ENDOTHELIAL DYSFUNCTION UNDER EXPERIMENTAL SUBARACHNOID HEMORRHAGE. POSSIBLE WAYS OF PHARMACOCORRECTION

Abstract

Purpose of the article: to study the effect of acelysine and nimodipine on certain endothelial dysfunction indicators and to evaluate their therapeutic efficacy after subarachnoid hemorrhage in rats. Materials and Methods: an experimental study was carried out using 50 Wistar rats of both sexes. Spontaneous subarachnoid hemorrhage was modeled in animals. Three groups of animals were identified: a control group, a group of animals received a standard therapeutic dose of acelysine, and a group received a standard therapeutic dose of nimotop. Each group included 15 animals. There were also 5 intact animals. The animals were withdrawn from the experiment on days 4 and 7 after the motor and exploratory activity determination. Motor and exploratory activity determination was carried out following SAH with the “Open Field” technique. Determination of biochemical markers of endothelial dysfunction was performed in a rat brain homogenate. Results and discussion. It was found that modeling of subarachnoid hemorrhage (SAH) led to the oxidative stress development development and the product of oxidative modification of proteins (nitrotyrosine (Ntz) on the 4th and especially on the 7th day of the experiment) increase in the brain tissues. Starting from the 4th day, we registered a compensatory increase in the activity of NO-synthase (NOS) - by 56%, followed by a decrease in its activity on the 7th day, by more than 33% against the intact group of animals. It was registered a compensatory increase in VEGF-A in rats with SAH modeling on the 4th day of the experiment and its further decrease on the 7th day. The established pathobiochemical changes in the brain tissue were accompanied by the cognitive deficit development in experimental animals, especially on the 7th day of the SAH. SAH led to a significant decrease in the total activity of animals by 2.63 times, a decrease in the distance traveled by animals by 1.89 times, the number of freezes increased by 1.86 times and the immobility of animals increased when moving from the periphery to the center and immobility in the center of the arena (anxiety, fear, disorientation), as well as a decrease in the distance traveled and the speed of movement in illuminated center of the arena 2 and 2.6 times, respectively. Experimental therapy with acelysine 15 mg/kg led to the normalization of biochemical indicators of endothelial dysfunction: concentration of nitrotyrosine, starting from the 4th day of the experiment, increased eNOS activity and VEGF-A concentration (by 75% and 64% on 7th day). The administration of namidopine led to less pronounced effects, statistically significant changes occurred only in relation to the VEGF-A concentration. Administration of namidopine resulted in only a slight increase in VEGF-A concentration. Acelysine and nimotope significantly increased the total activity of rats on the 7th day after SAH by 76.3% and 48.8%, respectively. In animals treated with acelysine, anxiety and fear decreased. The animals were less aggressive and more empathic - long-term grooming increased 3 times. The administration of nimotop in rats survived SAH had a less pronounced positive effect on behavior. Nimotop did not effect on indicators of general activity and did not increase the total distance traveled. Animals received nimtop were inactive by the 7th day of treatment. Conclusions: Experimental therapy with acelysine led to the normalization of biochemical parameters of endothelial dysfunction, namely nitrotyrosine concentration, starting from the 4th day of the experiment and increased eNOS activity and VEGF-A concentration. It should be noted that, in contrast to the rats of the control group, under prescription of acelysine, there was an increase in the concentration of eNOS and VEGF-A both on the 4th and 7th days of the experiment. The administration of namidopine led to less pronounced effects, statistically significant changes occurred only in relation to the VEGF-A concentration. The administration of acelysin to animals after SAH had a beneficial effect on the emotional status and behavior of animals, and also led to the normalization of their general activity and orientation-exploratory activity. The mechanism of edotheliotropic effect of acelysine, in our opinion, is associated with its antioxidant effects, modulating impact on endothelial NOS, as well as its property, indirectly, to influence on increase VEGF content. Nimotope therapy had no effect on the emotional status and behavior of the animals. The use of calcium channel blockers revealed such side effects as depression, drowsiness, diplopia, and disorientation