Gut microbiota depletion amplifies heat-induced neurotoxicity via a hemolymph-mediated gut-neural axis in the Chinese mitten crab

Using the Chinese mitten crab as a model, we established a physiologically relevant framework combining heat stress with antibiotic-induced microbiota depletion to elucidate the critical role of the microbiota-gut-neural axis in modulating heat-induced neurotoxicity. Results showed that antibiotic treatment significantly reshaped the gut microbiome and compromised intestinal barrier function. Under microbiota-depleted conditions, heat stress triggered a synergistic amplification of neurotoxicity, characterized by disrupted neurotransmitter homeostasis, synchronous cross-tissue alterations in receptor gene expression, and intensified neural DNA damage. Metabolomic analysis revealed the abnormal accumulation of neuroactive metabolites, specifically DON and Urea-Glu, which were strongly correlated with gut barrier disruption. These findings suggest that circulating metabolites mediate the neurotoxic effects of dysbiosis via the hemolymph. This study confirms the functional existence of the microbiota-gut-neural axis and identifies hemolymph metabolites as key mediators linking gut homeostasis to neural stress responses, providing new insights into the physiological resilience of ectotherms under climate warming.