Bisphenol A (BPA) induces apoptosis of mouse Leydig cells via oxidative stress

Zinc Attenuates Bisphenol A-Induced Reproductive Toxicity in Male Mice by Inhibiting Ferroptosis and Apoptosis Through Improving Zinc Homeostasis

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.

BPA induces testicular damage in male rodents via apoptosis, autophagy, and ferroptosis

Bisphenol A (BPA), chemically known as 2,2-bis(4-hydroxyphenyl) propane, is one of the most common endocrine-disrupting chemicals in our environment. Long-term or high-dose exposure to BPA may lead to testicular damage and adversely affect male reproductive function. In vivo studies on rodents have demonstrated that BPA triggers apoptosis in testicular cells through both intrinsic and extrinsic pathways. Further in vitro studies on spermatogonia, Sertoli cells, and Leydig cells have all confirmed the pro-apoptotic effects of BPA. Given these findings, apoptosis is considered a primary mode of cell death induced by BPA in testicular tissue. In addition, BPA promotes autophagy by altering the activity of the Akt/mTOR pathway and upregulating the expression of autophagy-related genes and proteins. Recent studies have also identified ferroptosis as a significant contributing factor to BPA-induced testicular damage, further complicating the landscape of BPA's effects. This review summarizes natural substances that mitigate BPA-induced testicular damage by inhibiting these cell death pathways. These findings not only highlight potential therapeutic strategies but also underscore the need for further research into the underlying mechanisms of BPA-induced toxicity, particularly as it pertains to human health risk assessment and the development of more effective BPA management strategies.

Enhanced endoplasmic reticulum stress signaling disrupts porcine sertoli cell function in response to Bisphenol A exposure

Bisphenol A (BPA), a pervasive substance in our daily lives and livestock excreta, poses significant threats due to its infiltration into foods and water sources. BPA has adverse impacts on male reproductive function, particularly affecting the critical Sertoli (ST) cells that play a pivotal role in the process of spermatogonia differentiating into spermatozoa. In this study, we examined the prevalence of BPA within the pig industry and delved into the impact of BPA exposure on the motility of boar sperm, the function of pig ST cells, as well as the underlying molecular mechanisms involved. This study revealed spatial disparities in the global distribution of BPA and its analogue contamination, utilizing data compiled from 130 comprehensive studies. The average concentration of BPA found in pig feed ranges from 9.7 to 47.9 μg/kg, while in serum, it averages between 55.1 and 75.6 ng/L. The BPA concentration in feed exhibits a negative correlation with sperm viability and the percentage of progressive motile spermatozoa. Exposure to BPA reduced sperm motility in boar and ST cell activity at both 6 and 24 h. The transcriptome analysis revealed that, compared to untreated control cells, endoplasmic reticulum stress (ERS)-related genes were upregulated in ST cells exposed to BPA at 6 and 24 h. This activation of ERS in ST cells was mediated by receptor protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring protein-1α (IRE1α), and activating transcription factor 6 (ATF6). Additionally, BPA exposure triggered oxidative stress and a proinflammatory response mediated by the transcription factor NF-κB, accompanied by an increase in downstream proinflammatory cytokines. BPA exposure also led to apoptosis in ST cells and upregulated the expression levels of pro-apoptosis proteins. However, inhibiting ERS activity with 4-PBA attenuated the BPA-induced inflammatory response and apoptosis in ST cells. Our findings suggest that BPA induced apoptosis and inflammatory response in porcine ST cells through persistent activation of ERS, thereby compromising the normal function of these cells.

