Spontaneous generation of reactive oxygen species and effect on motility and fertilizability of sea urchin spermatozoa

Nanostructured cellulose sponge engineered for marine environmental remediation: Eco-safety assessment of its leachate on sea urchin reproduction (Part A)

Nanostructured cellulose sponges (CNS) have been developed as eco-friendly and sustainable engineered materials for marine environmental remediation. Despite their functionality, sensitivity, efficiency and specificity have been proved, CNS application is still limited since their environmental safety (eco-safety) has not been completely assessed. In this study, CNS were allowed to leach in natural seawater simulating the remediation process condition and the eco-safety of CNS leachate on sea urchin reproduction has been assessed by carrying out a multi-response integrated approach, combining standardized ecotoxicity tests, innovative bioassays and gamete quality assessment. Overall, the ecotoxicity data indicate that CNS leachate affects gamete quality, gamete fertilisation competence, and embryo development probably associated with the release of chemical additives used during the synthesis process. However, in the framework of the eco-design approach, consecutive leaching treatments and conditioning of CNS in seawater open the route for a new safety protocol successfully solving the ecotoxicity while maintaining CNS sorbent properties. A safe environmental application of the resulting conditioned CNS for seawater pollution remediation is envisaged.

Characterization of the effects of triclosan on sperm and embryos of Mytilus and Perna mussel species

The Greenshell™ mussel (GSM), Perna canaliculus, is a culturally and commercially important species in New Zealand. Declines in spat settlement of GSM have been observed in important growing areas and the cause(s) have not been identified. One hypothesis is that chemical contaminants could be a contributing factor. The aim to this study was to investigate the effects of acute exposure on early life stages using the anti-microbial triclosan (TCS) as a benchmark toxicant and the blue mussel (BM), Mytilus galloprovincialis, as a reference species. Sperm and embryos of BM and GSM were exposed to TCS for 1 h and 48 h, respectively. Following exposures, a range of parameters were investigated including spermatozoa cellular characteristics via flow cytometry, fertilization success, larval mortality and size. Exposure to TCS negatively impacted functional parameters of sperm, reduced the fertilization success and larval size, and increased larval mortality in both BM and GSM with LC50_48h of 94.3 and 213 µg L^-1, respectively. Triclosan increased sperm ROS production in both species, which could cause destabilisation of mitochondrial and other cellular membranes, resulting in reduced mitochondrial membrane potential (BM) and increased sperm size (GSM), leading to apoptosis in both species. Fertilization success of GSM was only affected at the highest TCS concentration tested (391 µg L^-1), but development of larvae derived from exposed sperm was affected from the lowest concentrations tested (0.5 and 5.2 µg L^-1) in both species. This highlights the importance of assessing the sensitivity of contaminants across developmental stages. Results of this study confirm that TCS causes oxidative stress and has membranotropic effects, and that early life stages of the endemic GSM are suitable to assess ecotoxicity of contaminants such as TCS.

Study on the damage of sperm induced by nickel nanoparticle exposure

As a new type of nanomaterials, nickel nanoparticles (Ni NPs) have been widely used by human beings, whose exposure probability was greatly increasing. Many studies have shown that Ni NPs can induce apoptosis, oxidative stress and DNA damage. Nowadays, male reproductive health is an important public health problem, which is a hot topic in toxicological research. In the present study, to protect reproductive health, the effect of Ni NPs exposure on spermatogenesis injury was assessed, understanding the toxicity and safety of Ni NPs. Sixty ICR male mice with 20 ± 2 g were randomly divided into five groups. The experimental groups were treated with 5 mg/kg, 15 mg/kg and 45 mg/kg Ni NPs. The reproductive toxicity of Ni NPs on male mice was evaluated by the indexes of testicular organ coefficient, testicular marker enzyme, sperm motility and histopathology. As a result, the somatic index of testis and epididymis increased in each group. Compared with the control group, the activity of testicular markers increased and the sperm motility index decreased in the low-, middle- and high-dose groups. Pathological results indicated that various cell apoptosis and disordered arrangement of cells occurred in the seminiferous tubules of the exposed groups. In conclusion, the findings of this study suggest that Ni NPs have certain damage to spermatogenesis in mice.

Assessing the impact of diclofenac, ibuprofen and sildenafil citrate (Viagra®) on the fertilisation biology of broadcast spawning marine invertebrates

Exposure to synthetic chemicals is a key environmental challenge faced by aquatic organisms. The time and dose effects of the pharmaceuticals diclofenac, ibuprofen, and sildenafil citrate on sperm motility and successful fertilisation are studied using the echinoderms, Asterias rubens and Psammechinus miliaris, and the polychaete worm Arenicola marina, all important components of the marine benthos. Motility was reduced for all species when exposed to diclofenac concentrations ≥0.1 μg/L. Exposure to ≥1.0 μg/L of ibuprofen affected only P. miliaris gametes and fertilisation success of A. marina. A. rubens and P. miliaris sperm increased in both percentage motility and swimming velocity when exposed to sildenafil citrate at concentrations ≥18 and ≥ 50 ng/L, respectively. Pre-incubation of sperm with sildenafil citrate significantly increased fertilisation success in A. rubens and P. miliaris but not in A. marina. Pre-incubated A. rubens oocytes fertilised successfully in ibuprofen. According to EU Directive 93/67/EEC, diclofenac is classified as a very toxic substance to gametes of A. rubens, P. miliaris, and A. marina (EC₅₀ = 100-1000 μg/L) while ibuprofen is classified as very toxic to gametes of P. miliaris but non-toxic to gametes of A. marina (EC₅₀ > 10,000 μg/L). The present study indicates that diclofenac exposure may have negative impacts on invertebrate reproductive success, whereas ibuprofen potentially may compromise P. miliaris reproduction. This study provides a valuable insight into the mechanisms that allow marine invertebrates to survive and reproduce in contaminated and changing habitats.