Bisphenol A (BPA) is an endocrine-disrupting chemical that is toxic to reproduction. Zinc (Zn) plays an important role in male reproductive health. Zn deficiency (ZD) can co-exist with BPA. In order to investigate the specific mechanism of reproductive damage caused by BPA exposure in ZD male mice, a mouse model of ZD, BPA exposure, and their combined exposure was established in this study. Forty 4-week-old SPF male ICR mice with an average body weight of 31.7 ± 4.2 g were divided into four groups including normal Zn diet group 30 mg/(kg•d), BPA exposure group 150 mg/(kg•d), zinc deficiency diet group 7.5 mg/(kg•d), and BPA + ZD combined exposure group (BPA 150 mg/(kg•d) + ZD 7.5 mg/(kg•d)). The mice were kept for 8 weeks. The results showed that the testicular tissue structure was disturbed, and semen quality, serum Zn, testicular tissue Zn, and testicular tissue free Zn ions were decreased in the BPA-exposed and ZD groups. The expression of zinc transporters (ZIP7, ZIP8, ZIP13, and ZIP14) in testicular tissue was changed. The expressions of pro-inflammatory cytokines including TNF-α and IL-1β as well as inflammatory pathway–related proteins (IKB-α, p-IKB-α, NF-κB, p-NF-κB, Caspase8, and Caspase3) were increased, while the expressions of anti-inflammatory cytokines (TGF-β and IL-10) were decreased. The changes in the above indexes in the BPA + ZD group were more obvious. Both BPA exposure and ZD can induce testicular tissue inflammation through the TNF-α/NF-κB/Caspase8 signaling pathway, and BPA further aggravates zinc deficiency–induced testicular tissue inflammation and apoptosis damage.

Diabetes increases the likelihood of germ cell damage, hypogonadism, and male infertility. Diabetes leads to lower zinc (Zn) levels, an important micronutrient for maintaining male fertility, and zinc deficiency can lead to decreased male fertility through multiple mechanisms. The aim of this study was to investigate the effect of combined metformin and zinc administration on epididymis in diabetic mice; 10 of 50 male mice were randomly selected as the control group (group C), and the remaining 40 mice were randomly divided into untreated diabetes group (group D), diabetes + zinc group (group Z), diabetes + metformin group (group M), and diabetes + metformin + zinc group (group ZM) with 10 mice each. Diabetic mice in group Z received oral zinc (10 mg/kg) once daily for 4 weeks; diabetic mice in group M received oral metformin (200 mg/kg) once daily for 4 weeks; diabetic mice in group ZM received oral metformin and zinc once daily for 4 weeks; and groups C and D received the same amount of sterile water by gavage. Overnight fasted mice were sacrificed, and blood samples, mouse epididymides, and sperm were collected for further experiments. In group D, fasting blood glucose and insulin resistance index increased significantly, semen quality, serum insulin, and testosterone decreased, and epididymal structure was disordered. In group D, epididymal tissue zinc, free zinc ions in the caput, and cauda of epididymis and zinc transporter (ZnT2) decreased significantly, while ZIP12, metallothionein (MT), and metal transcription factor (MTF1) increased significantly. In addition, the expressions of blood-epididymal barrier (BEB)-related molecules (including ZO-1 β-catenin and N-cadherin) and aquaporins (AQPs, including AQP3, AQP9, and AQP11) in the epididymis of mice in group D were significantly decreased. In addition, compared with groups D, Z, and M, in the ZM group, the expression of BEB-related molecules (including ZO-1, β-catenin, and N-cadherin) and aquaporins (AQP3, AQP9, and AQP11) in epididymis tissue were significantly increased, and sperm motility and serum testosterone were significantly increased. It was concluded that male diabetic mice have a disturbed epididymal structure and decreased semen quality by causing an imbalance in epididymal zinc homeostasis, BEB, and impaired absorptive function. The combination of zinc and metformin is an effective and safe alternative treatment and provides additional benefits over metformin alone.

