Toxicity and antimicrobial effect of silver nanoparticles in swine sperms

Photosensitive Hydrogels Encapsulating DPSCs and AgNPs for Dental Pulp Regeneration

OBJECTIVE

Pulp regeneration with bioactive dentin-pulp complex has been a research hotspot in recent years. Stem cell therapy provided an interest strategy to regenerate the dental-pulp complex. Hence, this study aimed to evaluate the effects of photosensitive gelatin methacrylate (GelMA) hydrogel encapsulating dental pulp stem cells (DPSCs) and silver nanoparticles (AgNPs) for dental pulp regeneration in vitro.

METHODS

First, the AgNPs@GelMA hydrogels were prepared by lithium phenyl-2,4,6-trimethyl-benzoyl phosphinate (LAP) initiation via blue-light emitting diode light. The physical and chemical properties of AgNPs@GelMA hydrogels were comprehensively analysed via scanning electron microscopy (SEM), and mechanical characterisation, such as swelling ability, degradation properties, and AgNP release profile. Then, AgNPs@GelMA hydrogels encapsulated DPSCs were used to establish an AgNPs@GelMA biomimetic complex, further analysing its biocompatibility, antibacterial properties, and angiogenic capacity in vitro.

RESULTS

The results indicated that GelMA hydrogels demontrated optimal characteristics with a monomer:LAP ratio of 16:1. The physico-chemical properties of AgNPs@GelMA hydrogels did not change significantly after loading with AgNPs. There was no significant difference in AgNP release rate amongst different concentrations of AgNPs@GelMA hydrogels. Fifty to 200 μg/mL AgNPs@GelMA hydrogels could disperse E faecalis biofilm and reduce its metabolic activity . Furthermore, cell proliferation was arrested in 100 and 200 μg/mL AgNPs@GelMA hydrogels. The inhibition of 50 μg/mL AgNPs@GelMA hydrogels on E faecalis biofilm was above 50%, and the cell viability of the hydrogels was higher than 90%. The angiogenesis assay indicated that AgNPs@GelMA hydrogels encapsulating DPSCs could induce the formation of capillary-like structures and express angiogenic markers CD31, vascular endothelial growth factor , and von willebrand factor (vWF) in vitro.

CONCLUSIONS

Results of this study indicate that 50 μg/mL AgNPs@GelMA hydrogels encapsulating DPSCs had significant antibacterial properties and angiogenic capacity, which could provide a significant experimental basis for the regeneration of the dentin-pulp complex.

Contaminant toxicity of concern for boars and semen used in assisted reproduction programs

The commercial swine industry utilizes artificial insemination (AI) in their breeding programs. With this assisted reproductive technology, the process starts by obtaining fresh ejaculates from desirable boars who are housed in a dedicated facility (i.e., stud) that also contains a clean-room laboratory where semen quality is assessed and then ejaculates processed into AI doses. In concert with AI adoption, disruptions in sow herd reproductive performance have been traced back to contributions made from the boar stud. Through field investigations and research, several extrinsic contaminants have been identified that impact semen quality either at the boar or AI-dose level. These contaminants can be categorized as either biological or chemical in origin, eliciting reprotoxic outcomes at the boar level and/or spermatotoxicity at the AI-dose level. Biological contaminants include multiple genera of primarily opportunistic microbes (i.e., bacteria, fungi), along with their secondary metabolites (e.g., endotoxins, exotoxins, mycotoxins). Chemical contaminants appear to originate from products used at the stud, and include cleaning agent/disinfectant residues, leachates from gloves and plastics, semen extender impurities, purified and drinking water impurities, and pesticides (i.e., biocides, fungicides, herbicides, insecticides, wood preservatives). In conclusion, contaminants are a real and constant threat to the health and productivity of a stud, and have caused significant reproductive and economic losses in the swine industry. The knowledge gained in recognizing the types and sources of contaminants provides a solid foundation for the development and implementation of pro-active strategies that mitigate risk to the industry.

