The morphological consequences of chronic exposition to low doses of cadmium (Cd) in the Leydig cells population were investigated in 40 sexually mature male mice at morphological and ultrastructural levels. Animals were orally exposed to cadmium (0.015 g/L of CdCl(2) in drinking water) for 3, 6, 12 and 18 months and then sacrificed, samples were collected for toxicological, light and electron microscope studies. Vascular lesions were evident from 6 months of Cd exposure, the severity of the morphological changes observed in the testicular vases were highly and clearly correlated to the time of exposure to Cd. The severity of the Leydig cells morphological changes were increasing along the time of exposure. Presence of cytoplasm vacuolization and degenerative images of the cells were frequent after 12 months of Cd exposure. Also two Leydig cells tumours after 12 and 18 months Cd exposure were presented. These results indicate that prolonged exposures to low doses of Cd are able to induce morphological damage on the Leydig cells.

Bisphenol A (BPA) is a chemical substance commonly used in the manufacture of plastic products. Its inhalation or ingestion from particles in suspension, water, and/or polluted foods can trigger toxic effects related to endocrine disruption, resulting in hormonal, reproduction, and immunological alterations in humans and animals. The zebrafish (Danio rerio) is an ideal experimental model frequently used in toxicity studies. In order to assess the toxic effects of BPA on reproduction and embryonic development in one generation after parental exposure to it, a total of 80 zebrafish, males and females, divided into four groups in duplicate (n = 20) were exposed to BPA concentrations of 500, 50, and 5 µg L−1, along with a control group. The fish were kept in reproduction aquariums for 21 days. The embryos obtained in the crosses were incubated in a BPA-free medium and observed for signs of embryotoxicity. A histopathological study (under optical and electron microscopes) was performed of adult fish gonads. The embryos of reproducers exposed to BPA were those most frequently presenting signs of embryotoxicity, such as mortality and cardiac and musculoskeletal malformations. In the histopathological studies of adult individuals, alterations were found in ovocyte maturation and in spermatazoid formation in the groups exposed to the chemical. Those alterations were directly related to BPA action, affecting fertility in both sexes, as well as the viability of their offspring, proportionally to the BPA levels to which they were exposed, so that our results provide more information by associating toxic effects on the offspring and on the next generation.

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Bisphenol A (BPA) is a chemical compound, considered as an “emerging pollutant”, that appears ubiquitously, contaminating the environment and food. It is an endocrine disruptor, found in a multitude of consumer products, as it is a constituent of polycarbonate used in the manufacture of plastics and epoxy resins. Many studies have evaluated the effects of BPA, using a wide range of doses and animal models. In this work, we carried out a review of relevant research related to the effects of BPA on health, through studies performed at different doses, in different animal models, and in human monitoring studies. Numerous effects of BPA on health have been described; in different animal species, it has been reported that it interferes with fertility in both females and males and causes alterations in their offspring, as well as being associated with an increase in hormone-dependent pathologies. Similarly, exposure to BPA has been related to other diseases of great relevance in public health such as obesity, hypertension, diabetes, or neurodevelopmental disorders. Its ubiquity and nonmonotonic behavior, triggering effects at exposure levels considered “safe”, make it especially relevant when both animal and human populations are constantly and inadvertently exposed to this compound. Its effects at low exposure levels make it essential to establish safe exposure levels, and research into the effects of BPA must continue and be focused from a “One Health” perspective to take into account all the factors that could intervene in the development of a disease in any exposed organism.