Zinc is an essential trace element crucial for growth and development and plays a significant role in male reproductive function. The aim of this study was explore the mechanism of male reproductive damage caused by different degrees of zinc deficiency. Thirty male ICR mice were randomly assigned to three groups: zinc-normal diet group (ZN, n = 10, Zn content = 30 mg/kg), low zinc-deficiency diet group (LZD, n = 10, Zn content = 15 mg/kg), and high zinc-deficiency diet group (HZD, n = 10, Zn content = 7.5 mg/kg). The mice were maintained for 8 weeks. At the end of the experiment, they were sacrificed, and their blood, testicular, and epididymal tissues were collected for further study. Zinc-deficient diet led to weight loss, testicular structural disorder, decreased semen quality, imbalance of zinc homeostasis, and inflammatory damage in mice. Semen quality, testosterone, serum Zn, testicular tissue Zn, testicular free Zn ions, Zrt-, Irt-like protein8 (ZIP8), Zrt-, Irt-like protein5 (ZIP5), and interleukin-10 (IL-10) were significantly decreased; zinc transporter 4(ZnT4), NF-κB p65, P-NF-κB p65, NLRP3, Caspase-8, and Caspase-3 were significantly increased in both LZD and HZD group mice. While compared with the LZD group, Zrt-, Irt-like protein13 (ZIP13), TNF-α, NF-κB p65, P-NF-κB p65, NLRP3, Caspase-1, and GSDMD were significantly increased in the HZD group. Both low and high zinc-deficiency diets can disrupt zinc homeostasis in mice, leading to heightened inflammatory responses, the activation of the NF-κB pathway, and increased apoptosis in testicular cells. Notably, a high zinc-deficiency diet led to an up-regulation of ZIP13 expression, exacerbated inflammation, and induced testicular pyroptosis, resulting in more severe reproductive damage in male mice.

Bisphenol A (BPA) is a contaminant widely found in food packaging that can reduce sperm quality and impair male fertility. Zinc (Zn) is an important antioxidant involved in many important biological functions. The aim of this study was to explore the protective effect and mechanism of Zn on reproductive toxicity induced by BPA. Male ICR mice were divided into a control group, a BPA group and a BPA + Zn group. The results showed that the body weight, sperm count and sperm motility of the animals in the BPA group were significantly reduced, and testicular structure was damaged. BPA decreased the levels of serum total Zn, testis-free zinc, ADH and ALP, upregulated the expression of ZnT4 protein, and down-regulated the expression levels of ZIP8, ZIP14, ZnT1, MT and MTF1 protein, resulting in the imbalance of testicular Zn homeostasis. BPA down-regulates the antioxidant enzymes SOD and GSH-Px, and increases MDA, leading to oxidative stress. BPA up-regulates TF, TFR and STEAP3 and down-regulates SLC7A11, GPX4, FPN1 and FTH protein levels, resulting in abnormal iron metabolism and ferroptosis. BPA down-regulated anti-apoptotic protein Bcl-2, up-regulated pro-apoptotic markers Bax, caspase-9, caspase-8 and caspase-3, and induced apoptosis. BPA also increased the phosphorylation of JNK and ERK1/2, but did not increase the phosphorylation of P38. Zn significantly increased body weight and sperm quality, improved testicular morphology, down-regulated p-JNK/JNK and p-ERK/ERK levels, improved oxidative stress, and reduced ferroptosis and apoptosis. In conclusion, Zn regulates Zn homeostasis and down-regulates the MAPK signaling pathway, thereby inhibiting ferroptosis and apoptosis, alleviating BPA-induced oxidative stress and ultimately improving male reproductive damage.

The long-term use of tripterygium glycosides (TG) can lead to male reproductive damage. Research indicates that zinc and selenium exhibit a synergistic effect in the male reproductive system, with the combined preparation demonstrating superior therapeutic effects compared to individual preparations. The purpose of this study was to explore the specific mechanism by which zinc and selenium mitigate reproductive toxicity induced by TG in male rats. Rats were randomly assigned to three groups: control group (C group), model group (M group, receiving TG at 30 mg/kg/day), and model + zinc + selenium group (ZS group). The ZS group was also given TG gavage for the first 4 weeks. Starting from the fifth week until the conclusion of the eighth week, the ZS group received an additional protective treatment of 10 mg/kg/day Zn and 0.1 mg/kg/day Se 4 h after TG administration. Following euthanasia, blood samples, rat testis, and epididymis tissues were collected for further experiments. Combined zinc-selenium treatment corrects the imbalance of zinc-selenium homeostasis in testicular tissue induced by TG. This is achieved by upregulating the expression of metal transcription factor (MTF1) and zinc transporters ZIP8 and ZIP14 and downregulating the expression of ZnT10. Improvement of zinc and selenium homeostasis enhanced the expression of zinc-containing enzymes (ADH, LDH, and ALP) and selenoproteins (GPx1 and SELENOP) in the testis. At the same time, zinc and selenium mitigate TG-induced reproductive damage by promoting the activity of antioxidant enzymes and upregulating the expression of proteins associated with the oxidative stress pathway, including Nrf2, Keap1, HO-1, PI3K, and p-AKT.

