Analysis of microbial diversity in mouse lungs after inhalation of nanoplastics

The study involved healthy adult male C57BL/6J mice at 8 weeks of age, divided into a solvent control group, a low-dose nanoplastic/microplastic exposure group (5 mg/kg), and a high-dose nanoplastic/microplastic exposure group (15 mg/kg). Mice in the nanoplastic/microplastic exposure groups were subjected to nasal and oral aerosol inhalation of polystyrene microspheres for 1 hour daily, continuously for 7 or 14 days; the solvent control group mice inhaled aerosolized saline using the same method. Subsequently, each group of mice was divided into two parts, with half receiving stereotactic injection of KA to establish a KA epilepsy model, while the other half underwent intraperitoneal injection of PTZ to construct a PTZ epilepsy mouse model. After modeling, the latency and mortality changes of PTZ epilepsy model mice exposed to nanoplastics/microplastics were observed; small animal in vivo imaging technology and immunofluorescence methods were employed to analyze the distribution of inhaled microplastics in the brain tissue of KA epilepsy model mice; behavioral tests and local field potential assessments were conducted to evaluate the frequency, latency, and severity of epilepsy in KA epilepsy model mice; simultaneously, brain tissue and plasma samples from KA epilepsy mice were collected to observe the morphological effects of microplastic exposure on the cerebral cortex and hippocampal tissue through H&E staining and Nissl staining; the number and distribution of astrocytes were observed using GFAP immunofluorescence; the number and distribution of microglia were assessed using CD68 and CD206 immunofluorescence; dendritic spine morphology and AMPA receptor quantity were examined using silver staining and tissue immunofluorescence; biochemical detection and ELISA methods were utilized to determine the levels of key neurotransmitters related to epilepsy and the activity of corresponding neurotransmitter metabolic enzymes in the cerebral cortex and hippocampal tissue; the expression and distribution of neurotransmitter receptors in the cortex and hippocampal tissue were detected using Western blot and immunohistochemistry; and 16s sequencing was performed to analyze the changes in the lung tissue microbiome.