Human endometrial cell coculture reduces the endocrine disruptor toxicity on mouse embryo development

Bisphenol A exposure induces apoptosis and impairs early embryonic development in Xenopus laevis

Bisphenol A (BPA), an endocrine-disrupting chemical that is largely produced and used in the plastics industry, causes environmental pollution and is absorbed by humans through consumption of food and liquids in polycarbonate containers. BPA exerts developmental and genetic toxicities to embryos and offsprings, but the embryotoxicity mechanism of this chemical is unclear. This study aimed to explore the toxic effect of BPA on embryonic development and elucidate its toxicity mechanism. Embryos of Xenopus laevis as a model were treated with different concentrations (0.1, 1, 10, and 20 μM) of BPA at the two-cell stage to investigate the developmental toxicity of BPA. Embryonic development and behaviors were monitored 24 h-96 h of BPA exposure. BPA concentrations greater than 1 μM exerted significant teratogenic effects on the Xenopus embryos, which showed short tail axis, miscoiled guts, and bent notochord as the main malformations. The 20 μM BPA-treated embryos were seriously damaged in all aspects and exhibited deformity, impaired behavioral ability, and tissue damage. The DNA integrity and apoptosis of the Xenopus embryos were also investigated. Exposure to BPA concentrations higher than 0.1 μM significantly induced DNA damage (p < 0.05). The 10 and 20 μM BPA-treated embryos exhibited higher levels of cleaved caspase-3 protein than the control. The ratios of bax/bcl-2 mRNA were significantly higher in the 10 μM and 20 μM-treated embryos than the ratio in the control group. Overall, data indicated that BPA can delay the early development, induce DNA damage and apoptosis, and eventually cause multiple malformations in Xenopus embryos.

Impact of the polycarbonate strippers used in assisted reproduction techniques on embryonic development

STUDY QUESTION

Do daily manipulations of preimplantation embryos with polycarbonate (PC)-made bisphenol A (BPA)-releasing strippers influence embryo development?

SUMMARY ANSWER

Compared to glass strippers, PC strippers enhance the blastocyst development rate but this does not seem to be BPA-related.

WHAT IS KNOWN ALREADY

PC strippers have been shown to release tiny amounts (around 0.5 ng/ml BPA) of BPA in routine human IVF procedures. A chronic exposure to BPA either in vivo or in vitro during the preimplantation period can impact post-implantation and post-natal development. BPA can act rapidly by binding to membrane receptors and inducing rapid non-genomic effects.

STUDY DESIGN, SIZE, DURATION

This experimental study using mouse embryos had a balanced design and blinded evaluations of the endpoints.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In vivo fertilized zygotes were obtained from outbred Swiss CD1 mice crossings after an ovarian stimulation. The zygotes were allocated to three daily handling conditions (HCs) and cultured until Day 4 in a single human commercial medium. Each day, the embryos were handled for 20 s either in a PC stripper (HC1) or in a glass stripper (HC2). In HC3, the embryos were pre-exposed to 0.5 ng/ml BPA before being handled for 20 s in a glass stripper. Handling operations were repeated on Days 1, 2 and 3. Embryo development was assessed blindly on Day 4. Expanded blastocysts were selected for a transcriptomic analysis using Agilent Sureprint G3 Mouse GE v2 microarrays and the retrotransposon LINE1-Orf2 expression was analysed using qRT-PCR, as a proxy for a global evaluation of the epigenetic status.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to the embryos manipulated in HC2 (n = 243), those in HC1 (n = 228) developed significantly more often to the blastocyst stage (55 vs 46%; P < 0.05). It appears the effect of these PC strippers was not BPA-related because embryos pre-exposed to BPA (HC3, n = 230) showed no difference in the blastocyst rate when compared to HC2 (43 vs 46%). When analysing same-stage blastocysts, we noticed no difference in the embryo gene expression between the three HC groups.

LARGE SCALE DATA

https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE148868.

