Neuropathological Changes Induced by Microplastics Associated with Sachet Water in Wistar Rats: Implications for Human Neurological Health

Abstract

Background: The widespread consumption of sachet water in Nigeria has raised concerns about microplastic contamination and associated health risks, particularly after environmental exposure during storage. Although microplastics have been associated with oxidative stress and neurotoxicity, limited data exist on the neurological effects of ingestion through drinking water. Aim: This study investigated the neurotoxic effects of microplastic-contaminated sachet water in Wistar rats. Study Design: A controlled in vivo experimental study involving twenty male Wistar rats randomly assigned to five groups. Place and Duration of Study: The study was conducted in Enugu State, Nigeria. Experimental exposure lasted 30 days following a two-week acclimatisation period. Methodology: Two sachet water brands (AX and NM) were categorised into sunlight-exposed and unexposed groups. Twenty male Wistar rats were randomly assigned to five groups and orally exposed to the water samples for 30 days. Physicochemical analysis and Fourier transform infrared (FTIR) spectroscopy were performed. Brain tissues were analysed for neurotransmitters, oxidative stress markers, and histopathological changes. Data were analysed using one-way ANOVA (p < 0.05). Results: FTIR analysis revealed spectral features potentially associated with polymeric materials in the investigated water samples, including the control. Significant overall differences were observed in glutamate, glutamate decarboxylase activity, dopamine, gamma-aminobutyric acid, norepinephrine, reduced glutathione, glutathione peroxidase, malondialdehyde, and catalase. The sunlight-exposed NM group exhibited the highest mean glutamate and dopamine concentrations and the lowest mean reduced glutathione and catalase values. Histopathological examination revealed alterations including gliosis and mononuclear cell infiltration in exposed groups. Conclusions: Chronic consumption of sunlight-exposed sachet water was associated with oxidative stress, neurochemical imbalance, and structural brain changes in Wistar rats, highlighting potential neurological risks and the need for improved packaging, storage, and regulation.