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.

目的 探讨高脂饮食诱导肥胖大鼠睾丸组织差异表达的环状RNAs(circRNA)及微小 RNA(miRNA).方法 通过高脂饲料构建肥胖大鼠模型,HE染色观察睾丸组织病理学变化,检测精子浓度、活力、DFI 和 CMA3+,高通量测序筛选肥胖大鼠睾丸组织差异表达的circRNAs及miRNAs,通过GO和KEGG分析其参与的主要生物学过程,最后构建 circRNA-miRNA-mRNA网络.结果 与正常组相比,肥胖组大鼠睾丸组织结构改变,精子浓度、活力显著降低(P<0.05),DFI、CMA3+显著升高(P<0.05).芯片筛选出肥胖组大鼠睾丸组织有 32 个差异表达的circRNAs和4 个差异表达的miRNAs.生物信息学分析显示这些基因可能通过Wnt信号通路、TNF信号通路和胰岛素分泌等通路调控肥胖引起的雄性生殖障碍.筛选差异显著且具有靶向关系的circRNA和miRNA:novel_circ_0003226/rno-miR-3544、novel_circ_0015575/rno-miR-9a-5p,并构建circRNA-miRNA-mRNA网络.结论 肥胖大鼠睾丸组织存在差异表达的circRNAs和miRNAs,这些差异基因可能通过circRNA-miRNA-mRNA网络调控肥胖引起的雄性大鼠生殖障碍.

目的 鉴定高尿酸血症模型大鼠睾丸组织中差异表达的长链非编码RNA(lncRNA).方法 苏木素伊红(HE)染色法观察大鼠睾丸组织病理形态,从对照组和高尿酸血症组雄性SD大鼠睾丸组织中分别提取RNA进行测序,筛选出两组间差异表达的lncRNA,对其进行靶基因预测,并将lncRNA和mRNA进行GO和KEGG功能富集分析.结果 高尿酸血症组睾丸组织结构受损.与对照组相比,筛选获得差异表达的lncRNA有89个(上调42个、下调47个);差异表达mRNA有50个(上调29个、下调21个).GO富集分析结果显示,这些差异表达lncRNA主要与胰岛素受体信号通路的调节、炎症反应的调节、发育过程及G-蛋白偶联谷氨酸受体结合相关.KEGG通路富集分析结果显示,差异表达lncRNA主要富集在胰岛素信号通路、cGMP-PKG信号通路、cAMP信号通路及钙信号通路上.结论 高尿酸血症大鼠睾丸组织中lncRNA的表达有差异,有助于阐明lncRNA在高尿酸血症导致雄性大鼠生殖障碍的潜在作用.

Zinc deficiency has a huge impact on male reproduction. The zinc transporter (ZnT) family is involved in the maintenance of zinc homeostasis and testosterone synthesis. However, the underlying mechanisms remain to be investigated. Therefore, in this study, we aimed to determine the effect of zinc transporter 4 (ZnT4) on testosterone synthesis in male Kunming mice and mouse Leydig cells. The results of this study showed that compared with the zinc normal diet group (Con group), the zinc-deficient diet group (ZnD group) had decreased zinc content and increased ZnT4 expression in testicular tissues, and decreased serum testosterone levels, suggesting that ZnT4 may be involved in Leydig cell injury resulting from a zinc-deficient diet. Subsequently, mouse Leydig cell line TM3 cells were used to analyze the effect of ZnT4 downregulation on TM3 cell proliferation and apoptosis, on testosterone synthesis, and its underlying mechanisms. Here, we show that knockdown of ZnT4 can induce the accumulation of zinc, inhibit the viability, and induce apoptosis in TM3 cells. In addition, knockdown of ZnT4 downregulated testosterone concentration and expression of testosterone synthesis–related proteins steroidogenic acute regulatory protein (StAR) and 3β-hydroxysteroid dehydrogenase/D5-D4 isomerase (3β-HSD) in TM3 cells, while hCG could rescue their levels. We show that it is ZnT4 that plays a role in testosterone production through a mediated PI3K/Akt/mTOR autophagy pathway, whereas mTORC1 complex inhibitor (Rapa) blocks the decrease in testosterone levels caused by ZnT4 downregulation. In conclusion, the above results indicate that ZnT4 plays an important role in regulating testosterone synthesis.