The Mechanism of Zinc Sulfate in Improving Fertility in Obese Rats Analyzed by Sperm Proteomic Analysis

Progress on the roles of zinc in sperm cryopreservation

One of the effective methods for the long-term preservation of mammalian genetic resources is the cryopreservation of semen. However, a number of parameters, including diluents, the rate of freezing and thawing, cryoprotectants, etc., can easily alter the survival of frozen-thawed sperm. Numerous studies have documented the addition of a variety of zinc compounds, to the diluents used to cryopreserve sperm. The primary objective of this review is to briefly describe that adding zinc to diluents as an antioxidant significantly enhances frozen-thawed sperm quality. Second, a summary of the present understanding of zinc's molecular mechanism on semen cryopreservation is provided. Thirdly, this study addresses that nanoparticles of zinc can offer suggestions for raising cryopreservation effectiveness.

Zinc Improves Semen Parameters in High-Fat Diet-Induced Male Rats by Regulating the Expression of LncRNA in Testis Tissue

This study aimed to identify differentially expressed LncRNAs in testis tissue of male rats induced by high-fat diet and their changes after zinc supplementation, by constructing a high-fat feeding rat model, and then supplemented with zinc, and observed the expression of LncRNA in three groups of normal, high-fat fed, and zinc-intervened rats. Experimental studies show that the semen parameters of male rats with high-fat diet were decreased but recovered after zinc supplementation, and the related LncRNA also changed. Zinc may improve the high-fat diet-induced reduction of semen parameters by changing the expression of related LncRNA.

Implication of apoptosis and oxidative stress in mitigation of ivermectin long-term hazards by zinc nanoparticles in male rabbits

Ivermectin is the medication of choice for treating human onchocerciasis and is used in veterinary medicine to treat a variety of ectoparasites and endoparasites. This study was designed to investigate the effects of zinc nanoparticles (ZnNPs) on the fertility of male rabbits exposed to experimental ivermectin (IVM) intoxication. A total of 72 mature male rabbits were equally divided into 4 groups (n = 18). The first group (CTR) served as control; the second group (IVM) received subcutaneous injection of IVM (0.2 mg/kg body weight); the third group (ZnNPs) fed on zinc nanoparticles (60 mg/kg diet); and the fourth group (ZnNPs + IVM) were administered IVM and zinc nanoparticles at the same doses. The experiment lasted for 9 weeks. Results revealed that IVM-intoxicated rabbits showed impaired growth performance parameters, including body weight, total body weight gain (TBWG), total feed intake (TFI), and feed conversion ratio (FCR). Moreover, carcass characteristic and fertility parameters (including semen quality parameters and testosterone levels) were also impaired after IVM administration. Additionally, testicular malondialdehyde (MDA) and antioxidant (reduced glutathione, superoxide dismutase, catalase) levels as well as the histopathology and immunohistochemical expression of caspase 3 and PCNA in the testes and epididymis were detrimentally affected. On the contrary, ZnNP administration efficiently improved most of these parameters in IVM-intoxicated rabbits. In conclusion, ZnNPs exhibited promising ability for improving the growth and fertility status of rabbits and reducing the deleterious effects of IVM possibly through the suppression of apoptotic and oxidative pathways.

The combination of ginger and zinc supplement could improve lead-induced reproductive dysfunction by inhibiting apoptosis mediated by oxidative damage and inflammation

Due to the growing industry and industrialization of many urban communities, one of the dangers that threaten human life is long-term exposure to heavy metals such as lead. Lead contamination can have a detrimental effect on fertility. On the other hand, the combination of ginger and zinc supplements can be a powerful sexual enhancer. Despite extensive studies on the effect of ginger and zinc on reproduction, the effects of the combination of ginger and zinc supplement on lead-induced reproductive dysfunction are not fully understood. Sixty-four adult male rats were allocated into control, lead acetate (10 mg/kg), ginger (250 mg/kg), ginger-lead group, zinc (120 mg/kg) group, zinc-lead group, ginger-zinc group and ginger-zinc-lead group. The drugs were administrated by gavage for 4 weeks. The concentration of LH, FSH, testosterone, TNF-α, IL-1β, antioxidant enzyme activity, MDA, spermatogenesis, and sperm parameters were measured. The expression of NF-kB, Nrf2, Bcl2, BAX, and Cas-3 was evaluated. The histopathological assessment was also detected. Lead significantly could induce inflammation, apoptosis, and oxidative damage in testis tissue, and decrease hormonal levels, spermatogenesis, and sperm parameters compared to the control group (p < 0.05). While in reverse manner ginger, zinc, and their combination significantly improved all of them compared to the lead group (p < 0.05). These results were also supported by histological findings. It can be concluded that ginger, zinc, and their combination could prevent lead-induced reproductive dysfunction by inhibiting apoptosis mediated by oxidative damage and inflammation and improve reproductive performance.

