Yang_2022_Ecotoxicol.Environ.Saf_249_114399

The similar nervous system structure between crustaceans and insects and the high-water solubility of thiamethoxam can lead to the more severe toxicity of thiamethoxam to crustaceans. However, the effects of thiamethoxam on crustaceans are unclear. Therefore, a 96-h acute toxicity test was performed to explore the hepatotoxicity and neurotoxicity effects of thiamethoxam on Chinese mitten crab (Eriocheir sinensis) at concentrations 0 microg/L, 150 microg/L and 300 microg/L. The antioxidant and detoxification systems (including phases I and II) were significantly activated after exposure of juvenile crabs to thiamethoxam for 24sh in 300 microg/L group, whereas the toxic activation effect in 150 microg/L group was delayed. Moreover, a similar pattern was observed for the transcription levels of immune-related genes. Further analysis of inflammatory signaling pathway-related genes showed that thiamethoxam exposure with 300 microg/L for 24sh may induce a pro-inflammatory response through the NF-kappaB pathway. In contrast, the gene expression levels in 150 microg/L group were significantly upregulated compared with 0 microg/L group after 96sh. In addition, although the acute exposure of 150 microg/L thiamethoxam did not seem to induce significant neurotoxicity, the acetylcholinesterase activity was significantly decreased in 300 microg/L group after thiamethoxam exposure for 96sh. Correspondingly, thiamethoxam exposure with 300 microg/L for 24sh resulted in significantly downregulated transcriptional levels of synaptic transmission-related genes (e.g. dopamine-, gamma-aminobutyric acid- and serotonin-related receptors). Therefore, thiamethoxam may be harmful and cause potential toxic threats such as neurotoxicity and metabolic damage to crustaceans.