Role of surgical trauma in the hippocampal dopaminergic system response in simulated surgical interventions on the nasal cavity, paranasal sinuses, and alveolar process of the maxilla in rats

Aim of the study: to evaluate the impact of surgical trauma on the hippocampal dopaminergic system response in simulated surgical interventions on the nasal cavity, paranasal sinuses, and alveolar process of the maxilla in rats. Material and methods. Surgery simulation was performed on male Wistar rats under general anesthesia with Zoletil 100 solution. Septoplasty was simulated in group 1 (n=10). Dental implantation was performed in group 2 (n=10). In group 3 (n=10), a cavity was created in the alveolar process of the maxilla. In group 4, 10 rats underwent sinus lift surgery with dental implantation. In group 5 (n=10), maxillary sinusotomy was performed with injury to the mucosa of the ipsilateral maxillary sinus. Liquid chromatography with electrochemical detection was used to determine the concentration of dopamine (DA), homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine (3-MT) in the hippocampal formation. The DOPAC/DA, HVA/DA, 3-MT/DA ratios were also determined. The control group included 10 intact rats of the same lineage. Results. The DA concentration in the hippocampus was significantly higher in group 5 and lower in group 4 compared with the control. HVA concentration was significantly higher in group 2, in group 5 (p<0.01) and in group 1 (p<0.05). Inter-group comparison revealed that HVA concentration was significantly higher in group 2 compared with the rest of the experimental groups (p<0.001). This parameter was significantly lower in groups 1, 3, and 4 compared with group 5 (p<0.01). DOPAC level was significantly higher in group 5 (p<0.01) compared with the control data. 3-MT concentration was significantly higher in groups 4 and 5 (p<0.001), as well as in groups 1 (p<0.05) and 3 (p<0.01). DOPAC/DA was significantly lower in groups 2 and 4 compared with controls (p<0.001), which was also observed in group 5 (p<0.01). HVA/DA ratio was significantly lower in groups 4 and 5 compared with the control animals (p<0.001). The 3-MT/DA ratio was significantly lower in groups 2 and 5 (p<0.01) as well as in group 4 (p<0.001) compared with the control group. Conclusion. The concentration of dopamine metabolites 3-MT, HVA, and DOPAC increases, while the dopaminergic activity of the hippocampal formation decreases in simulated sinus lift surgery with simultaneous implantation and dental implantation complicated by maxillary sinusotomy compared with the parameters in simulated septoplasty and simple maxillary alveolar process injury. Surgical trauma during the simulated operations on the nasal cavity, paranasal sinuses, and alveolar process of the maxilla in rats provokes a pronounced stress response of the hippocampal dopaminergic system, which can be interpreted as disruption of adaptive mechanisms and the development of maladaptation in the early postoperative period. Key words: dental implantation, sinus lift surgery, septoplasty, hippocampus, dentate gyrus, dopamine, homovanillic acid, DOPAC, 3-MT, DOPAC/DA, HVA/DA, 3-MT/DA Conflicts of interest. The authors have no conflicts of interest to declare. Funding. There was no funding for this study