LAPAROTOMY ENHANCES THE PRODUCTION OF REACTIVE NITROGEN SPECIES IN THE HEARTS OF RATS EXPOSED TO A SINGLE PROLONGED STRESS

Abstract

The aim of this study was to assess the production of reactive nitrogen species in the hearts of rats subjected to surgical trauma simulated against the background of post-traumatic stress disorder (PTSD). Materials and methods.The study was conducted on 42 white Wistar rats weighing 210-230 g, then divided into 6 groups: Group 1 consisted of intact animals, Group 2 included animals exposed to the induction of the PTSD model through single-prolonged stress (SPS), Group 3 – rats subjected to a sham operation, Group 4 – animals undergoing laparotomy, Group 5 – rats undergoing a sham surgical operation following SPS, and Group 6 – animals undergoing laparotomy under modeled SPS. NO synthase activity in the heart homogenate was determined spectrophotometrically. Results. The formation of peroxynitrite was assessed by the content of peroxynitrite of alkaline and alkaline-earth metals. SPS exposure significantly increases the production of reactive nitrogen species in the hearts of rats, in particular, it enhances NO synthase activity by activating the inducible isoform and reduces the activity of constitutive NO synthases, which is accompanied by the growth in the concentration of peroxynitrites. On the 7th day after laparotomy against the background of the experimental PTSD model, the indicators of nitrosative stress in the hearts of rats (total and inducible NO synthase activity and peroxynitrite concentration) significantly exceeded their values in the groups subjected to a single laparotomy and to a sham operation against the background of simulated SPS.