An improved method to study Phytophthora cinnamomi Rands zoospores interactions with host

Phytophthora cinnamomi Rands is a highly prevalent phytopathogen worldwide, ranking among the top ten in terms of distribution. It inflicts crown rot, canker, and root rot on numerous plant species, significantly impacting the biodiversity of both flora and fauna within affected environments. With a host range spanning over 5,000 species, including important plants like Quercus suber, Quercus ilex, Castanea sativa, and commercially significant crops such as avocado (Persea americana), maize (Zea mays), and tomato (Solanum lycopersicum), Phytophthora cinnamomi poses a substantial threat to agriculture and ecosystems. The efficient dissemination of the oomycete relies on its short-lived asexually motile zoospores, which depend on water currents to infect host roots. However, managing these zoospores in the laboratory has long been challenging due to the complexity of the life cycle. Current protocols involve intricate procedures, including alternating cycles of growth, drought, and flooding. Unfortunately, these artificial conditions often result in a rapid decline in virulence, necessitating additional steps to maintain infectivity during cultivation. In our research, we sought to address this challenge by investigating zoospore survival under various conditions. Our goal was to develop a stable stock of zoospores that is both easily deployable and highly infective. Through direct freezing in liquid nitrogen, we have successfully preserved their virulence. This breakthrough eliminates the need for repeated culture transfers, simplifying the process of plant inoculation. Moreover, it enables more comprehensive studies of Phytophthora cinnamomi and its interactions with host plants.

Synthesis of green zinc-oxide nanoparticles and its dose-dependent beneficial effect on spermatozoa during preservation: sperm functional integrity, fertility and antimicrobial activity

Introduction: The development of an effective extender is important for semen preservation and the artificial insemination (AI) industry. This study demonstrates the beneficial effect of zinc oxide nanoparticles (ZnO-NPs) as an additive to semen extenders to improve semen quality, fertility, and antibacterial activity during liquid preservation in a boar model. Methods: Initially, to find out the safe concentration of ZnO-NPs in sperm cells, a wide range of ZnO-NP concentrations (0, 5, 10, 50, 100, 500, and 1,000 μM) were co-incubated with sperm at 37°C for a cytotoxic study. These NP concentrations were compared to their salt control zinc acetate (ZA) at the same concentrations and to a control group. The effect of the different concentrations of ZnO-NPs on sperm motility, membrane integrity, mitochondrial membrane potential (MMP), and apoptosis was assessed. Accordingly, the non-toxic dose was selected and supplemented in MODENA extender to determine its beneficial effect on the boar semen parameters mentioned and the lipid peroxidation (LPO) levels during liquid preservation at 16°C for 6 days. The non-cytotoxic dosage was subsequently chosen for AI, fertility investigations, and the evaluation of the antibacterial efficacy of ZnO-NPs during preservation hours. An antibacterial study of ZnO-NPs and its salt control at doses of 10 μM and 50 μM was carried out by the colony forming unit (CFU) method. Results and discussion: The cytotoxic study revealed that 5, 10, and 50 μM of ZnO-NPs are safe. Consequently, semen preserved in the MODENA extender, incorporating the non-toxic dose, exhibited 10 and 50 μM ZnO-NPs as the optimal concentrations for beneficial outcomes during liquid preservation at 16°C. ZnO-NPs of 10 μM concentration resulted in a significantly (p < 0.05) improved conception rate of 86.95% compared to the control of 73.13%. ZnO-NPs of 10 and 50 μM concentrations exhibit potent antimicrobial action by reducing the number of colonies formed with days of preservation in comparison to the negative control. The investigation concluded that the incorporation of 10 μM ZnO-NPs led to enhancements in sperm motility, membrane integrity, and MMP, attributed to a reduction in the malondialdehyde (MDA) levels. This improvement was accompanied by a concurrent increase in fertility rates, including farrowing rate and litter size, during the liquid preservation process. Furthermore, ZnO-NPs exhibited an antimicrobial effect, resulting in decreased bacterial growth while preserving boar semen at 16°C for 6 days. These findings suggest that ZnO-NPs could serve as a viable alternative to antibiotics, potentially mitigating antibiotic resistance concerns within the food chain.

