Assessment of the degree of mitochondrial protein carbonylation in rats at modulation of NO synthesis, hypoxia and its correction by succinat

Introduction. Carbonylation, as a variant of oxidative modification of proteins, serves as an indicator of tissue damage during oxidative stress, including that caused by hypoxia. Some regulators of the metabolic response to oxygen deficiency, such as the NO donor arginine and the mitochondrial metabolite succinate, are also able to influence the modulation of cellular antioxidant defense and oxidative stress.

The aim of the study was to evaluate the effect of arginine and succinate in combination on the degree of protein carbonylation and antioxidant status during hypoxia.

Material and methods. The study included 40 wistar rats divided into 5 groups (n=8): animals exposed to normobaric chronic hypoxia while being kept in a hermetic chamber until the oxygen level decreased to 10% once a day for 14 days (1); receiving arginine at a dose of 500 mg/kg b.w. per day for 10 days (2); succinate at a dose of 100 mg/kg b.w. per day for 14 days (3); receiving arginine and succinate (4); exposed to hypoxia and receiving arginine and succinate (5). In the mitochondria of the seminal vesicles and epididymis, the activity of superoxide dismutase was assessed by inhibition of the reaction with quercetin, the degree of protein carbonylation by the reaction with 2,4-dinitrophenolhydrazine, from which the reserve-adaptive oxidative modification potential of proteins was calculated. The Mann-Whitney criterion was used for statistical analysis.

Results. The combination of arginine and succinate resulted in an increase in the degree of protein carbonylation and a decrease in the reserve-adaptive oxidative modification of mitochondrial proteins of the seminal vesicles and epididymis, while the superoxide dismutase activity remained at the level of group 2, which is lower than in group 3. The complex effect of the studied metabolites under hypoxia had a protective effect on mitochondrial proteins, reducing the degree of their oxidative modification, which is especially true for mitochondrial proteins of the epididymis head.

Conclusions. Under conditions of physiological NO synthesis, succinate helps maintain superoxide dismutase activity, which does not occur under hypoxia-like conditions. Activation of NO synthesis by arginine in a complex with succinate is an effective way to correct the oxidative modification of mitochondrial proteins under hypoxia.