NO-Synthase Pathway of L-Arginine Transformation in Spermatozoa of Infertile Men with Different Forms of Pathospermia

Abstract

Elucidation patterns of male germ cells functioning is of particular relevance in the present conditions due to increasing trends in male reproductive disorders [1]. Men infertility is caused by the effect of different pathological processes in genital organs and glands, resulting in pathospermia, which reduces fertilizing ability of sperm cells. Common methods for diagnosis of infertility including clinical and morphological, cytological, bacteriological methods do not always indicate the cause of the decrease in viability of spermatozoa and do not reveal mechanisms of the changes [13]. Over the past two decades a large amount of researches devoted to studying the role of nitric oxide and NO-synthase in the regu lation of physiological functions and pathological processes appeared. However, the role of NO-synthase in sperm cells in different forms of male infertility remains poorly understood [9, 11]. The NO formation in the human body is carried out as a result of oxidation of nitrogen atom that is part of the amino acid L-arginine by enzyme – Nitric Oxide Synthase (NOS) [4, 10, 11, 20]. There are three of its isoforms: neuronal – NOS (nNOS), inducible (macrophage) – NOS II (iNOS) and endothelial – NOS III (eNOS). Constitutive isoforms of NO-synthase (nNOS, eNOS) provide a synthesis of NO in physiological conditions. iNOS is inactive in physiological conditions and is activated in response to pathogenic stimuli [3–6, 12, 20, 26]. Therefore, the functional and regulatory features of inducible isoform of NOS depend on the nature of pathological process and the affected organ [12]. Both constitutive and inducible isoforms of NOS are related to NO production in the early phase of inflammation and their pro-inflammatory effect is manifested. Late phase of inflammation is associated with local leukocyte activity and infiltration. Its development is contributed only by NO, produced by iNOS, localized in leukocytes [12]. The elucidation of changes in NOS isoforms activity in men with impaired fertility determines actuality of present work. The aim of the research is to detect changes in the activity of NOS isoforms of sperm cells in patients with different forms of infertility. Materials and methods. Spermatozoa preparation. Semen samples of men aged 21–44 years were used in the research. Relatively healthy donors with no reproductive disorders and infertile men were among the men under study. The control group consisted of 20 healthy men with somatic fertility, normozoospermia and confirmed parenthood (married for 3–10 years and have 1–3 healthy children). Before turning to the study, all men had familiarized themselves with patient information leaflets and gave informed consent to participate in the research.