We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Microplastic cytotoxicity and the phagocytic response of earthworm immune cells
Summary
Researchers tested the effects of polyethylene microplastics on earthworm immune cells in laboratory conditions and found that cells engulfed 85% of small particles (1-10 micrometers) but showed negligible uptake of larger ones (20-27 micrometers). Both particle sizes caused dramatic drops in cell viability to just 6-7%, compared to 94% in untreated controls. The findings reveal that different microplastic sizes trigger distinct pathways of cellular damage in soil organisms.
Agricultural soil is a major sink for microplastics, which accumulate as a consequence of plastic mulching, wastewater irrigation, and the application of organic materials containing plastic residues as soil amendments. Soil organisms like earthworms are sensitive to microplastic exposure. However, a global regulatory gap currently exists regarding small plastic fragments (< 2 mm) in agricultural soils, and there is limited information on the influence of size-dependent microplastics on the direct cellular immune responses of earthworms, particularly under in vitro conditions. In this paper, we conducted an in vitro investigation of the cytotoxicity of polyethylene microplastics in Eisenia fetida coelomocytes, which revealed size-dependent differences in phagocytosis. Coelomocytes engulfed 85% of small polyethylene microplastics (1-10 µm) through phagocytosis, but there was negligible phagocytosis of larger polyethylene microplastics (20-27 µm). Cell viability was 6-7% when coelomocytes were exposed to 1-10 µm and 20-27 µm-sized microplastics, significantly less than the 94% viability of coelomocytes in the untreated control. This finding highlights distinct cytotoxic pathways triggered by different microplastic size: small microplastics (1-10 µm) accumulating in cells, whereas larger microplastics (20-27 µm in this study) appear to cause frustrated phagocytosis, causing inflammation or cellular damage or death.
Sign in to start a discussion.
More Papers Like This
Ecotoxicological effects of different size ranges of industrial-grade polyethylene and polypropylene microplastics on earthworms Eisenia fetida
Researchers exposed earthworms to industrial-grade polyethylene and polypropylene microplastics of various sizes and found that the worms ingested all types of particles tested. The microplastics caused oxidative stress and DNA damage in the earthworms, with the severity depending on both the size and type of plastic. Gene analysis revealed that exposure disrupted pathways related to nervous system function, oxidative stress, and inflammation, indicating that microplastics pose ecological risks to important soil organisms.
Effects of polyethylene microplastics stress on soil physicochemical properties mediated by earthworm Eisenia fetida
Researchers exposed earthworms to polyethylene microplastics of two sizes and found that smaller particles (13 micrometers) were more toxic than larger ones (130 micrometers), reducing survival and growth more severely. The microplastics caused oxidative stress in the worms and altered key soil properties including pH and organic carbon content. Since earthworms play a vital role in maintaining healthy soil for agriculture, this damage could affect soil quality and ultimately the food grown in microplastic-contaminated farmland.
Microplastic pollution inhibits the phagocytosis of E. coli by earthworm immune cells in soil
Researchers discovered that polystyrene microplastics inhibit the ability of earthworm immune cells to engulf bacteria through phagocytosis, both in laboratory tests and in soil experiments. The microplastics also caused mitochondrial damage in intestinal tissue and suppressed oxidative stress responses in immune cells. This is the first study to demonstrate that microplastic pollution in soil can compromise the immune defenses of earthworms, key organisms in soil ecosystem health.
Microplastic-induced reductions in population abundance and body size of soil nematodes
Researchers exposed three species of soil nematodes to polystyrene microplastics of different sizes and found significant reductions in both population numbers and body size after 45 days. The smallest particles (0.1 micrometers) caused the most severe effects, demonstrating that microplastic toxicity to soil organisms is size-dependent.
Visualizing and assessing the size-dependent oral uptake, tissue distribution, and detrimental effect of polystyrene microplastics in Eisenia fetida
Researchers investigated size-dependent effects of polystyrene microplastics on earthworms (Eisenia fetida) using particles of 70 nanometers, 1 micrometer, and 10 micrometers at various doses. They found that smaller particles were more readily taken up into tissues and caused greater oxidative stress and tissue damage. The study suggests that nanoscale plastic particles may pose higher ecological risks to soil organisms than larger microplastics due to their enhanced ability to penetrate biological barriers.