灵芝菌丝体多糖的理化性质及对D-半乳糖诱导衰老小鼠肠道菌群的调节作用OA

This study aimed to characterize the physicochemical properties of the polysaccharide extracted from the mycelium of Ganoderma lingzhi(SGP)and to elucidate its anti-aging effects along with its modulatory impact on intestinal microbiota.The compositional and structural properties of SGP were analyzed using high-performance anion exchange chromatography,gel permeation chromatography coupled with refractive index and multi-angle laser light scattering detectors,and Fourier transform infrared spectroscopy.An aging model was established in mice via D-galactose induction.Subsequently,antioxidant enzyme activities,total antioxidant capacity,and levels of oxidative products were measured in serum,liver,and whole brain tissues across experimental groups.Histopathological examination of liver tissues was also conducted.Quantitative real-time PCR was employed to assess hepatic mRNA expression levels of reactive oxygen species(ROS),nuclear factor erythroid 2-related factor 2(Nrf2),and Kelch-like ECH-associated protein 1(Keap1).Additionally,alterations in the intestinal microbiota were evaluated through 16S rDNA sequencing analysis.Results indicated that SGP predominantly comprised arabinose,galactose,glucose,mannose,and fructose,with an average molecular weight of 4.943 7 × 104 Da.Administration of SGP enhanced antioxidant enzyme activities and total antioxidant capacity while reducing oxidative product concentrations,thereby mitigating aging-associated organ damage.Molecular analyses suggested that SGP exerts its anti-aging effects by activating the Nrf2/Keap1 signaling pathway and suppressing ROS accumulation.Furthermore,SGP treatment increased microbial diversity and species richness in aged mice,notably elevating the relative abundance of Bacteroidota and Faecalibaculum,while decreasing Firmicutes abundance.Collectively,these findings demonstrate that SGP possesses potent in vitro antioxidant properties and ameliorates oxidative stress in aging mice via modulation of the Nrf2/Keap1 pathway;it also contributes to the restoration of intestinal microbial homeostasis,thereby exerting anti-aging effects.