Cynomorium songaricum polysaccharide attenuates high-fat diet-induced testicular dysfunction by modulating the gut microbiota.

Obesity disrupts gut microbiota homeostasis and impairs spermatogenesis; however, microbiota-targeted therapies remain insufficiently explored. In this study, a water-soluble polysaccharide(CSP1) was purified from the medicinal plant Cynomorium songaricum. Structural characterization identified CSP1 as a homogeneous α-glucan (Mw 5776 Da) with a backbone of →4)-α-D-Glcp-(1 → residues and C-6 branching. In high-fat diet (HFD)-induced obese mice, CSP1 administration alleviated testicular dysfunction by enhancing sperm count and motility, restoring serum testosterone levels, and ameliorating histopathological damage and germ cell apoptosis. Mechanistically, CSP1 remodeled the gut microbiota composition by suppressing LPS-producing taxa while enriching beneficial populations including SCFA-producing Lachnospiraceae and Bacteroidota. This reshaping reinforced intestinal barrier integrity, as evidenced by the upregulation of ZO-1, occludin, and MUC2. Consequently, CSP1 treatment led to a favorable shift in gut microbiota-derived metabolites, significantly reducing systemic LPS translocation while increasing beneficial short-chain fatty acids (SCFAs) such as acetate and propionate. These changes collectively inhibited testicular TLR4/MyD88/NF-κB activation and downstream pro-inflammatory cytokines (TNF-α, IL-1β). Fecal microbiota transplantation confirmed the causal role of the gut microbiota in mediating CSP1's protective effects. Our findings establish CSP1 as a gut-microbiota-targeting polysaccharide that alleviates obesity-associated male infertility by orchestrating a beneficial remodeling of the gut microbial ecosystem and its metabolic output, offering a novel therapeutic strategy for metabolic reproductive disorders.