Indices of peroxidation of proteins, lipids and antioxidant system as the markers of endogenous intoxication in patients with syndrome of obstructive sleep apnea

Abstract

The syndrome of obstructive sleep apnea (OSAS) is accompanied by episodes of hypoxia and reoxygenation, which causes an increase in the level of active forms of free radicals that lead to the development of the oxidative stress. The aim of this work was to investigate the intensity of peroxidation of proteins and lipids, the components of the antioxidant system and the biochemical parameters endogenous intoxication in patients with OSAS. Materials and methods: Twenty patients with OSAS were examined at the SI "Prof. O.S. Kolomyychenko Institute of Otolaryngology NAMS of Ukraine" (Kiev). They were divided into two groups: 10 of them were with apnea sleep index less than 30 episodes of respiratory arrest per hour (IA<30), another 10 ones – with more than 30 episodes (IA>30). The control group was consisted of 10 healthy persons. The object of biochemical studies was blood serum. The intensity of the oxidative modification of blood serum proteins was estimated by 2,4-dinitrophenyl hydrazine reaction by Levin in modification of Reznick. The evaluation of the intensity of peroxide processes was determined by interaction with 2-thiobarbiturac acid (TBA) by the method of Goncharenko. The activity of catalase was determined by the method of Korolyuk et al. The content of free thiol groups (SH-) was determined by interaction with 5,5'-dithio-bis-(2-nitrobenzoic acid) by the method of Sokolovsky et al. The contents of medium weight molecules and tyrosine-containing peptides (TCP) were determined spectrophotometrically at 254 and 280 nm, respectively. Statistical processing of results was carried out using a program package of biometric data WinPEPI. Results: In patients with OSAS whose IA<30, an increase of the level of TCP, oxidative modification of proteins, the content of TBA-positive products and a decrease in the level of SH-groups. In patients with IA>30, increased levels of medium weight molecules, TСP, oxidative modification of proteins, the content of TBA-positive products and the activity of catalase. A significant difference was observed in patients with syndrome of obstructive sleep apnea of varying degrees of severity of the content of aldehyde and ketone derivatives of neutral proteins; aldehyde derivatives of the main nature, the content of TBA-positive products and the activity of catalase. Conclusions: The results of the conducted studies indicate an increase in the intensity of the processes of peroxidation of proteins and lipids, the change in the components of the antioxidant system and the development of endogenous intoxication in patients with OSAS.