Neurotoxicity, behavioral changes and gene-expression profile of mice exposed to SnS₂ nanoflowers

Recently, interest in the potential applications of tin disulphide nanoflowers (SnS₂ NFs) in the treatment of waste water and their antibacterial properties has increased. However, their effects on neurotoxicity, brain cognition and behavioural injury, as well as the underlying mechanisms of these effects have remained unknown. In the present study, we compared the neurotoxicity of SnS₂ NFs (50 nm) administered intragastrically at different doses (5, 10, and 50 mg kg^-1) in mice for 60 days. The results showed that the neurotoxicity of SnS₂ NFs in mice is dose-dependent. Furthermore, expression levels of genes related to oxidative stress, metabolism and signal transduction were also modified in the brain tissues of mice exposed to SnS₂ NFs, supporting the SnS₂ NF-dependent neurotoxic phenotype. Additionally, SnS₂ NF exposure resulted in an abnormal ultrastructure in the hippocampus of the treated mice. Nevertheless, their body weight, organ coefficient and behaviour assessed in an open-field test and learning and memory test results assessed using a Morris water maze test remained unaffected. This suggested that the increased risk of neurotoxicity in SnS₂ NF-treated mice was dependent on the dosage of SnS₂ NFs. The relative level of safety was <5 mg kg^-1 for 50 nm SnS₂ NFs. The present study provides an experimental basis for the safe application of SnS₂ NFs; however, chronic behavioural effects of SnS₂ NFs remain unknown.