Coexposure to microplastic and Bisphenol A exhacerbates damage to human kidney proximal tubular cells

Microplastics (MPs) accumulate in tissues, including kidney tissue, while Bisphenol A (BPA) is a plasticizer of particular concern. At present, the combined effects of MPs and BPA are unexplored in human renal cells. Therefore, we exposed a proximal tubular cell line (PTECs) to polyethylene (PE)-MPs and BPA, both separately and in combination. When co-exposed, cells showed a significantly reduced cell viability (MTT test) and a pronounced pro-oxidant (MDA levels, NRF2 and NOX4 expression by Western blot) and pro-inflammatory response (IL1β, CCL/CCR2 and CCL/CCR5 mRNAs by RT-PCR), compared to those treated with a single compound. In addition, heat shock protein (HSP90), a chaperone involved in multiple cellular functions, was reduced (by Western Blot and immunocytochemistry), while aryl hydrocarbon receptor (AHR) expression, a transcription factor which binds environmental ligands, was increased (RT-PCR and immunofluorescence). Our research can contribute to the study of the nephrotoxic effects of pollutants and MPs and shed new light on the combined effects of BPA and PE-MPs.

Potential hazards of bisphenol A on the male reproductive system: Induction of programmed cell death in testicular cells

A common industrial chemical known as bisphenol A (BPA) has been linked to endocrine disruption and can interfere with hormonal signaling pathways in humans and animals. This comprehensive review aims to explore the detrimental consequences of BPA on reproductive organ performance and apoptosis induction, shedding light on the emerging body of evidence from laboratory animal studies. Historically, most studies investigating the connection between BPA and reproductive tissue function have mainly leaned on laboratory animal models. These studies have provided crucial insights into the harmful effects of BPA on several facets of reproduction. This review consolidates an increasing literature that correlates exposure to BPA in the environment with a negative impact on human health. It also integrates findings from laboratory studies conducted on diverse species, collectively bolstering the mounting evidence that environmental BPA exposure can be detrimental to both humans and animals, particularly to reproductive health. Furthermore, this article explores the fundamental processes by which BPA triggers cell death and apoptosis in testicular cells. By elucidating these mechanisms, this review aids a deeper understanding of the complex interactions between BPA and reproductive tissues.

A comprehensive review on potential role of selenium, selenoproteins and selenium nanoparticles in male fertility

Selenium (Se), a component of selenoproteins and selenocompounds in the human body, is crucial for the development of male reproductive organs, DNA synthesis, thyroid hormone, metabolism, and defence against infections and oxidative damage. In the testis, it must exceed a desirable level since either a shortage or an overabundance causes aberrant growth. The antioxidant properties of selenium are essential for preserving human reproductive health. Selenoproteins, which have important structural and enzymatic properties, control the biological activities of Se primarily. These proteins specifically have a role in metabolism and a variety of cellular processes, such as the control of selenium transport, thyroid hormone metabolism, immunity, and redox balance. Selenium nanoparticles (SeNPs) are less hazardous than selenium-based inorganic and organic materials. Upon being functionalized with active targeting ligands, they are both biocompatible and capable of efficiently delivering combinations of payloads to particular cells. In this review, we discuss briefly the chemistry, structure and functions of selenium and milestones of selenium and selenoproteins. Next we discuss the various factors influences male infertility, biological functions of selenium and selenoproteins, and role of selenium and selenoproteins in spermatogenesis and male fertility. Furthermore, we discuss the molecular mechanism of selenium transport and protective effects of selenium on oxidative stress, apoptosis and inflammation. We also highlight critical contribution of selenium nanoparticles on male fertility and spermatogenesis. Finally ends with conclusion and future perspectives.

Health risks of Bisphenol-A exposure: From Wnt signaling perspective

Human beings are routinely exposed to chronic and low dose of Bisphenols (BPs) due to their widely pervasiveness in the environment. BPs hold similar chemical structures to 17β-estradiol (E2) and thyroid hormone, thus posing threats to human health by rendering the endocrine system dysfunctional. Among BPs, Bisphenol-A (BPA) is the best-known and extensively studied endocrine disrupting compound (EDC). BPA possesses multisystem toxicity, including reproductive toxicity, neurotoxicity, hepatoxicity and nephrotoxicity. Particularly, the central nervous system (CNS), especially the developing one, is vulnerable to BPA exposure. This review describes our current knowledge of BPA toxicity and the related molecular mechanisms, with an emphasis on the role of Wnt signaling in the related processes. We also discuss the role of oxidative stress, endocrine signaling and epigenetics in the regulation of Wnt signaling by BPA exposure. In summary, dysfunction of Wnt signaling plays a key role in BPA toxicity and thus can be a potential target to alleviate EDCs induced damage to organisms.

