No abstract

Studies have indicated that the ethanol exposure impairs the gut microbiota, At the same time, high levels of alcohol exposure damage sperm in mice. However, whether the gut microbiota is involved in mediating the effects of alcohol on sperm quality remains unclear. This study aimed to assess the effect of chronic alcohol consumption on intestinal microbiota in mice and analyze the potential pathophysiological effect of altered intestinal microbiota on sperm quality. We established a mouse model of chronic alcohol consumption by allowing male C57 mice to freely ingest 10% ethanol for 10 weeks, and collected the fecal microbiota of the male mice in the chronic drinking group (alcohol) and the control group (control) and transplanted the specimens into the transplant groups (the alcohol-fecal microbiota transplantation [FMT] group and the control-FMT group). Sperm quality was significantly decreased in the alcohol-FMT group compared with the control-FMT group. Gut microbiota analysis revealed that the abundance of 11 operational taxonomic units (OTUs) was altered in the alcohol-FMT group. Nontargeted metabolomics identified 105 differentially altered metabolites, which were mainly annotated to amino acids, lipids, glycerophosphoethanolamine, organic oxygenic compounds, organic acids and their derivatives, steroids, and flavonoids. In particular, the oxidative phosphorylation pathway, which is the key to spermatogenesis, was significantly enriched in the alcohol-FMT group. Moreover, compared with the control-FMT group, the alcohol-FMT group presented significantly higher serum endotoxin and inflammatory cytokine levels, with more pronounced T cell and macrophage infiltration in the intestinal lamina propria and elevated levels of testicular inflammatory cytokines. In addition, RNA sequencing showed significant differences in the expression of testis-related genes between the alcohol-FMT group and the control-FMT group. In particular, the expression of genes involved in gamete meiosis, testicular mitochondrial function, and the cell division cycle was significantly reduced in alcohol-FMT mice. In conclusion, these findings indicated that intestinal dysbiosis induced by chronic alcohol consumption may be an important factor contributing to impaired sperm quality. Chronic alcohol consumption induces intestinal dysbiosis, which then leads to metabolic disorders, elevated serum endotoxin and inflammatory cytokine levels, testicular inflammation, abnormal expression of related genes, and ultimately, impaired sperm quality. These findings are potentially useful for the treatment of male infertility.

Owing to the localized surface plasmon resonance (LSPR), dynamic manipulation of optical properties through the structure evolution of plasmonic nanoparticles has been intensively studied for practical applications. This paper describes a novel method for direct reversible self-assembly and dis-assembly of Au nanoparticles (AuNPs) in water driven by pH stimuli. Using 3-aminopropyltriethoxysilane (APTES) as the capping ligand and pH-responsive agent, the APTES hydrolyzes rapidly in response to acid and then condenses into silicon. On the contrary, the condensed silicon can be broken down into silicate by base, which subsequently deprotonates the APTES on AuNPs. By controlling condensation and decomposition of APTES, the plasmonic coupling among adjacent AuNPs could be reversible tuned to display the plasmonic color switching. This study provides a facile and distinctive strategy to regulate the reversible self-assembly of AuNPs, and it also offers a new avenue for other plasmonic nanoparticles to adjust plasmonic properties via reversible self-assembly.