Silver nanoparticle as an alternate to antibiotics in cattle semen during cryopreservation

The proposed study was to determine if the silver nanoparticles can be used as potential antimicrobial agents and can replace the use of conventional antibiotics in semen without affecting the motility and fertility of semen. The silver nanoparticles prepared by chemical reduction method were confirmed by determination of the wavelength of surface plasmon resonance peak and further characterized using Zetasizer by determining their size, polydispersity index, and zeta potential. The nanoparticles were assessed for antibacterial activity and their concentration was optimized for use in semen extender for cryopreservation. Cryopreserved semen was further evaluated for seminal parameters, antioxidant parameter, and microbial load. Prepared silver NPs showed a plasmon resonance peak at 417 nm wavelength. NPs were found to possess antibacterial activity and were supplemented in semen extender @ 125 and 250 µg/ml for semen cryopreservation. There was a significant increase in pre and post-freezing motility and other seminal parameters. The microbial load of frozen-thawed semen of control and supplemented groups were well within the permissible limits. Lipid peroxidation levels were reduced in NPs supplemented groups, and reactive oxygen species (ROS) levels were significantly reduced in semen supplemented with 125 µg/ml NPs. Thus it can be conclude that silver NPs can be successfully used as a substitute for antibiotics in cattle bull semen cryopreservation with good antimicrobial activity and no adverse effects on sperm characteristics.

Bacteria and Boar Semen Storage: Progress and Challenges

Porcine breeding today is based on artificial insemination with chilled semen. This is stored at 5 °C with antibiotic supplementation to avoid bacteriospermia. There are many negative consequences on sperm quality and functionality as a result of bacterial contamination, as well as on the health of the sow. Nowadays, various techniques are being developed to reduce the indiscriminate use of antibiotics and thus avoid the generation of antibiotic resistance genes. This review aims to inform about the bacterial contamination consequences of storing liquid semen from boar and to provide an update on current methods and alternatives to antibiotic use in cold storage.

Probing the Structure, Cytocompatibility, and Antimicrobial Efficacy of Silver-, Strontium-, and Zinc-Doped Monetite

Calcium phosphate phases are among the most widely accepted compounds for biomaterial applications, of which the resorbable phases have gained particular attention in recent years. Brushite and its anhydrous form monetite are among the most interesting resorbable calcium phosphate phases that can be applied as cements and for in situ fabrication of three-dimensional (3D) implants. Of these two dicalcium phosphate compounds, monetite is more stable and undergoes slower degradation than brushite. The purpose of the current study is to synthesize and dope monetite with the antimicrobial elements silver and zinc and the osteoinductive element strontium and investigate the possible structural variations as well as their biocompatibility and antimicrobial effectiveness. For this, powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and cryo-transmission electron microscopy (cryo-TEM) were used to thoroughly study the synthesized structures. Moreover, the ASTM E-2149-01 protocol and a cell proliferation assay were used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) and the cytocompatibility of the different phases with the Soas-2 cell line, respectively. The results confirm the successful synthesis and doping procedures, such that zinc was the most incorporated element into the monetite phase and strontium was the least incorporated element. The microbiological studies revealed that silver is a very effective antimicrobial agent at low concentrations but unsuitable at high concentrations because its cytotoxicity would prevail. On the other hand, doping the compounds with zinc led to a reasonable antimicrobial activity without compromising the biocompatibility to obviously high concentrations. The study also highlights that strontium, widely known for its osteoinductivity, bears an antimicrobial effect at high concentrations. The generated doped compounds could be beneficial for prospective studies as bone cements or for scaffold biomaterial applications.

Studies on testicular ultrastructural and hormonal changes in type-2 diabetic rats treated with highly active antiretroviral therapy conjugated silver nanoparticles

AIM

This study investigated the impact of highly active antiretroviral therapy (HAART) loaded silver nanoparticles (AgNPs) as HAART-AgNPs on the sperm count, viability, serum hormonal profile, insulin-like growth factor I (IGF-1), and testicular ultrastructure.

