The impact of hydrogen sulfide on gut microbiota of diabetic mice with lower limb arterial ischemia.

BACKGROUND

The prevalence of hindlimb ischemia (HLI) associated with diabetes mellitus (DM) is high. However, its prevention and treatment face significant challenges. This study explored the effects of hydrogen sulfide (H2S) intervention in mice with DM and HLI, while concurrently investigating its regulatory effects on gut microbial homeostasis.

METHODS

The diabetic model in C57BL/6J mice was established through intraperitoneal injection of streptozotocin. The HLI model was created by ligating and severing the femoral artery, with subsequent initiation of a 21-day exogenous H2S intervention. Fecal samples from the mice were collected at four time points: before model establishment, 3 days after successful induction of the diabetes model, 3 days after establishment of the HLI model, and after 21 days of H2S intervention for metagenomic analysis. Body weight, blood glucose levels, and hindlimb blood flow in the mice were monitored. Additionally, functional assessment and histopathological examination of the ischemic skeletal muscle were performed to evaluate contractile and morphological properties.

RESULTS

H2S administration significantly enhanced hindlimb blood perfusion and restored plasma H2S concentrations in diabetic mice with HLI, concurrently improving both function and morphological integrity of the ischemic skeletal muscle. Bacterial abundance at the phylum level showed changes over the course of the experiment, particularly in Bacteroidetes and Firmicutes. In the DM + HLI group, the Firmicutes-to-Bacteroidetes ratio was significantly elevated; however, H2S treatment downregulated this alteration. H2S intervention modulated the abundance of various bacterial species, increasing Lactobacillus murinus and Faecalibacterium prausnitzii, while simultaneously downregulating inflammation-related bacteria such as Ruminococcus sp. JE7A12. Microbial network analysis revealed that the DM + HLI and H2S groups had lower network complexity than the control group. Furthermore, functional metagenomic profiling identified 28 differentially expressed genes, which were annotated to 8 primary and 30 secondary KEGG pathways, with 6 genes specifically enriched in carbohydrate metabolism pathways.

CONCLUSION

Exogenous H2S administration improved hindlimb blood perfusion, restored contractile function, and preserved morphological integrity of ischemic skeletal muscle in diabetic mice with HLI. Concurrently, H2S treatment altered the abundance of gut microbiota, improving microbial balance. Targeting the gut microbiota via H₂S suggests a potential translational avenue that warrants causal investigation for the treatment of diabetic limb ischemia. Further studies are warranted to establish causal relationships and elucidate the underlying mechanisms linking H2S, gut microbiota, and vascular recovery.