Enniatin B1 induces damage to Leydig cells via inhibition of the Nrf2/HO-1 and JAK/STAT3 signaling pathways

Enniatin B1 (ENN B1) is a mycotoxin that can be found in various foods. However, whether ENN B1 is hazardous to the reproductive system is still elusive. Leydig cells are testosterone-generating cells that reside in the interstitial compartment between seminiferous tubules. Dysfunction of Leydig cells could result in male infertility. This study aimed to examine the toxicological effects of ENN B1 against TM3 Leydig cells. ENN B1 significantly inhibited cell viability in a dose-dependent manner. ENN B1 treatment also decreased the expression of functional genes in Leydig cells. Moreover, ENN B1 induced Leydig cells apoptosis and oxidative stress. Mechanistically, ENN B1 leads to the upregulation of Bax and downregulation of Bcl-2 in Leydig cells. In addition, ENN B1 inhibited the Nrf2/HO-1 pathway, which is critical for the induction of oxidative stress. Additionally, ENN B1 treatment repressed the JAK/STAT3 signaling pathway in Leydig cells. Rescue experiments showed that activation of STAT3 resulted in alleviation of ENN B1-induced damage in Leydig cells. Collectively, our study demonstrated that ENN B1 induced Leydig cell dysfunction via multiple mechanisms.

Melatonin alleviates oxidative stress damage in mouse testes induced by bisphenol A

We investigated the effect of melatonin on bisphenol A (BPA)-induced oxidative stress damage in testicular tissue and Leydig cells. Mice were gavaged with 50 mg/kg BPA for 30 days, and concurrently, were injected with melatonin (10 mg/kg and 20 mg/kg). Leydig cells were treated with 10 μmol/L of BPA and melatonin. The morphology and organ index of the testis and epididymis were observed and calculated. The sperm viability and density were determined. The expressions of melatonin receptor 1A and luteinizing hormone receptor, and the levels of malonaldehyde, antioxidant enzymes, glutathione, steroid hormone synthases, aromatase, luteinizing hormone, testosterone, and estradiol were measured. TUNEL assay was utilized to detect testicular cell apoptosis. The administration of melatonin at 20 mg/kg significantly improved the testicular index and epididymis index in mice treated with BPA. Additionally, melatonin promoted the development of seminiferous tubules in the testes. Furthermore, the treatment with 20 mg/kg melatonin significantly increased sperm viability and sperm density in mice, while also promoting the expressions of melatonin receptor 1A and luteinizing hormone receptor in Leydig cells of BPA-treated mice. Significantly, melatonin reduced the level of malonaldehyde in testicular tissue and increased the expression of antioxidant enzymes (superoxide dismutase 1, superoxide dismutase 2, and catalase) as well as the content of glutathione. Moreover, melatonin also reduced the number of apoptotic Leydig cells and spermatogonia, aromatase expression, and estradiol level, while increasing the expression of steroid hormone synthases (steroidogenic acute regulatory protein, cytochrome P450 family 17a1, cytochrome P450 17α-hydroxylase/20-lyase, and, 17β-hydroxysteroid dehydrogenase) and the level of testosterone. Melatonin exhibited significant potential in alleviating testicular oxidative stress damage caused by BPA. These beneficial effects may be attributed to melatonin's ability to enhance the antioxidant capacity of testicular tissue, promote testosterone synthesis, and reduce testicular cell apoptosis.