METHODS

Thirty-six adult male Sprague-Dawley rats were allocated into diabetic and non-diabetic groups (n = 18). The rats in the diabetic group were induced experimental type 2 diabetes using fructose and streptozotocin (frt-STZ). Animals in both groups were subdivided into three groups each, A-C and DF (n = 6), and received distilled water, HAART, and HAART-AgNP, respectively.

FINDINGS

Treatment with HAART-AgNP displayed a significant increase (p < 0.05) in serum gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testicular IGF-1 in diabetic rats. Also, electron microscopy revealed ameliorated testicular ultrastructure upon administration of HAART-AgNP in diabetic rats that were previously marked with architectural and cellular alterations. In addition, treatment with HAART-AgNP significantly reduced (p < 0.05) the blood glucose levels of diabetic rats. In contrast, the treatment of non-diabetic rats with HAART caused a significant decrease (p < 0.05) in the sperm count, serum GnRH, and testicular IGF-1, however, this treatment induced ultrastructural changes and a significant increase (p < 0.05) in serum testosterone levels in diabetic and non-diabetic rats.

SIGNIFICANCE

This study has demonstrated the beneficial impact of HAART-AgNP on the hypothalamic-pituitary-gonadal axis, IGF-1, and testicular architecture in male frt-STZ induced diabetic rats. This nanoconjugate could be a potential nano-drug candidate to cater for testicular dysfunction and metabolic derangements while managing HIV-infected male individuals.

Antimicrobially Active Semen Extenders Allow the Reduction of Antibiotic Use in Pig Insemination

Antibiotic use in semen extenders for livestock may contribute to the development and spreading of multi-drug resistance. Antimicrobial control in semen doses for artificial insemination of pigs is indispensable due to the relatively high storage temperature (17 °C). The objectives of this study were first, to examine whether the antimicrobial capacity differs between antibiotic-free extenders and second, to determine whether an antimicrobial active extender provides the possibility to reduce antibiotics. Antibiotic-free semen extenders Beltsville Thawing Solution (BTS) and Androstar Premium were inoculated at 10³ to 10⁴ CFU/mL with four pure bacterial strains isolated from boar ejaculates or a mixture thereof, and then stored for 144 h at 17 °C. Bacterial counts after aerobic culture decreased in BTS up to one log level and decreased in Androstar Premium by 2 to 3.5 log levels (p < 0.05). In semen samples from nine boars stored in the inoculated Androstar Premium extender containing half of the standard concentration of gentamicin, bacteria counts were below 10¹ CFU/mL. Likewise, half of the standard dose of apramycin and ampicillin was fully antimicrobially active and sperm quality was maintained. In conclusion, semen extenders with intrinsic antimicrobial activity allow a reduction in antibiotic use in pig insemination.

Potential toxicity of nanoparticles on the reproductive system animal models: A review

Over the past two decades, nanotechnology has been involved in an array of applications in various fields, including diagnostic kits, disease treatment, drug manufacturing, drug delivery, and gene therapy. But concerns about the toxicity of nanoparticles have greatly hindered their use; also, due to their increasing use in various industries, all members of society are exposed to the toxicity of these nanoparticles. Nanoparticles have a negative impact on various organs, including the reproductive system. They also can induce abortion in women, reduce fetal growth and development, and can damage the reproductive system and sperm morphology in men. In some cases, it has been observed that despite the modification of nanoparticles in composition, concentration, and method of administration, there is still damage to the reproductive organs. Therefore, understanding how nanoparticles affect the reproductive system is of very importance. In several studies, the nanoparticle toxicity effect on the genital organs has been investigated at the clinical and molecular levels using the in vivo and in vitro models. This study reviews these investigations and provides important data on the toxicity, hazards, and safety of nanoparticles in the reproductive system to facilitate the optimal use of nanoparticles in the industry.