LIMITATIONS, REASONS FOR CAUTION

Our results using a mouse model designed to mimic human conditions (outbred strain, human commercial IVF dishes and a unique commercial human embryonic culture media) are reassuring since no gene was found to be differentially expressed, including LINE-1 genes, as a proxy for a global evaluation of the epigenetic status. However, no global epigenetic analysis of the genome has been performed. Furthermore, we did not evaluate post-implantation events, although BPA exposure during peri-conception could affect foeto-placental and post-natal development.

WIDER IMPLICATIONS OF THE FINDINGS

Based on the precautionary principle, several European countries banned the use of BPA in baby bottles and food packaging several years before European Agencies took an official position. The question of applying this principle to plastics in closed contact with human embryos is raised. Further studies are needed for a decision to be made.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by a grant from the Agence de Biomédecine (AOR 2016). The authors declare no competing interest.

Effects of Bisphenol-A on proliferation and expression of genes related to synthesis of polyamines, interferon tau and insulin-like growth factor 2 by ovine trophectoderm cells

This study evaluated the effects of bisphenol A (BPA) on proliferation of ovine trophectoderm (oTr1) cells, as well as expression of genes for transport of arginine and synthesis of polyamines. BPA reduced proliferation of oTr1 cells at concentrations of 1 × 10^-6, 1 × 10^-5, 1 × 10^-4 M compared to concentrations of 0, 1 × 10^-9, and 1 × 10^-8 M at 24 and 96 h of culture. Lower concentrations of BPA significantly increased expression of mRNAs for agmatinase (AGMAT), arginine decarboxylase (ADC), ornithine decarboxylase (ODC1) and solute carrier family 7 member 1 (SLC7A1). Similarly, synthesis of polyamines by oTr1 cells was greatest at lower concentrations of BPA and decreased as the dose of BPA increased. Expression of mRNAs for interferon tau (IFNT) and insulin-like growth factor 2 (IGF2) by oTr1 cells was greater than for controls at 1 × 10^-9 M BPA. Overall, the effects of BPA on proliferation and gene expression by oTr1 cells were highly dose-dependent.

Using stem cell oxygen physiology to optimize blastocyst culture while minimizing hypoxic stress

This review is a response to the Fellows Forum on testing 2% oxygen for best culture of human blastocysts (J Ass Reprod Gen 34:303-8, 1; J Ass Reprod Gen 34:309-14, 2) prior to embryo transfer. It is a general analysis in support of the position that an understanding of stem cell physiology and responses to oxygen are necessary for optimization of blastocyst culture in IVF and to enhance reproductive success in fertile women.

Bisphenol A in culture media and plastic consumables used for ART

STUDY QUESTION

Do the embryo culture media and plastic materials used during assisted reproductive technology (ART) laboratory procedures expose embryos to bisphenol A (BPA)?

SUMMARY ANSWER

BPA was not detected in embryo culture media or protein supplements at concentrations above those encountered in normal patient serum and follicular fluids.

WHAT IS KNOWN ALREADY

BPA is strongly suspected of altering the epigenome during mammalian development. Medical devices have been shown to be a source of BPA exposure in adult and neonatal intensive care units.

STUDY DESIGN, SIZE, DURATION

An analytical study of ART culture media and plastic labware products was performed under conditions close to routine practice and if BPA was detected, tests were carried out under more stringent conditions.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Two single-step embryo culture media, two sequential media and three different protein supplements [a purified human serum albumin (HSA), a synthetic serum substitute, and a recombinant HSA] were tested for BPA. Thirty-three different plastic consumables, used from oocyte collection through to embryo transfer, were tested for their ability to leach BPA into their surrounding environment.BPA concentrations were measured according to a previously described liquid chromatography/mass spectrometry method. This method is linear over the calibration range from 0.5 to 100 ng/ml using a linear model weighted by 1/X² and validated in terms of selectivity, linearity, repeatability, reproducibility and limit of quantification (0.5 ng/ml).

