Abstract
It was shown the alterations in hydrogen sulfide (H(2)S) metabolism and the development of oxidative and nitrozative stress in cardiovascular system by aging. The administration of pyridoxal-5-phosphate as cofactor of H(2)S synthesizing enzymes restored endogenous H(2)S level and redox state in the heart and aorta tissues. Under these conditions, the following indicators of oxidative stress were significantly decreased in heart and aorta tissues: superoxide generation rate (·0(2)(-)) and hydroxyl (·OH) anion radicals, compared with significantly elevated levels of these parameters in old animals. We also found the reduction of non-enzymatic (diene conjugates and malonic dialdehyde) and enzymatic (uric acid, LTC(4) and TxB(2)) lipid oxidation products levels in old rats under H(2)S synthesis stimulation that confirms the restriction of oxidative stress. An important consequence of endogenous synthesis stimulation of hydrogen sulfide during aging is a decrease of nitrozative stress, such as iNOS activity and nitrate reductase, as well as recovery of constitutive NO synthase activity, indicating the importance of this gas transmitter in cardiovascular system. Thus, stimulation of hydrogen sulfide endogenous synthesis contributed to reduced production of reactive oxygen species (oxidative stress) and nitrogen (nitrozative stress) in heart and aorta tissues with aging. The presence of a pronounced antioxidant effect and modulating influence of pyridoxal-5- phosphate in the redox state of heart tissue and blood vessels during aging suggests cardioprotective properties of the substance and prospects for future research.
