Dynamics of interaction and effects of microplastics on planarian tissue regeneration and cellular homeostasis

•Planarians belonging to Dugesia japonica species were exposed to differently shaped and sized plastic microparticles via the diet.•Planarian feeding activity was not altered by the presence of microplastic mixed in food, irrespectively to the size, shape and chemistry.•The time of persistence of ingested microplastic was affected by size and shape; microplastic with a size below 6 μm were engulfed by enterocytes.•Chronic alimentary exposure to microplastics did not affect regeneration but induced apoptosis and growth delay. Increasing microplastics pollution of marine and terrestrial water is a concerning issue for ecosystems and human health. Nevertheless, the interaction of microplastics with freshwater biota is still a poorly explored field. In order to achieve information concerning the uptake, distribution and effect of microplastics in planarians, Dugesia japonica specimens have been fed with mixtures of food and differently shaped and sized plastic particles. Feeding activity and food intake were non-altered by the presence of high concentrations of different types of plastic particles. However, the persistence of microplastic within the planarian body was a function of size/shape, being small spheres (