Bisphenol A (BPA) is considered as being an emerging pollutant, to which both animal and human populations are continuously and inadvertently exposed. The identification of indirect biomarkers of effect could be a key factor in determining early adverse outcomes from exposure to low doses of BPA. Thus, this study on mice aims to evaluate and identify indirect biomarkers of effect through the analysis of their blood biochemistry, and of certain reproduction parameters after exposure to different BPA concentrations (0.5, 2, 4, 50, and 100 µg/kg BW/day) in drinking water over generations. Our results showed that there were no modifications in the reproductive parameters evaluated, like estrous cycle duration, litter size, or the percentage of the young alive at reaching the weaning stage, at the exposure levels evaluated. However, there were modifications in the biochemical parameters, e.g., alterations in the glucose levels, that increased significantly (p < 0.05) in the breeders at the higher exposure doses (50 and 100 µg/kg BW/day in F1; 50 µg/kg BW/day in F2 and 100 µg/kg BW/day in F3), that would suggest that the BPA could induce hyperglycemia and its complications in adult animals, probably due to some damage in the pancreas cells; albumin, that increased in the breeders exposed to the highest dose in F1 and F3, inferring possible hepatic alterations. Further, total proteins showed a diminution in their values in F1 and F2, except the group exposed to 100 µg/kg BW/day, whereas in F3 the values of this parameter increased with respect to the control group, this aspect likely being related to a possible hepatic and renal alteration. Based on these results, glucose, albumin, and total proteins could initially be considered as early indicators of indirect effect after prolonged exposure to low BPA doses over generations.

Staphylococcus aureus (S. aureus) is an important pathogen that causes clinical mastitis in goats and produces infections difficult to cure. Different antimicrobials as fluoroquinolones have been used against S. aureus. However, the studies developed to evaluate the bacterial drug interaction only have used the MIC as a single reference point with artificial growth media. The aims of this study were to describe the effect of marbofloxacin on S. aureus isolated from mastitis goats’ milk by different approaches as the minimum inhibitory and bactericidal concentrations (MIC and MBC) in cation adjusted Mueller–Hinton broth (CAMHB), serum and milk of goats at two inoculum sizes of 105 and 108 CFU/mL, the determination and analysis of the time kill curves (TKC) by non-linear mixed effect models in each growth medium and inoculum size, as well as the estimation of their pharmacokinetics/pharmacodynamics (PK/PD) cutoff values. The results obtained indicate that MIC values were higher and increases 2,4-fold in serum and 3,6-fold in milk at high inoculum, as well as the EC50 values determined by each pharmacodynamics model. Finally, the PK/PD cutoff values defined as fAUC24/MIC ratios to achieve clinical efficacy were highly dependent on inoculum and growth medium, with median values of 60–180, especially at high inoculum in milk, suggesting that further studies are necessary to evaluate and optimize the best therapeutic strategies for treating S. auerus in lactating goats.

Bisphenol-A is an emerging pollutant that is widespread in the environment, and to which live beings are continuously and inadvertently exposed. It is a substance with an endocrine-disrupting capacity, causing alterations in the reproductive, immunological, and neurological systems, among others, as well as metabolic alterations. Our study aimed to assess its clinical signs, and effects on the most relevant blood biochemical parameters, and to evaluate pituitary and gonadal histology after a chronic exposure of adult mice to different BPA doses (0.5, 2, 4, 50 and 100 µg/kg BW/day) through their drinking water. The biochemical results showed that a marked significant reduction (p < 0.05) was produced in the levels of serum glucose, hypoproteinaemia and hypoalbuminemia in the groups exposed to the highest doses, whereas in the group exposed to 50 µg/kg BW/day the glucose and total protein levels dropped, and the animals exposed to 100 µg/kg BW/day experienced a diminution in albumin levels. In the case of the group exposed to 50 µg/kg BW/day, however, hypertriglyceridemia and hypercholesterolemia were determined, and the blood parameters indicating kidney alterations such as urea and creatinine experienced a significant increase (p < 0.05) with respect to the controls. Regarding the pituitary and gonads, none of the animals exposed presented histological alterations at the doses tested, giving similar images to those of the control group. These results suggest that continuous exposure to low BPA doses could trigger an inhibition of hepatic gluconeogenesis, which would result in a hypoglycaemic state, together with an induction of the enzymes responsible for lipidic synthesis, a mechanism by which the increase in the lipid and serum cholesterol levels could be explained. Likewise, the decline in the protein and albumin levels would be indicative of a possible hepatic alteration, and the increase in urea and creatinine would point to a possible renal perturbation, derived from continuous exposure to this xenobiotic. Based on our results, it could be said that chronic exposure to low BPA doses would not produce any clinical signs or histological pituitary-gonadal effects, but it could cause modifications in some blood biochemical parameters, that could initially indicate a possible hepatic and renal effect.

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