Role of Zinc (Zn) in Human Reproduction: A Journey from Initial Spermatogenesis to Childbirth

Abstract

Zinc (Zn), the second-most necessary trace element, is abundant in the human body. The human body lacks the capacity to store Zn; hence, the dietary intake of Zn is essential for various functions and metabolism. The uptake of Zn during its transport through the body is important for proper development of the three major accessory sex glands: the testis, epididymis, and prostate. It plays key roles in the initial stages of germ cell development and spermatogenesis, sperm cell development and maturation, ejaculation, liquefaction, the binding of spermatozoa and prostasomes, capacitation, and fertilization. The prostate releases more Zn into the seminal plasma during ejaculation, and it plays a significant role in sperm release and motility. During the maternal, labor, perinatal, and neonatal periods, the part of Zn is vital. The average dietary intake of Zn is in the range of 8–12 mg/day in developing countries during the maternal period. Globally, the dietary intake of Zn varies for pregnant and lactating mothers, but the average Zn intake is in the range of 9.6–11.2 mg/day. The absence of Zn and the consequences of this have been discussed using critical evidence. The events and functions of Zn related to successful fertilization have been summarized in detail. Briefly, our current review emphasizes the role of Zn at each stage of human reproduction, from the spermatogenesis process to childbirth. The role of Zn and its supplementation in in vitro fertilization (IVF) opens opportunities for future studies on reproductive biology.

Spermatozoan Metabolism as a Non-Traditional Model for the Study of Huntington’s Disease

“…Further, Zn 2+ is vital for the maintenance of normal spermatogenesis in rats [100][101][102], mice [103], and rams [104]; by maintaining male germ cell proliferation [100][101][102], by expression of testis germ cell-specific genes during the cell differentiation and spermatogenesis [104], and by regulating Leydig cell generation [100]. Zn 2+ accumulates in spermatocytes with its presence in the nucleus and chromatin [105], where it participates in the histone for protamine substitution event [98]; is required for the proper functioning of zinc finger protein (ZFP) transcription factors, such as ZFP185 or ZFP318 [106,107]; and stabilization of sperm chromatin with zinc bridges [108]. Furthermore, Zn 2+ stabilizes nascent outer dense fibers (ODF) of the sperm flagellum and protects them from premature oxidation [109,110].…”

Pronounced Trace Element Variation in Follicular Fluids of Subfertile Women Undergoing Assisted Reproduction

“…Experimental and clinical studies indicate that growth and fertility are strongly affected by trace element (TE) supply, and deficiencies are known to impair both male and female gametogenesis as well as embryonic development [14][15][16][17][18]. In particular, the trace elements copper (Cu), selenium (Se), and zinc (Zn) have emerged as the most essential micronutrients for both female and male fertility [19][20][21][22][23].…”

Heavy metal ion concentration in the amniotic fluid of preterm and term pregnancies from two cities with different industrial output

“…Due to these concerns, similarly to magnesium and iron, supplementation for both pregnant and lactating mothers is recommended. The average intake is in the range of 9.6-11.2 mg/day ( 51 , 52 ). Another reason to determine the amniotic fluid levels is that oxidative stress, induced by menadione, is further exacerbated by high concentrations (80 µM) of Zn ( 53 ).…”