Dog sperm DNA: Raw semen evaluation with Toluidine blue stain

Unravelling the ecotoxicological impacts of gadolinium (Gd) on Mytilus galloprovincialis embryos and sperm in seawater: A preliminary study

As the demand for rare earth elements (REEs) continues to surge in diverse industrial and medical domains, the ecological consequences of their ubiquitous presence have garnered heightened attention. Among the REEs, gadolinium (Gd), commonly used in medical imaging contrast agents, has emerged as a pivotal concern due to its inadvertent introduction into marine ecosystems via wastewater release. This study delves into the complex ecotoxicological implications of Gd contamination, focusing on its impact on the embryonic development and sperm functionality of Mytilus galloprovincialis. The findings from this study underscore the potential hazards posed by this rare element, offering a critical perspective on the ecological risks associated with Gd. Notably, this exploratory work reveals that Gd exerts a significant embryotoxic effect at elevated concentrations, with an observed half maximal effective concentration (EC50) value of 0.026 mg/L. Additionally, Gd exposure leads to a considerable reduction in sperm motility and alters sperm morfo-kinetic parameters, especially at a concentration of 5.6 mg/L. The results highlight a dose-dependent relationship between Gd exposure and the prevalence of specific malformation types in Mytilus embryos, further providing crucial insights into the potential risks imposed by this rare earth element.

Exploring the molecular and toxicological mechanism associated with interactions between heavy metals and the reproductive system of Mytilus galloprovincialis

A large number of heavy metals resulted toxic to the reproductive system, but invertebrate infertility has been poorly explored, and above all, there are limited molecular, cellular and toxicological studies. In the present work, we exposed Mytilus galloprovincialis to three individual metal chlorides (CuCl2 15 μM, CdCl2 1.5 μM, NiCl2 15 μM) and their mixture for 24 h, to evaluate the effects on the protamine-like proteins (PLs), sperm DNA and on their interaction in the formation of sperm chromatin. Under all exposure conditions, but particularly after exposure to the metals mix, relevant changes in the electrophoretic pattern, by AU-PAGE and SDS-PAGE, and in fluorescence spectroscopy measurements of PLs were shown. In addition, alterations in DNA binding of these proteins were observed by Electrophoretic Mobility Shift Assay (EMSA) and through their release from sperm nuclei. Moreover, there was evidence of increased accessibility of micrococcal nuclease to sperm chromatin, which was also confirmed by toluidine blue staining. Furthermore, morphological analyses indicated severe gonadal impairments which was also corroborated by increased PARP expression, by Western blotting, and sperm DNA fragmentation, by comet assay. Finally, we investigated the expression of stress genes, gst, hsp70 and mt10, in gonadal tissue. The latter investigations also showed that exposure to this metals mix was more harmful than exposure to the individual metals tested. The present results suggest that these metals and in particular their mixture could have a negative impact on the reproductive fitness of M. galloprovincialis. Based on these evidences, we propose a molecular mechanism.

Evaluation of DNA fragmentation in dog sperm using the sperm chromatin dispersion test

The study's objective was to adapt the Sperm Chromatin Dispersion (SCD) protocol to evaluate sperm DNA fragmentation and implement a fragmentation control in dogs. Correlation between DNA status and routine sperm parameters was also analysed. To adapt the SCD, two different mercaptoethanol (ME) concentrations were assayed (2.5 and 5%) in fourteen ejaculates from seven dogs and semen incubation with 0.3 M NaOH for 15 min at room temperature was assayed as a control for sperm DNA fragmentation. Data were analysed using a Mann-Whitney test and either Pearson's or Spearman's correlation. The selected ME concentration to use in the SCD test was 5%, as it produced the largest DNA dispersion halo while preserving the core nucleus structure. Four DNA halo patterns were identified: large dispersion halos, medium halos, small halos and nuclei without halos. Semen incubated with NaOH showed 100% sperm without halos (damaged DNA). A significant positive correlation was observed between sperm with fragmented DNA and sperm with coiled tails. Thus, it was possible to adapt the SCD protocol to evaluate dog sperm DNA fragmentation in raw semen without using a commercial kit and establish incubation with NaOH as a DNA fragmentation control. Only coiled tails showed correlation with DNA fragmentation.

The spatial and temporal distribution of cationic and anionic radicals in early embryo implantation

The main objective of this study is to obtain some knowledge of cationic and anionic radicals in early embryo implantation in mice. The method used in this study is known as histochemical staining, in which Xylidine ponceau was used at pH 2.5 and toluidine blue was used at pH 4.0. We detected the change in glycosaminoglycans and total proteins in the endometrial stroma during the preimplantation of mice. This study revealed that the distribution patterns of cationic radicals and anionic radicals are similar on days 4 and 5 of pregnancy. However, there was a distinct difference between cationic radicals and anionic radicals on day 8 of pregnancy. The distribution pattern of cationic radicals is more concentrated in the stroma near the conceptus. Laboratory studies on histochemical stain provide more information about early embryo implantation.