In an article published on August 1, 2023, in the International Journal of Molecular Sciences, Lauren Gaspar from the University of Rhode Island, Kingston, US, and co-authors investigated the cognitive consequences of microplastics exposure in mammals.
The scientists tested the cellular uptake and effect of fluorescent polystyrene (PS) particles in the size of 0.1 and 2 µm by exposing U-2 OS cells for up to 27 hours to concentrations of 0.01 to 1000 µg/mL. Subsequently, they gave female mice (type C57BL/6J) drinking water which contained a mixture of 0.1 and 2 µm PS microplastics over the course of three weeks. They divided the mice into different exposure groups depending on their age (young = 4 months; old = 21 months) and microplastic concentration received (no microplastic; 0.0025 mg/mL; 0.025 mg/mL; 0.125 mg/mL). After the three weeks, they investigated the behavior of the mice using two tests. An open-field test for exploratory behavior and spontaneous locomotion along with a light-dark preference test for additional exploratory as well as anxiety-related behaviors. In addition, the researchers analyzed the animals’ tissue using fluorescent immunohistochemistry, Western blot, and qPCR.
Gaspar and co-authors reported that PS particles were taken up into U-2 OS cells in vitro and reduced their cell viability after 48 and 72 hours of exposure. For the mice, they recorded behavioral changes, such as an increase in the distance mice traveled. Furthermore, both the liver and the brain immune markers were significantly altered in exposed compared to control mice. Interestingly for the analyzed mice, “changes differed depending on age, indicating a possible age-dependent effect” and occurred already after that short exposure time.
The authors highlighted that many open questions on microplastic impacts on mammals remain, including the differences between animal sexes and lengths of exposure times, as well as knowledge of the method by which the microplastics are delivered.
Microplastics have been detected in human breastmilk, placenta and meconium and connected it with several health outcomes in adults and children as well as knowledge gaps on the topic.
In a review article published on August 28, 2023, in the journal Frontiers in Physiology, Yuli Geng, from Huazhong University of Science and Technology, Wuhan, China, and co-authors summarized the impacts micro- and nanoplastics can have on females during their reproductive age and offspring by looking at different species and the co-exposure with other contaminants. Topics the authors touch upon include endocrine effects, reproductive toxicity, genotoxicity, cross-generational toxicity, and combined effects with other compounds on reproductivity. One conclusion they draw is that plastic particles “tend to elicit multiple reproductive consequences in a variety of organisms, leading to the decline of female fertility and the developmental anomalies of offspring. However, it is still premature to make firm judgments regarding the toxicity on humans.” Further research, especially those using environmentally-relevant concentrations is needed.
In another review article published on August 12, 2023, in the journal Frontiers in Physiology, Yuli Geng, from Huazhong University of Science and Technology, Wuhan, China, and co-authors discussed plastic particle impacts on reproductive function of females and males. They particularly looked into impacts on germ cells and other cells of the male reproductive system, ovarian dysfunction and injury, implications for the offspring, and also evaluated the synergistic effects if the particles carry other contaminants.
Gaspar, L. et al. (2023). “Acute Exposure to Microplastics Induced Changes in Behaviorand Inflammation in Young and Old Mice.” International Journal of Molecular Sciences. DOI: 10.3390/ijms241512308
Geng, Y. et al. (2023). “Toxicity of microplastics and nanoplastics: invisible killers of female fertility and offspring health.” Frontiers in Physiology. DOI: 10.3389/fphys.2023.1254886
Hong, Y. et al. (2023). “Adverse effects of microplastics and nanoplastics on the reproductive system: A comprehensive review of fertility and potential harmful interactions.” Science of the Total Environment. DOI: 10.1016/j.scitotenv.2023.166258
Rhody Today (August 24, 2023). “Microplastics infiltrate all systems of body, cause behavioral changes.”
This article was originally published by Lisa Zimmermann at the Food Packaging Forum.