Effects of zinc deficiency on impaired spermatogenesis and male infertility: the role of oxidative stress, inflammation and apoptosis

Abstract

Zinc (Zn) is necessary for the normal function of the male reproductive system and spermatozoa. Although influences of zinc deficiency on impaired spermatogenesis and male infertility have been widely considered, the molecular and cellular mechanisms of these abnormalities are not well understood. General abnormalities, including hypogonadism, Leydig cells damage, deficiency of sex hormone production and impaired spermatogenesis, as well as inflammation, antioxidant depletion, sperm death and male infertility can be observed during zinc deficiency. However, it is not obvious which pathways are relevant to the pathogenesis of zinc deficiency. Oxidative stress (OS) induced by reactive oxygen species is likely as the main mechanism of zinc deficiency which is associated with sperm DNA fragmentation, decrease in sperm membrane integrity, apoptosis, depletion of antioxidants, and consequently poor sperm quality and male infertility. Therefore, identification of these pathways will give valuable information regarding the mechanisms of zinc deficiency on the male reproductive system and the potential way for developing a better clinical approach. In this review, we aim to discuss the proposed cellular and molecular mechanisms of zinc deficiency on the male reproductive system, the importance of OS and mechanisms by which zinc deficiency induces OS and depletion of other antioxidants.

Relationship between serum zinc concentration and semen quality in newly‐wed men

“…Indeed, seminal plasma zinc concentration is related to semen quality and male infertility 6,9,21 . Zinc has been speculated to have several functions with regard to sperm 22 . The cell biologic functions of zinc, such as DNA replication and transcription, protein synthesis, cell proliferation, differentiation and apoptosis, are associated with major stages in sperm development.…”

“…6,9,21 Zinc has been speculated to have several functions with regard to sperm. 22 The cell biologic functions of zinc, such as DNA replication and transcription, protein synthesis, cell proliferation, differentiation and apoptosis, are associated with major stages in sperm development. Zinc regulates steroid hormone and testosterone synthesis and especially protects Leydig cells from damage due to its antioxidative properties.…”

“…Zinc also plays important roles in sperm capacitation and in the acrosome reaction. 22 However, the relationship between serum zinc concentration and the male reproductive system has not been fully investigated. It was first reported in 1977 that zinc administration raises sperm density.…”

Effects of Oxidative Stress on Spermatozoa and Male Infertility

“…Zinc concentrations of seminal plasma were found to be significantly lower in subfertile men [152]. Spermatozoa flagellar abnormalities, such as hypertrophy and hyperplasia of the fibrous sheath, axonemal disruption, defects of the inner microtubular dynein arms and abnormal or absent midpiece, are all associated with zinc deficiency [153]. Zinc given for 3 months in men with asthenozoospermia obtained a significant improvement in spermatozoa concentration, progressive motility and fertilizing capacity and a reduction in the incidence of anti-spermatozoa antibodies [153].…”

“…Spermatozoa flagellar abnormalities, such as hypertrophy and hyperplasia of the fibrous sheath, axonemal disruption, defects of the inner microtubular dynein arms and abnormal or absent midpiece, are all associated with zinc deficiency [153]. Zinc given for 3 months in men with asthenozoospermia obtained a significant improvement in spermatozoa concentration, progressive motility and fertilizing capacity and a reduction in the incidence of anti-spermatozoa antibodies [153]. Oral zinc supplementation successfully restored seminal catalase-like activity and improved spermatozoa concentration and progressive motility in a group of asthenozoospermic men [154].…”