ARTS is essential for di-2-ethylhexyl phthalate (DEHP)-induced apoptosis of mouse Leydig cells

As an extensively employed plasticizer in industrial applications, di-2-ethylhexyl phthalate (DEHP) can induce apoptosis of mouse Leydig cells, yet the precise mechanism remains elusive. In the current study, we identified that DEHP could specially induced apoptosis in the Leydig cells of the testis tissue, accompanied with the upregulation of apoptosis-related protein in the TGF-β signaling pathway (ARTS) in the cells. Overexpression of ARTS significantly induced apoptosis of TM3 cells, while knockdown of ARTS inhibited apoptosis. Furthermore, DEHP-induced apoptosis of TM3 cells could be alleviated by knockdown of ARTS, which indicated that ARTS was involved in DEHP-induced apoptosis of mouse Leydig cells. Bioinformation assay predicts that there are four potential p53-responsive elements (p53-REs) located at - 6060, - 5726, - 5631 and - 5554 before the transcription start site of ARTS gene, implying that gene transcription of ARTS could be regulated by p53. Interestingly, DEHP was shown to specifically upregulate the expression of p53 in the Leydig cells of the testis tissue and TM3 cells. Consistently, p53 was proved to bind to the RE4 site of the ARTS gene promoter and transcriptionally activated the promoter-driven expression of the luciferase reporter gene. Overexpression of p53 could induce apoptosis of TM3 cells; while knockdown of p53 could not only rescue DEHP-induced apoptosis of the cells, but also inhibit DEHP-caused upregulation of ARTS. Meanwhile, we showed that oxidative stress could induce apoptosis of TM3 cells, accompanied with the increased protein levels of p53 and ARTS; while inhibition of oxidative stress dramatically alleviated DEHP-induced apoptosis and the up-regulation of p53 and ARTS. Taken together, these results indicated that DEHP-induced oxidative stress activates the p53-ARTS cascade to promote apoptosis of mouse Leydig cells.

DDIT4 is essential for DINP-induced autophagy of ovarian granulosa cells

As one of the most important phthalates, di-isononyl phthalate (DINP) has been widely used as a common plasticizer in the food and personal care products sectors. In our previous study, we found that DINP can induce autophagy of ovarian granulosa cells; while the underlying mechanism is unclear. In the study, we showed that DINP exposure could induce autophagy of ovarian granulosa cells and KGN cells, accompanied with the increase in the mRNA and protein level of DDIT4. Furthermore, overexpression of DDIT4 were shown to induce autophagy of KGN cells; while knockdown of DDIT4 inhibited DINP-induced autophagy, implying that DDIT4 played an important role in DINP-induced autophagy of ovarian granulosa cells. There were three putative binding sites of transcription factor ATF4 in the promoter region of DDIT4 gene, suggesting that DDIT4 might be regulated by ATF4. Herein, we found that overexpression of ATF4 could upregulate the expression of DDIT4 in KGN cells, while knockdown of ATF4 inhibited its expression. Subsequently, ATF4 was identified to bind to the promoter region of DDIT4 gene and promote its transcription. The expression of ATF4 was also increased in the DINP-exposed granulosa cells, and ATF4 overexpression promoted autophagy of KGN cells; whereas knockdown of ATF4 alleviated DINP-induced upregulation of DDIT4 and autophagy of the cells. Taken together, DINP triggered autophagy of ovarian granulosa cells through activating ATF4/DDIT4 signals.

Hepatoprotective effect of Artemisia Argyi essential oil on bisphenol A-induced hepatotoxicity via inhibition of ferroptosis in mice

