Background: Incomplete understanding of peritonitis pathogenesis may be the cause of slow tendency to decrease in mortality in this pathology.Objective: To study the activity of «L-arginine-NO-system», severity of oxidative stress and state of endothelium and peritoneum in rodent peritonitis.
Material and Methods:The experiments were carried out on male rats (n=36), divided into 2 equal series, which were injected intraperitoneally with: 1st series (control) -0,9% sodium chloride, 2nd series (experimental peritonitis, EP) -15 % fecal suspension, 0,6 ml/100 g. Studies were made after half a day (n=6), one day (n=6) and three days (n=6) of EP while an assessment of structural changes in the peritoneum were carried out after half a day and 3 days of EP. The level of nitrates/nitrites (NO x ), the activity of oxidative stress by measurement of the lipid peroxidation product, malondialdehyde, and an indicator of antioxidant protection, reduced glutathione, in blood plasma (BP) and peritoneal fluid were determined, along with the estimation of damage to endothelium of blood vessels basing on number of circulating endothelial cells in BP, and alteration of the peritoneum in preparations of the anterior abdominal wall and ileum stained with hematoxylin and eosin.Results and Discussion: During all the studied periods of EP, an increase in content of malondialdehyde and decrease in concentration of reduced glutathione were observed in BP and peritoneal fluid of rats, indicating development of oxidative stress, and elevation of number of circulating endothelial cells in BP, which corresponded to an unidirectional change in the level of NO x and could indicate a relationship between activation of inducible NO-synthase isoform, changes in prooxidant-antioxidant state and damage to endothelium of blood vessels. Revealed inflammation of the visceral and parietal layers of the peritoneum served as morphological substrate of acute EP, which was manifested by disorder of its structure, leukocyte infiltration and changes in microcirculation.
Conclusion:The study of the fecal peritonitis course in rats revealed: an increase in the content of NO x indicating enhance in NO production, as well as an increase in concentration of the lipid peroxidation product and a decrease in the level of antioxidant protection in blood plasma and peritoneal fluid, characterizing the development of oxidative stress; pronounced desquamation of endotheliocytes from the blood vessels wall, indicating the endothelial dysfunction; significant disorder of the peritoneum structure; development of changes in the studied parameters in all periods of experimental peritonitis to a greater extent in the peritoneum and peritoneal fluid than in blood, reflecting development of inflammation at the local level.