Novel insight into the mechanisms of neurotoxicity induced by glufosinate-ammonium via the microbiota-intestine-brain axis in Chinese mitten crab (Eriocheir sinensis)

Glufosinate-ammonium (GLA) is a highly water-soluble and broad-spectrum herbicide, which poses a potential risk to aquatic organisms in aquatic ecosystems. In this study, the neurotoxic effects of GLA exposure on juvenile Eriocheir sinensis were evaluated from the perspective of microbiota-intestine-brain axis. The acute toxicity test was conducted by semi-static method. The results showed that GLA exposure induced neurotoxicity in juvenile crabs, mainly manifested by significantly increased neuronal apoptosis rate, DNA damage and neuron-specific enolase activity in serum, and showed a dose-dependent manner. The expression of apoptosis-related genes showed a similar trend. Moreover, GLA exposure significantly affected the depolarization and hyperpolarization signal transduction processes in the nervous system of juvenile crabs. In addition, compared with the control group, GLA exposure resulted in significantly changed of metabolic profile in ganglia, especially amino acid metabolism and glycerophospholipid metabolism. The intestinal microbial diversity changed significantly at the phylum, family and genus levels exposed to GLA. These results revealed the potential role of microbiota-intestine-brain axis in GLA-induced neurotoxicity in juvenile crabs. Taken together, this study suggested that GLA may induce neurotoxicity damage in juvenile crabs by affecting the neurotransmitter system and nerve signal transduction, and the inapplicability of the blood-brain barrier in crustaceans may intense the effect of microbial changes on neurological function. The results of this study provide new insights into the mechanism of GLA-induced neurotoxicity and preliminarily demonstrate the toxic risk of GLA exposure to non-target aquatic species.