The Relationship between p53-Positive Neurons and Dark Neurons in the Hippocampus of Rats after Surgical Interventions on the Nasal Septum.

The study evaluates the dependence of p53 protein expression on the appearance of dark neurons (DNs) in the hippocampus in rats during experimental modeling of septoplasty. Septoplasty simulation was carried out on 15 sexually mature male Wistar rats. We studied histological sections of the hippocampus stained with Nissl toluidine blue and antibodies to the p53 protein. In the CA1 subfield, the number of p53-positive neurons significantly increased on the 2nd, 4th (p < 0.001) and 6th days (p < 0.05). In the dynamics, the peak of the growth of p53 protein expression in the cytoplasm of CA1 and CA2 neurons fell on the 2-4th day after the operation, and on the 6th day the number of these neurons decreased (p < 0.001). In the cytoplasm of CA3 neurons in all periods after surgery, an increase in the expression of the p53 protein as compared to the control group was noted. In the CA1 pyramidal layer, the number of DNs decreased on the 6th day (p < 0.001). In CA2, after 2 days, a minimum of DNs as compared with the 4th day (p < 0.001) was noted. In CA3, on the 4th day, there was a peak in DNs as compared with the rest of the days (p < 0.001). A positive strong association was found in all periods of assessment and in all subfields of the hippocampus between an increase in the number of dark and p53-positive neurons. The appearance of dark and p53-positive neurons in the hippocampal formation in rats after simulating septoplasty are typical responses of nervous tissue to stress. It is obvious that the expression of the p53 protein is associated with the basophilia of the cytoplasm of neurons, their morpho-functional state. Presumably, the p53 protein can trigger not only the activation of damaged neurons in the hippocampus but also play a neuroprotective role. Upcoming studies should determine the role of the p53 protein in the further fate of damaged neurons in the pyramidal layer and differentiate the mechanisms of its expression.

Changes in the Time-Domain of Heart Rate Variability and Corticosterone after Surgical Trauma to the Nasal Septum in Rats.

The aim of the work was to study changes in the time range of heart rate variability (HRV) against the background of changes in the concentration of corticosterone in blood plasma in rats after surgical trauma to the nasal septum. Septoplasty was simulated in 30 mature male Wistar rats weighing 210-290 g. ECG was recorded with subsequent analysis of the time domain of HRV, as well as blood sampling to estimate changes in the concentration of corticosterone in the blood plasma was performed. As a result, SDNN significantly increased in comparison with the control on days 2 and 3 (p < 0.001) but decreased on days 4-5 (p < 0.001) and 6 (p < 0.01). rMSSD changed in waves with two irregular peaks on days 1 and 6. SDNN/rMSSD, in comparison with the 1st day of the postoperative period, increased on the 2nd day, continued to increase (p < 0.05), and then began to decrease on day 4 (p < 0.01). The total HRV power of was low throughout the postoperative period (p < 0.001), except for day 3, when it was equal to the control data. The increase in the total power index fell on day 3 after the operation (p <0.01), after which its decline was observed again. The concentration of corticosterone in the blood plasma in rats was significantly higher than before (p < 0.001). On postoperative day 2 to 4, its plateau was determined. Simulation of septoplasty leads to changes in the time range of HRV, an increase in the concentration of corticosterone in the blood plasma in rats with its maximum at the time of surgery and 24 h later, and the formation of a "plateau" on postoperative days 2 to 4, which coincides with the changes in HRV.

Comparison of the Effects of Septoplasty and Sinus Lifting Simulation in Rats on Changes in Heart Rate Variability.

The effects of septoplasty and sinus lifting simulation in rats on changes in the frequency domain of heart rate variability were compared. In the early postoperative period, the low-frequency component increases, and the high-frequency component decreases. The VLF range also increased. This indicates an increase in the activity of the sympathetic nervous system and a shift in metabolism under the influence of post-surgical inflammation.

Influence of Surgical Trauma in the Nasal Cavity on the Expression of p53 Protein in the Hippocampus of Rats.

The aim of the study was to determine the role of the stress effect of septoplasty modeling on p53 protein expression in the hippocampus of rats under conditions of sensory olfactory deprivation. Simulation of septoplasty was carried out on 30 sexually mature male rats. A quantitative assessment of the apoptosis of neurons in the pyramidal layer of the hippocampus in the subfields CA1, CA2, CA3, and dentate gyrus (DG) on days 2, 4, and 6 after surgery was carried out. Histological sections were stained by the immunohistochemical method with antibodies to the p53 protein. An increase in the number of p53-positive neurons was noted in all subfields; the maximum increase in the number of apoptotic neurons was noted on day 4 after surgery. The stress effect of modeling septoplasty in rats, accompanied by sensory deprivation of the peripheral part of the olfactory analyzer, provoked the expression of p53 and the initiation of apoptosis mechanisms in various subfields of the hippocampus.

Comparative ultrastructural study of the effect of imidazo-benzimidazole derivatives RU-185 and RU-254 on the development of microcirculatory disturbances in the skin under conditions of reduced blood flow.

In rats with experimental partial ischemia of the skin fold the state of microvessels and surrounding skin was studied by electron microscopy under control conditions and after treatment with imidazo-benzimidazole derivatives RU-185 and RU-254. RU-185 was more potent than RU-254 in preventing the development of microcirculatory disturbances and altered permeability of capillary walls.