Insights into the pathophysiological, molecular, and ultrastructural alterations induced by cadmium oxide nanoparticle toxicity in the midgut of Galleria mellonella

Despite the extensive applicability of cadmium oxide nanoparticles (CdO NPs) in diverse fields, there is a prominent gap in our understanding of their toxicological impacts, particularly when using invertebrate insect model organisms. This study aimed to instigate this research gap by investigating the oxidative stress and genotoxicity effects of CdO NPs using Galleria mellonella as an insect model. We evaluated the immune response, oxidative stress, stress response proteins, detoxification enzymes, DNA damage, and cell viability following exposure to a single dose of CdO NPs. A comprehensive approach was conducted, combining biochemical, molecular, ultrastructural, and morphological analyses. Interestingly, the most pronounced effect of CdO NPs on larval mortality was observed at the lowest dose of 0.01 mg/g body weight. Also, EDX analysis demonstrated a substantial accumulation of cadmium in larval midgut tissues exposed to a single injection of CdO NPs compared to the control, leading to oxidative stress, disruption of antioxidant and detoxification defense systems as well as DNA injury, and increased apoptotic and necrotic cell death lead to the destruction of the larval intestinal barrier. Moreover, pathohistological and ultrastructural investigations inspected prominent alterations and anomalies in larval midgut epithelium, including vacuolization, degeneration of cytoplasmic organelles, distorted microvilli, along with obvious necrotic signs. This study not only contributes to filling the prevailing knowledge gap concerning the toxicity of CdO NPs but also stipulates valuable insights into their broader environmental impact, potentially updating future risk assessments and monitoring decisions regarding nanomaterial applications.