From oxidative imbalance to compromised standard sperm parameters: Toxicological aspect of phthalate esters on spermatozoa

Glucose transporters (GLUTs): Underreported yet crucial molecules in unraveling testicular toxicity

Glucose transporters (GLUTs) are crucial in maintaining glucose homeostasis and supporting energy production in various tissues, including the testes. This review article delves into the distribution and function of GLUTs in distinct testicular cell types, namely Leydig cells, Sertoli cells, germ cells, and spermatozoa, shedding light on their significance in the context of male reproductive health-an issue of mounting global concern. Furthermore, this article examines the implications of GLUT dysregulation in testicular dysfunction. Altered GLUT expression has been associated with impaired steroidogenesis, spermatogenesis, sperm count, and motility in various animal models. Lastly, the article underscores the potential therapeutic implications of targeting GLUTs concerning testicular toxicity. Insights gleaned from studies in diabetes and cancer suggest that modulating GLUT expression and translocation could present novel strategies for mitigating testicular dysfunction and safeguarding male fertility. In summary, the intricate interplay between GLUTs, glucose metabolism, and testicular health underscores the significance of sustaining testicular glucose homeostasis for male reproductive health. Manipulating GLUTs presents an innovative avenue to address testicular dysfunction, potentially revolutionizing therapeutic strategies to restore male fertility and overall reproductive well-being. Future research in this field holds great promise for advancing male fertility treatments and reproductive health interventions.

Exposure to the plasticizer diisopentyl phthalate can cause Vero cell line death

Phthalates are synthetic plasticizers present in the daily lives of humans, as part of the composition of different products, such as food packaging, water bottles, and toys. These compounds can migrate from plastic materials to the environment changing biological systems. Although diisopentyl phthalate (DiPeP) is largely used in Brazil, there is a lack of information on the possible toxic effects of this compound. This research aims to evaluate the toxicity of DiPeP in the Vero renal cells. These cells were exposed to the 1-1000 μM of DiPeP for 24 and 72 h and subsequently, the cytotoxicity, apoptosis and necrosis-inducing potential, and antioxidant system (SOD, GPx, and GST) were investigated. DiPeP neither caused cytotoxicity nor altered SOD and GPx activity, although GST has been increased at 100 or 1 μM (24 and 72 h, respectively). However, cell death by apoptosis and necrosis was observed. These results indicate that DiPeP caused cell death by a non-oxidative stress-mediated mechanism, which shows the relevance of investigate other process in further researches.

Dibutyl phthalate disrupts glycogen synthase kinase 3α essential for sperm motility

To unravel the toxic mechanism of phthalate ester plasticizer endocrine disruptor in spermatozoa, we examined the effect of dibutyl phthalate (DBP) on the stability and inhibitory phosphorylation of glycogen synthase kinase 3α (GSK3α), a protein kinase crucial for sperm motility in mice. In DBP-treated spermatozoa, reactive oxygen species (ROS) and lipid peroxide were significantly increased. In computer-assisted sperm analysis, DBP at concentrations of 10 - 100 μg/mL significantly decreased total motility and progressive motility of spermatozoa. On western blots, DBP decreased p-GSK3α(Ser21) and increased p-GSK3α(Tyr279) in spermatozoa. Similarly, hydrogen peroxide decreased p-GSK3α(Ser21) but not p-GSK3α(Tyr279) in spermatozoa. Immunofluorescent labeling demonstrated that DBP markedly decreased immunoreactivities of GSK3α and p-GSK3α(Ser21) but increased immunoreactivity of p-GSK3α(Tyr279) in spermatozoa. DBP at a concentration of 100 μg/mL significantly increased phosphatase activity in spermatozoa. Calyculin A, a protein phosphatase 1 and 2 A inhibitor, markedly increased p-GSK3α(Ser21) and sperm motility and attenuated a DBP-induced decrease of p-GSK3α(Ser21) and sperm motility. On western blot, 1-100 μg/mL DBP decreased GSK3α in spermatozoa. On immunoprecipitation western blot, DBP at 10 - 100 μg/mL increased polyubiquitinated sperm proteins including GSK3α. The MG115, proteasome inhibitor attenuated degradation of GSK3α in DBP-treated spermatozoa. Hydrogen peroxide at 10 μM increased polyubiquitinated sperm proteins, suggesting that DBP may increase ubiquitination of GSK3α via ROS induction. Together, DBP may decrease the cellular amount of GSK3α through the ubiquitin-proteasome pathway and p-GSK3α(Ser21) through ROS generation and activation of protein phosphatases, impairing sperm motility.