The environmental pollutant bisphenol A (BPA), used in the manufacture of plastic packaging materials for various diets, is widely distributed in the environment and causes severe hepatotoxicity by inducing oxidative stress. Artemisia argyi essential oil (AAEO), a volatile oil component isolated from Artemisia argyi H.Lév. & Vaniot, has pharmacological effects, especially for hepatoprotective actions. However, the potential effect of AAEO in BPA induced hepatotoxicity has not been characterized. First, we analyzed the chemical composition in AAEO by gas chromatography-mass spectrometry. Herein, we investigated the effect of AAEO on hepatic metabolic changes in mice exposed to BPA. Results showed that compared with the BPA group, AAEO could reduce the level of liver function enzymes in BPA mice serum, and ameliorate hepatic lesions and fibrosis. Additionally, 20 differential metabolites screened by metabolomics were mainly involved in the reprogramming of glutathione metabolism, purine metabolism, and polyunsaturated fatty acid synthesis. Moreover, AAEO could reduce hepatic ferroptosis induced by BPA, as demonstrated by reducing xanthine oxidase activity, up-regulating the activities of glutathione peroxidase 4 (GPX4), superoxide dismutase, and catalase and the expression of SLC7A11 to promote the glutathione synthetic, while inhibiting transferrin receptor 1 (TFR1) expression to reduce the accumulation of Fe2+ in cells. Therefore, our study identified AAEO as a hepatic protectant against BPA-induced hepatotoxicity by reversing the occurrence of ferroptosis.

Protective Effects of Selenium Nanoparticles against Bisphenol A-Induced Toxicity in Porcine Intestinal Epithelial Cells

Bisphenol A (BPA) is widely used to harden plastics and polycarbonates and causes serious toxic effects in multiple organs, including the intestines. Selenium, as an essential nutrient element for humans and animals, exhibits a predominant effect in various physiological processes. Selenium nanoparticles have attracted more and more attention due to their outstanding biological activity and biosafety. We prepared chitosan-coated selenium nanoparticles (SeNPs) and further compared the protective effects, and investigated the underlying mechanism of SeNPs and inorganic selenium (Na₂SeO₃) on BPA-induced toxicity in porcine intestinal epithelial cells (IPEC-J2). The particle size, zeta potential, and microstructure of SeNPs were detected by using a nano-selenium particle size meter and a transmission electron microscope. IPEC-J2 cells were exposed to BPA alone or simultaneously exposed to BPA and SeNPs or Na₂SeO₃. The CCK8 assay was performed to screen the optimal concentration of BPA exposure and the optimal concentration of SeNPs and Na₂SeO₃ treatment. The apoptosis rate was detected by flow cytometry. Real-time PCR and Western blot methods were used to analyze the mRNA and protein expression of factors related to tight junctions, apoptosis, inflammatory responses and endoplasmic reticulum stress. Increased death and morphological damage were observed after BPA exposure, and these increases were attenuated by SeNPs and Na₂SeO₃ treatment. BPA exposure disturbed the tight junction function involved with decreased expression of tight junction protein Zonula occludens 1 (ZO-1), occludin, and claudin-1 proteins. Proinflammatory response mediated by the transcription factor nuclear factor-k-gene binding (NF-κB), such as elevated levels of interleukin-1β(IL-1β), interleukin-6 (IL-6), interferon-γ (IFN-γ), interleukin-17 (IL-17), and tumor necrosis factor-α (TNF-α) expression was induced at 6 and 24 h after BPA exposure. BPA exposure also disturbed the oxidant/antioxidant status and led to oxidative stress. IPEC-J2 cell apoptosis was induced by BPA exposure, as indicated by increased BCL-2-associated X protein (Bax), caspase 3, caspase 8, and caspase 9 expression and decreased B-cell lymphoma-2 (Bcl-2) and Bcl-xl expression. BPA exposure activated the endoplasmic reticulum stress (ERS) mediated by the receptor protein kinase receptor-like endoplasmic reticulum kinase (PERK), Inositol requiring enzyme 1 (IRE1α), and activating transcription factor 6 (ATF6). We found that treatment with SeNPs and Na₂SeO₃ can alleviate the intestinal damage caused by BPA. SeNPs were superior to Na₂SeO₃ and counteracted BPA-induced tight junction function injury, proinflammatory response, oxidative stress, apoptosis, and ERS stress. Our findings suggest that SeNPs protect intestinal epithelial cells from BPA-induced damage, partly through inhibiting ER stress activation and subsequently attenuating proinflammatory responses and oxidative stress and suppressing apoptosis, thus enhancing the intestinal epithelial barrier function. Our data indicate that selenium nanoparticles may represent an effective and reliable tool for preventing BPA toxicity in animals and humans.