Comparative Potential of Zinc Sulfate, L-Carnitine, Lycopene, and Coenzyme Q10 on Cadmium-Induced Male Infertility

The human exposure to toxic chemicals and heavy metals is one of the main predisposing factors contributing to male infertility. Acute exposure to cadmium chloride results in testicular damage and infertility. The purpose of the present study was to investigate and compare the curative effect of coenzyme Q10 (CoQ10), lycopene, L-carnitine (LC), and zinc sulfate against the cadmium-induced infertility in male Wistar rats. Cadmium chloride (0.4 mg/kg/day) was orally administered to rats for three consecutive days. Then, oral administration of different treatments (i.e., LC 100 mg/kg, CoQ10 20 mg/kg, lycopene 4 mg/kg, zinc sulfate 6 mg/kg, and a combination LC-CoQ10 at 500/50 mg/kg) was carried out for 30 days. The impact of different treatments on semen parameters, such as sperm count and motility, testicular antioxidants, and serum testosterone, was determined. Furthermore, the morphology of epididymis sperms and histopathology of rat testes were also assessed. Cadmium exposure decreased the sperm count, progressive sperm motility, testosterone, superoxide dismutase (SOD), and catalase and reduced glutathione (GSH). It also caused banana sperm tail, bent sperm head, vacuolization of seminiferous tubules, and oligospermia in rat testes. All treatments with nutraceuticals improved sperm count, sperm morphology, serum testosterone, vacuolization of seminiferous tubules, and oligospermia in diseased rats. Treatment with lycopene, LC, and LC-CoQ10 improved progressive sperm motility and other parameters and increased SOD, GSH, and CAT in the rat testes. CoQ10 also increased SOD activity in rat testes' tissue homogenates. It is concluded from the current study that all nutraceuticals partially improved reproductive toxicity of cadmium. The administration of lycopene and a high-dose combination of LC-CoQ10 were more efficacious in treating cadmium-induced infertility than other treatments. Treatment of cadmium-exposed rats with lycopene, LC, CoQ10, and LC-CoQ10 improved sperm count and motility through reduction of testicular oxidative stress and improving serum testosterone.

The Role of Zinc in Male Fertility

Several studies proposed the importance of zinc ion in male fertility. Here, we describe the properties, roles and cellular mechanisms of action of Zn²⁺ in spermatozoa, focusing on its involvement in sperm motility, capacitation and acrosomal exocytosis, three functions that are crucial for successful fertilization. The impact of zinc supplementation on assisted fertilization techniques is also described. The impact of zinc on sperm motility has been investigated in many vertebrate and invertebrate species. It has been reported that Zn²⁺ in human seminal plasma decreases sperm motility and that Zn²⁺ removal enhances motility. Reduction in the intracellular concentration of Zn²⁺ during epididymal transit allows the development of progressive motility and the subsequent hyper activated motility during sperm capacitation. Extracellular Zn²⁺ affects intracellular signaling pathways through its interaction with the Zn²⁺ sensing receptor (ZnR), also named GPR39. This receptor was found in the sperm tail and the acrosome, suggesting the possible involvement of Zn²⁺ in sperm motility and acrosomal exocytosis. Our studies showed that Zn²⁺ stimulates bovine sperm acrosomal exocytosis, as well as human sperm hyper-activated motility, were both mediated by GPR39. Zn²⁺ binds and activates GPR39, which activates the trans-membrane-adenylyl-cyclase (tmAC) to catalyze cAMP production. The NHE (Na⁺/H⁺-exchanger) is activated by cAMP, leading in increased pHi and activation of the sperm-specific Ca²⁺ channel CatSper, resulting in an increase in [Ca²⁺]_i, which, together with HCO₃⁻, activates the soluble adenylyl-cyclase (sAC). The increase in [cAMP]_i activates protein kinase A (PKA), followed by activation of the Src-epidermal growth factor receptor-Pphospholipase C (Src-EGFR-PLC) cascade, resulting in inositol-triphosphate (IP₃) production, which mobilizes Ca²⁺ from the acrosome, causing a further increase in [Ca²⁺]_i and the development of hyper-activated motility. PKA also activates phospholipase D1 (PLD1), leading to F-actin formation during capacitation. Prior to the acrosomal exocytosis, PLC induces phosphadidylinositol-4,5-bisphosphate (PIP₂) hydrolysis, leading to the release of the actin-severing protein gelsolin to the cytosol, which is activated by Ca²⁺, resulting in F-actin breakdown and the occurrence of acrosomal exocytosis.