Benefits and challenges of nanomaterials in assisted reproductive technologies

Assisted reproductive technology (ART) have contributed to preserve fertility in humans and to increase multiplication of genetically superior animals. Despite being highly practiced worldwide, ART presents some challenges, especially because gametes and embryos are kept in vitro for a variable period of time, and the oxidative stress in vitro can have negative impact on oocyte competence and embryo development. Nanotechnology needs to be considered to help overcome some of those impairments, since it can provide strategies to deliver antioxidants and hormones to gametes and embryos in vitro. The application of nanotechnology to ART can allow the development of new protocols using nanomaterials to improve in vitro oocyte competence and embryo production. This review discusses the applicability of nanomaterials to improve sperm selection, to deliver antioxidants and hormones to preantral follicles, oocytes, and embryos in vitro, as well as the concerns about using nanotechnology in ART.

Toxic and Microbiological Effects of Iron Oxide and Silver Nanoparticles as Additives on Extended Ram Semen

The aim of the study was to investigate the effect of iron oxide (Fe) and silver (Ag) nanoparticles (NPs) on ram semen. A skim milk extender without antibiotics was used as a diluent of 21 ejaculates (8 rams; 2-3 ejaculates/ram). The groups of control (C; semen without NPs), Fe NPs (3.072 mg Fe₃O₄/mL semen), and Ag NPs (2.048 mg Ag-Fe/mL semen) were incubated (15 °C; 30 min), and then a magnetic field was used for NPs' removal. Standard microbiological procedures were performed for all groups. Post-treated samples were stored (15 °C) for 24 h, and sperm variables (kinetics by computer assisted sperm analysis (CASA); viability; morphology; HOST; DNA integrity) were evaluated at 6 and 24 h. Semen data were analyzed by a mixed model for repeated measures and microbiological data with Student's t-test for paired samples. At 6 h of storage, VCL and rapid movement-spermatozoa, and at 24 h, total/progressive motility and amplitude of lateral head displacement (ALH) were significantly decreased in group Ag compared to control. In group Fe, progressive/rapid movement-spermatozoa were significantly lower compared to control after 24 h of storage. Only in group Ag was a significant reduction of total bacterial count revealed. In conclusion, the examined Fe NPs demonstrated slight antibacterial effect, while the examined Ag NPs provided higher antibacterial properties accompanied by cytotoxicity.

Antimicrobial activity of silver-carbon nanoparticles on the bacterial flora of bull semen

The spermicidal effects of silver nanoparticles (AgNPs) hinder its application in the field of artificial insemination. In this study, silver-carbon NPs (Ag@C NPs) was synthesized and applied as an alternative antibiotic agent for bull semen extender. Ag@C NPs were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic absorption flame spectroscopy, transmission electron microscope (TEM), and high-resolution TEM (HR-TEM). Data analysis revealed the successful synthesis of Ag@C NPs with a particle size of 1-5 nm (average particle size of 2.5 nm) embedded into carbon. The antimicrobial activity of Ag@C NPs was tested against bacteriospermia of fresh semen collected from five fertile bulls (three ejaculates/bull). Escherichia coli (E. Coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa) were isolated from fresh semen samples and identified by culture, staining, and conventional biochemical tests. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Ag@C NPs against bacteriospermia was determined at 5 and 37 °C. Ag@C NPs showed efficient antimicrobial activity (MIC: 3.125-12.5 μg/mL) against the tested strains and strong bactericidal effect on S. aureus, and P. aeruginosa (MBC: 3.125 μg/mL), with no detrimental effect (P ˃ 0.05) on the percentage of sperm motility (70.71 ± 4.82; 74.65 ± 4.46), plasma membrane integrity (68.39 ± 4.31; 72.38 ± 4.91), acrosome integrity (88.40 ± 13.21; 86.77 ± 14.23), and normal sperm morphology (86.85 ± 7.43; 87.82 ± 8.15) at concentrations of 15 and 30 μg/mL, respectively, after a cold storage of 48 h. However, Ag@C NPs showed a detrimental effect on sperm parameters in a dose dependent manner at concentrations ≥60 μg/mL. Ag@C NPs showed no adverse effect on the sperm's ultrastructure with limited sperm internalization at MIC. In conclusion, Ag@C NPs could be used as an alternative antibiotic agent for bull semen extender without a significant cytotoxic effect on the sperm during cold storage. However, further investigations for their effects on embryo production and female genitalia are still required.