The Uptake and Distribution Evidence of Nano-and Microplastics in vivo after a Single High Dose of Oral Exposure

Objective Tissue uptake and distribution of nano-/microplastics was studied at a single high dose by gavage in vivo.Methods Fluorescent microspheres(100 nm,3μm,and 10μm)were given once at a dose of 200 mg/(kg∙body weight).The fluorescence intensity(FI)in observed organs was measured using the IVIS Spectrum at 0.5,1,2,and 4 h after administration.Histopathology was performed to corroborate these findings.Results In the 100 nm group,the FI of the stomach and small intestine were highest at 0.5 h,and the FI of the large intestine,excrement,lung,kidney,liver,and skeletal muscles were highest at 4 h compared with the control group(P<0.05).In the 3μm group,the FI only increased in the lung at 2 h(P<0.05).In the 10μm group,the FI increased in the large intestine and excrement at 2 h,and in the kidney at 4 h(P<0.05).The presence of nano-/microplastics in tissues was further verified by histopathology.The peak time of nanoplastic absorption in blood was confirmed.Conclusion Nanoplastics translocated rapidly to observed organs/tissues through blood circulation;however,only small amounts of MPs could penetrate the organs.

Evidence on Invasion of Blood,Adipose Tissues,Nervous System and Reproductive System of Mice After a Single Oral Exposure:Nanoplastics versus Microplastics

Objective This study was designed to provide the evidences on the toxicokinetics of microplastics(MPs)and nanoplastics(NPs)in the bodies of mammals.Methods 100 nm,3μm,and 10μm fluorescent polystyrene(PS)beads were administered to mice once by gavage at a dose of 200 mg/kg body weight.The levels and change of fluorescence intensity in samples of blood,subcutaneous fat,perirenal fat,peritesticular fat,cerebrum,cerebellum,testis,and epididymis were measured at 0.5,1,2,and 4 h after administration using an IVIS Spectrum small-animal imaging system.Histological examination,confocal laser scanning,and transmission electron microscope were performed to corroborate the findings.Results After confirming fluorescent dye leaching and impact of pH value,increased levels of fluorescence intensity in blood,all adipose tissues examined,cerebrum,cerebellum,and testis were measured in the 100 nm group,but not in the 3 and 10μm groups except in the cerebellum and testis at 4 h for the 3μm PS beads.The presence of PS beads was further corroborated.Conclusion After a single oral exposure,NPs are absorbed rapidly in the blood,accumulate in adipose tissues,and penetrate the blood-brain/testis barriers.As expected,the toxicokinetics of MPs is significantly size-dependent in mammals.