Airway exposure to multi-walled carbon nanotubes disrupts the female reproductive cycle without affecting pregnancy outcomes in mice.

BACKGROUND: The use of multiwalled carbon nanotubes (MWCNT) is increasing due to a growing use in a variety of products across several industries. Thus, occupational exposure is also of increasing concern, particularly since airway exposure to MWCNTs can induce sustained pulmonary acute phase response and inflammation in experimental animals, which may affect female reproduction. This proof-of-principle study therefore aimed to investigate if lung exposure by intratracheal instillation of the MWCNT NM-400 would affect the estrous cycle and reproductive function in female mice. RESULTS: Estrous cycle regularity was investigated by comparing vaginal smears before and after exposure to 67 µg of NM-400, whereas reproductive function was analyzed by measuring time to delivery of litters after instillation of 2, 18 or 67 µg of NM-400. Compared to normal estrous cycling determined prior to exposure, exposure to MWCNT significantly prolonged the estrous cycle during which exposure took place, but significantly shortened the estrous cycle immediately after the exposed cycle. No consistent effects were seen on time to delivery of litter or other gestational or litter parameters, such as litter size, sex ratio, implantations and implantation loss. CONCLUSION: Lung exposure to MWCNT interfered with estrous cycling. Effects caused by MWCNTs depended on the time of exposure: the estrous stage was particularly sensitive to exposure, as animals exposed during this stage showed a higher incidence of irregular cycling after exposure. Our data indicates that MWCNT exposure may interfere with events leading to ovulation.

Genome-wide identification of mononuclear cell DNA methylation sites potentially affected by fish oil supplementation in young infants: A pilot study.

Recent evidence suggests that the effects of n-3LCPUFA might be mediated through epigenetic mechanisms, especially DNA-methylation, during pregnancy and early life. A randomized trial was conducted in 133 9-mo-old, infants who received 3.8g/day of fish oil (FO) or sunflower oil (SO) for 9 mo. In a subset of 12 children, buffy-coat DNA was extracted before and after intervention and analyzed on Illumina-Human-Methylation 450-arrays to explore genome-wide differences between the FO and SO groups. Genome-wide-methylation analysis did not reveal significant differences between groups after adjustment for multiple testing. However, analysis of the top-ranked CpG-sites revealed 43 CpG׳s that appear modified with an absolute difference in methylation of ≥10%. Methylation levels at these sites were associated with phenotypic changes mainly in blood pressure. In conclusion, our analyses suggest potential epigenome effects that might be associated with functional outcomes, yet the effect sizes were small and should be verified by additional investigation.