the same time, males had higher percentage of reduction in skin blood flow (Q %) than females and amounted to 54 % of the initial values. The maximum perfusion after the restoration of blood flow was noted at the 5th minute in males, at the 3rd minute in females and amounted to 147 % and 149.9 %, respectively. The initial blood flow in the skin microvessels in different phases of the estrous cycle in females did not differ significantly. However, when conducting a functional test in the proestrus stage, characterized by the maximum secretion of estrogens by the ovaries, vasoconstriction was less pronounced than in other phases of the cycle.   Conclusion. The revealed features of blood flow reduction followed by «cold vasodilation» under conditions of local contact hypothermia tests indicate a greater functional reserve of microvessels and a more effective mechanism of autoregulation of the microcirculation system in female rats.