Evaluation of precopulatory pairing behaviour and male fertility in a marine amphipod exposed to plastic additives

Plastics contain a mixture of chemical additives that can leach into the environment and potentially cause harmful effects on reproduction and the endocrine system. Two of these chemicals, N-butyl benzenesulfonamide (NBBS) and triphenyl phosphate (TPHP), are among the top 30 organic chemicals detected in surface and groundwater and are currently placed on international watchlist for evaluation. Although bans have been placed on legacy pollutants such as diethylhexyl phthalate (DEHP) and dibutyl phthalate (DBP), their persistence remains a concern. This study aimed to examine the impact of plastic additives, including NBBS, TPHP, DBP, and DEHP, on the reproductive behaviour and male fertility of the marine amphipod Echinogammarus marinus. Twenty precopulatory pairs of E. marinus were exposed to varying concentrations of the four test chemicals to assess their pairing behaviour. A high-throughput methodology was developed and optimised to record the contact time and re-pair time within 15 min and additional point observations for 96 h. The study found that low levels of NBBS, TPHP, and DEHP prolonged the contact and re-pairing time of amphipods and the proportion of pairs reduced drastically with re-pairing success ranging from 75% to 100% in the control group and 0%-85% in the exposed groups at 96 h. Sperm count declined by 40% and 60% in the 50 μg/l and 500 μg/l DBP groups, respectively, whereas TPHP resulted in significantly lower sperms in 50 μg/l exposed group. Animals exposed to NBBS and DEHP showed high interindividual variability in all exposed groups. Overall, this study provides evidence that plastic additives can disrupt the reproductive mechanisms and sperm counts of amphipods at environmentally relevant concentrations. Our research also demonstrated the usefulness of the precopulatory pairing mechanism as a sensitive endpoint in ecotoxicity assessments to proactively mitigate population-level effects in the aquatic environment.

Carvacrol showed a curative effect on reproductive toxicity caused by Bisphenol AF via antioxidant, anti-inflammatory and anti-apoptotic properties

Bisphenol AF (BPAF) is an endocrine disruptor, and human exposure to these chemicals is growing in industrialized nations. BPAF has been demonstrated in studies to have toxic effects on reproductive health. This study examined the effects of oral exposure to BPAF on the reproductive system and the protective effects of carvacrol in rats. From 32 Wistar albino rats, four separate groups were set up for this purpose. Carvacrol 75 mg/kg and BPAF 200 mg/kg were administered by oral gavage method. Rat sperm parameters and serum testosterone levels were measured after 28 days of administration. The study looked at the MDA in the testis tissues, as well as CAT, GPx, and GSH as antioxidants parameters, NF-κB and TNF-α as inflammatory markers, caspase-3 and Bcl-2 as apoptosis parameters, and PCNA as cell proliferation markers. In addition, testis tissues underwent histological evaluation. As a result, in rats exposed to only BPAF, sperm counts declined, testosterone levels reduced, oxidative stress, inflammation, and apoptosis increased, and cell proliferation decreased. Furthermore, severe disruptions in tissue architecture and decreased spermatogenesis were reported. In contrast, sperm parameters improved, testosterone levels increased, oxidative stress and inflammation decreased, and apoptosis was prevented in the carvacrol-treated group compared to the BPAF-only group. It was also found that spermatogenesis was maintained, and structural abnormalities in testicular tissue were mostly avoided with an increase in PCNA expression. According to the findings, despite BPAF-induced testicular and reproductive toxicity, carvacrol had therapeutic potential due to its anti-inflammatory, antioxidant, cell proliferation-increasing, and anti-apoptotic activities.