Potential toxicity of nanomaterials on rats/mice: a meta-analysis

Nanomaterials (NMs) are widely used in food, agriculture, electronics, and biomedicine because of unique physicochemical properties. Their ability to cross biological barriers and reach various tissues and organs raises concerns regarding their potential toxicity. Although numerous studies have investigated NMs toxicity, inconsistent findings caused by differences in NMs characteristics and experimental conditions have limited a comprehensive understanding of their overall toxicity and influencing factors. In this study, the in vivo toxicity of NMs was systematically and quantitatively evaluated through meta-analysis of serum biochemical parameters, oxidative stress, and genotoxicity indicators. The findings suggested that NMs significantly increased the levels of serum biochemical parameters related to organ function (p < 0.05). NMs also increased pro-oxidants levels (p < 0.05) and decreased antioxidants levels (p < 0.05), thereby inducing oxidative stress. Furthermore, NMs increased indicators of DNA and chromosomal damage (p < 0.05), indicating genotoxicity. Subgroup analyses indicated that the toxic effects of NMs were stronger for metal-based and smaller NMs (≤ 50 nm), and increased with longer exposure durations and higher doses, with variations also observed across exposure routes and tissues. Collectively, this meta-analysis provided quantitative evidence that NMs induced significant biochemical, oxidative, and genotoxic effects in rats and mice, with toxicological responses being influenced by NMs characteristics and exposure conditions. The findings provide valuable insights into the toxicity mechanisms and risk assessment of NMs, supporting more accurate hazard evaluation and the safe application of nanomaterials.