MAIN RESULTS AND THE ROLE OF CHANCE

Neither the culture media nor the protein supplements were shown to contain detectable levels of BPA. None of the plastic materials leached BPA into the surrounding medium at levels higher than the upper limit detected previously in serum and follicular fluids in women (about 2 ng/ml). However, the plastic of the three tested strippers used for oocyte denudation/embryo handling did contain BPA. Two of these strippers are made with polycarbonate, a plastic whose synthesis is known to require BPA.

LIMITATIONS, REASONS FOR CAUTION

This study is limited to the ART media and materials tested here and using a BPA assay with a limit of quantification at 0.5 ng/ml. A minimum volume was required for testing, and one type of plastic labware could not be tested in conditions identical to those in routine use.

WIDER IMPLICATIONS OF THE FINDINGS

Although we demonstrated that some plastic materials used in ART contain BPA, under routine conditions none appear capable of leaching BPA at levels higher than those from maternal internal exposure. However, BPA is strongly suspected of altering the epigenome. Since important epigenetic modifications occur in the early embryonic stage, it is questionable whether plastics that contain BPA, polycarbonate in particular, should be used in the manufacture of plastic consumables for ART procedures.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by a grant from the Agence de Biomédecine (AOR 2012) and by a grant from the French Ministry of Health (Clinical Research Hospital Program 2012; no.12-018-0560). The authors declared no competing interest.

Inhibitory effects of preimplantation exposure to bisphenol-A on blastocyst development and implantation

The effect of preimplantation exposure to bisphenol-A (BPA) on blastocyst development and implantation is investigated. Mice were orally administered with BPA (200, 400, 600, and 800 mg/kg/day) from Day 0.5 to Day 3.5 of their pregnancy. Blastocyst development was examined on Day 4 of pregnancy. With 400 mg/kg/day BPA, implantation site number and implantation rate significantly reduced. With 600 and 800 mg/kg/day BPA, no implantation site was observed. BPA at 800 mg/kg/day significantly reduced blastocyst development rate and hatching rate. With 400 and 600 mg/kg/day BPA, Blastocyst development rate showed no significant difference whereas hatching rate was lower. With 400, 600, and 800 mg/kg/day BPA, some embryos were detected in the fallopian tube and hatched blastocysts showed greatly increased apoptosis level and endothelial nitric oxide synthase expression. In summary, high concentration BPA delayed the transfer of embryos to the uterus, damaged blastocyst development before implantation, and inhibited embryo implantation.

Safety system for child pillion riders of underbone motorcycles in Malaysia

OBJECTIVE

Motorcycles are a common mode of transport for most Malaysians. Underbone motorcycles are one of the most common types of motorcycle used in Malaysia due to their affordable price and ease of use, especially in heavy traffic in the major cities. In Malaysia, it is common to see a young or child pillion rider clinging on to an adult at the front of the motorcycle. One of the main issues facing young pillion riders is that their safety is often not taken into account when they are riding on a motorcycle. This article reviews the legally available systems in child safety for underbone motorcycles in Malaysia while putting forth the need for a safety system for child pillion riders.

METHOD

Various databases were searched for underbone motorcycle safety systems, related legislation, motorcycle accident data, and types of injuries and these were reviewed to put forth the need for a new safety system.

RESULTS

In motorcycle-related accidents, children usually sustain lower limb injuries, which could temporarily or permanently inhibit the child's movements. Accident statistics in Malaysia, especially those involving motorcycles, reflect a pressing need for a reduction in the number of accidents. In Malaysia, the legislation does not go beyond the mandatory use of safety helmets for young pillion users. There is a pressing need for another safety system or mechanism(s) for young pillion riders of underbone motorcycles. Enforcement of laws to enforce the usage of passive safety systems such as helmets and protective gear is difficult in underdeveloped and developing countries.

CONCLUSION

The intervention of new technology is inevitable. Therefore, this article highlights the need for a new safety backrest system for child pillion riders to ensure their safety.