MICROCYSTIN-LR INDUCING FERROPTOSIS IN INTESTINE OF COMMON CARP (Cyprinus
carpio ) AND INFLUENCES INTERACTIONS BETWEEN INTESTINAL MICROBIOTA AND ENVIRONMENTAL FACTORS
Previous studies provide comprehensive evidence of the environmental hazards and intestinal toxicity of microcystin -LR (MC-LR) exposure. However, the interaction between the aquacultural environment and aquatic organisms, and underlying injury mechanisms in the intestine in response to MC-LR require further clarification. In the present study, juvenile common carp (Cyprinus
carpio ) were exposed to MC-LR (0 and 10 μg /L) for 14 days. The results suggest that organic anion-transporting polypeptides 3a1, 4a1, 2b1, and 1d1 mediate MC-LR entry into intestinal tissues. Lesion morphological features (vacuolization, deformation and dilation of the endoplasmic reticulum [ER], absence of mitochondrial cristae), up-regulated mRNA expressions of ER stress, iron accumulation, and down-regulated activity of antioxidant enzymes and glutathione (GSH) content were all typical characteristics of ferroptosis in intestinal tissue following MC-LR exposure . Verrucomicrobia and
Bdellovibrionota were significantly associated with water quality (total nitrogen and total phosphorus) and GSH, and thus are suitable biomarkers of aquaculture and even natural environments in response to MC-LR exposure. These findings provide new perspectives of the ferroptosis mechanism of MC-LR-induced intestinal injury in the common carp, clarify the interactions between organisms and aquatic environments, and lay a foundation for biosafety assessment.