Low-dose florfenicol and copper combined exposure during early life induced health risks by affecting gut microbiota and metabolome in SD rats

Effects of short-term florfenicol exposure on the gene expression pattern, midgut microbiota, and metabolome in the lepidopteran model silkworm (Bombyx mori)

Florfenicol (FF), an alternative veterinary antibiotic for chloramphenicol, has been widely utilized in livestock breeding to prevent and treat bacterial diseases. However, the toxicological effects of FF have yet to be fully disclosed. The domesticated silkworm (Bombyx mori), a lepidopteran model, was selected to assess the toxicological effects of FF dietary exposure with multi-omics. The findings showed that high-dose (250 μg/L) FF exposure increased the whole cocoon weight. High-dose FF exposure affected the species richness and community diversity of the microbiota in the silkworm midgut. Biochemical processes and innate immunity were impacted by FF exposure. The KEGG pathways impacted by the midgut microbiota and their metabolites were compared, and several pathways were found to be related to the two ecosystems. In addition, the innate immunity and lipid metabolism pathways were impacted, and some of the differentially expressed genes were enriched in these pathways. These related pathways may involve crosstalk between the midgut microbiota shift, midgut biological functions, and global gene expression. Therefore, our study also advances the application of the silkworm larval model in assessing antibiotic metabolic toxicity and provides novel insights into the potential risks of FF.

Environmental Cadmium Exposure Perturbs Gut Microbial Dysbiosis in Ducks

Ore extraction, chemical production, and agricultural fertilizers may release significant amounts of heavy metals, which may eventually accumulate widely in the environment and organisms over time, causing global ecological and health problems. As a recognized environmental contaminant, cadmium has been demonstrated to cause osteoporosis and renal injury, but research regarding the effects of cadmium on gut microbiota in ducks remains scarce. Herein, we aimed to characterize the adverse effects of cadmium on gut microbiota in ducks. Results indicated that cadmium exposure dramatically decreased gut microbial alpha diversity and caused significant changes in the main component of gut microbiota. Moreover, we also observed significant changes in the gut microbial composition in ducks exposed to cadmium. A microbial taxonomic investigation showed that Firmicutes, Bacteroidota, and Proteobacteria were the most preponderant phyla in ducks regardless of treatment, but the compositions and abundances of dominant genera were different. Meanwhile, a Metastats analysis indicated that cadmium exposure also caused a distinct increase in the levels of 1 phylum and 22 genera, as well as a significant reduction in the levels of 1 phylum and 36 genera. In summary, this investigation demonstrated that cadmium exposure could disturb gut microbial homeostasis by decreasing microbial diversity and altering microbial composition. Additionally, under the background of the rising environmental pollution caused by heavy metals, this investigation provides a crucial message for the assessment of environmental risks associated with cadmium exposure.

Co-exposure to Fe, Zn, and Cu induced neuronal ferroptosis with associated lipid metabolism disorder via the ERK/cPLA2/AA pathway

Excessive amounts of iron (Fe), zinc (Zn), and copper (Cu) can be toxic to neuronal cells, even though these are essential trace elements for animals and humans. However, the precise mechanisms underlying the neurotoxicity of exposure to mixtures of Fe, Zn, and Cu are still mostly unclear. The research aimed to investigate the influence of co-exposure to iron, zinc and copper and the related mechanisms in HT22 murine hippocampal neuronal cells. Intracellular metal content, markers of oxidative damage, and biomarkers of ferroptosis were respectively detected. Afterward, metabolomic analyses were performed to obtain a comprehensive understanding of the metal mixtures on metabolism, and the functions of key enzymes on metabolic pathways were validated. The results showed that metal co-exposure resulted in cellular iron overload and increased lipid peroxidation, accompanied by significant pathological damage and mitochondrial abnormalities in HT22 cells. Meanwhile, it was found that GSH depletion, decreased GPX4, and increased expression of the lipid metabolism gene ACSL4 play important roles in ferroptosis induced by metal mixture. Further, metabolomic analysis revealed metal co-exposure induced significant alterations in metabolite levels, especially in the glycerophospholipid metabolism pathway and the arachidonic acid metabolism pathway. The levels of cPLA2 and its metabolite, arachidonic acid, were significantly increased after metal co-exposure. Then, inhibition of cPLA2 decreased the level of arachidonic acid and attenuated ferroptosis in neuronal cells. Collectively, our findings unveiled ferroptosis induced by metal co-exposure associated with crucial molecular changes in neuronal cells, providing a novel perspective on the comprehensive toxicity risk assessment of metal mixtures.

Seaweed polysaccharide relieves hexavalent chromium-induced gut microbial homeostasis

Heavy metals released in the environment pose a huge threat to soil and water quality, food safety and public health. Additionally, humans and other mammals may also be directly exposed to heavy metals or exposed to heavy metals through the food chain, which seriously threatens the health of animals and humans. Chromium, especially hexavalent chromium [Cr (VI)], as a common heavy metal, has been shown to cause serious environmental pollution as well as intestinal damage. Thus, increasing research is devoted to finding drugs to mitigate the negative health effects of hexavalent chromium exposure. Seaweed polysaccharides have been demonstrated to have many pharmacological effects, but whether it can alleviate gut microbial dysbiosis caused by hexavalent chromium exposure has not been well characterized. Here, we hypothesized that seaweed polysaccharides could alleviate hexavalent chromium exposure-induced poor health in mice. Mice in Cr and seaweed polysaccharide treatment group was compulsively receive K2Cr2O7. At the end of the experiment, all mice were euthanized, and colon contents were collected for DNA sequencing analysis. Results showed that seaweed polysaccharide administration can restore the gut microbial dysbiosis and the reduction of gut microbial diversity caused by hexavalent chromium exposure in mice. Hexavalent chromium exposure also caused significant changes in the gut microbial composition of mice, including an increase in some pathogenic bacteria and a decrease in beneficial bacteria. However, seaweed polysaccharides administration could ameliorate the composition of gut microbiota. In conclusion, this study showed that seaweed polysaccharides can restore the negative effects of hexavalent chromium exposure in mice, including gut microbial dysbiosis. Meanwhile, this research also lays the foundation for the application of seaweed polysaccharides.