Avaliação da toxicidade in vivo de microplásticos em camundongos Balb/C : estudo da exposição inalatória e seus efeitos inflamatórios

The issue of large amounts of plastic polluting the ocean and the environment is a wellknown concern in 21st-century society.In recent decades, it has led environmental management agencies to develop containment measures aimed at limiting the production and use of plastic products and increasing their recycling (The Lancet, 2017).In this context, the present thesis aims to evaluate how microplastics (MPLs) interfere with the respiratory function of animals experimentally treated with commercial MPLs.Initially, Balb/C mice were acquired directly from the central animal facility of FMUSP at the age of 2 weeks and were housed in the LIM05 animal facility for 10 days for adaptation.Two experimental groups were conducted at different times.The first group, treated in February 2023, consisted of 16 mice (males and females) exposed to microplastics via inhalation using an ultrasonic nebulizer.The second group, also consisting of 16 mice, was exposed in October 2023 and served as the control group, which inhaled saline solution using the same ultrasonic nebulizer.The animals were exposed for a period of 30 days, and both groups were euthanized after the last day of exposure.Prior to euthanasia, the animals were placed in metabolic cages for 24-hour urine collection and creatinine clearance analysis.On the day of euthanasia, they underwent respiratory mechanics analysis using the "Flexivent System," and afterward, blood was collected, and tissues were obtained through necropsy techniques in rodents.Our results suggest that inhalation exposure induces oxidative stress in the lung and kidney tissues of exposed mice.Additionally, alterations in pulmonary function are suggested, and bronchoalveolar lavage data demonstrate that exposure may modulate the immune response, increasing the presence of lymphocytes and reducing the number of macrophages.