Abstract: The study of microplastic effects on biological systems is becoming increasingly important in light of the rapid rise in environmental pollution by plastic particles, which can be found in ecosystems and even in food products. Experimental studies on rodents and Danio rerio (zebrafish) have demonstrated that prolonged consumption of microplastics (particle diameter <5 mm) can disrupt intestinal barrier integrity, induce dysbiosis, cause metabolic disorders and neurotoxic effects, accumulate in various organs and tissues, and provoke a range of other pathological changes. However, such models have several limitations, including technical difficulties in working with small sample volumes, which may lead to artifacts and incorrect data extrapolation. These limitations can be overcome by using rabbits (Oryctolagus) in experimental studies. However, there are currently no data confirming the validity of the oral administration method for microparticles in this model system. Therefore, the aim of this study was to conduct a pilot experiment evaluating the effects of chronic oral administration of polystyrene latex at various doses on the biochemical and physiological parameters of rabbits (Oryctolagus cuniculus). The impact of microplastics was studied in sexually mature female Oryctolagus cuniculus rabbits. A polystyrene latex solution with a concentration of 1 mg/ml and particle diameter of 5 µm was used as the orally administered microplastic. Two different doses, 5 mg/kg and 1 mg/kg of body weight, were analyzed over an 8-day period. Biochemical blood analysis (ALT, AST, urea, creatinine, phosphorus, amylase, total calcium) was performed on the first and last day of the experiment. Throughout the study, body weight, rectal temperature, and the condition of visible mucous membranes (oral cavity and sclera) were monitored. The comparison groups consisted of the same animals before and after chronic microplastic administration. The study revealed that body weight remained stable (approximately 5.0 ± 0.6 kg, p=0.75), while rectal temperature and visual mucous membrane indicators (sclera and oral cavity) showed no significant changes and did not differ between groups (p>0.5). Only in the 5 mg/kg group was a decrease in ALT observed following prolonged particle administration (p=0.034). In the combined group (5 mg/kg and 1 mg/kg), ALT decreased by 27% by the end of the experiment (p=0.003), while serum phosphorus levels increased by 10% (p=0.027), and total calcium decreased by 4% (p=0.047) by day 8 compared to baseline values. Thus, the developed microplastic exposure model in Oryctolagus cuniculus can be considered effective, as no acute or pronounced pathological toxic effects of polystyrene microparticles were detected overall, including hepatic and renal parameters. This study was supported by the Ministry of Science and Higher Education of the Russian Federation (state contract no. 075-15-2024-629, MegaGrant).

Cite: Mikhel A.V. , Blazhenko A.A. , Kostina M.I. , Nuzhnova A.A. , Korenevsky A.V.
EVALUATION OF POLYSTYRENE MICROPARTICLES EFFECTS ON RABBITS (ORYCTOLAGUS CUNICULUS): A PILOT STUDY
THE THIRD INTERNATIONAL CONFERENCE "MICROPLASTICS IN POLYMER SCIENCE" 20-24 Oct 2025