We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Environmentally persistent free radicals on photoaging microplastics shortens longevity via inducing oxidative stress in Caenorhabditis elegans
Summary
Researchers found that microplastics aged by sunlight develop persistent free radicals on their surface that are more toxic than fresh microplastics. In experiments with a common laboratory worm, these sun-aged microplastics caused significant oxidative stress and shortened lifespan. This is important because most microplastics in the real world have been exposed to sunlight, meaning their actual health risks may be greater than studies using brand-new plastic particles would suggest.
Microplastics (MPs) are ubiquitous environmental contaminants that exert multiple toxicological effects. Current studies have mainly focused on modeled or unaged MPs, which lack environmental relevance. The generation and toxicity of environmentally persistent free radicals (EPFRs) on photoaging polystyrene (PS) have not been well studied, and the role of EPFRs on the toxic effects of photoaged PS is easily ignored. Photoaging primarily produces EPFRs, followed by an increase in reactive oxygen species (ROS) content and oxidative potential, which alter the physicochemical properties of photoaged PS. The mean lifespan and lipofuscin content were significantly altered after acute exposure to photoaged PS for 45 d (PS-45) and 60 d (PS-60) in Caenorhabditis elegans. Intestinal ROS and gst-4::GFP expression were enhanced, concomitant with the upregulation of associated genes. Treatment with N-acetyl-l-cysteine by radical quenching test significantly decreased EPFRs levels on the aged PS and inhibited the acceleration of the aging and oxidative stress response in nematodes. Pearson's correlation analysis also indicated that the EPFRs levels were significantly associated with these factors. Thus, the EPFRs generated on photoaged PS contribute to the acceleration of aging by oxidative stress. This study provides new insights into the potential toxicity and highlights the need to consider the role of EPFRs in the toxicity assessment of photoaged PS.