Abstract:The fermentation process of Platycodon grandiflorus was optimized to increase the polysaccharide yield, and the protective effect of its fermentation products on LPS-induced pneumonia-related cardiac injury was investigated. Lactobacillus plantarum xdx-6801 and Pentosaceus S. ZY-23 were combined in a 1:1 ratio. The range of fermentation parameters was screened through a single-factor experiment, and the fermentation conditions were optimized using an orthogonal experiment. Finally, the protective effect of the optimized Platycodon grandiflorus fermentation liquid (FPG) on LPS-induced acute lung injury (ALI) and cardiac damage in C57BL/6J mice was verified through in vivo experiments. The results showed that the optimal fermentation conditions were 4% inoculum, 38℃ fermentation temperature, and 60 hours of fermentation. Under these conditions, the polysaccharide concentration of FPG reached 237.48 μg·mL-1, and the total saponin concentration was 222.39 μg·mL-1, which were 2.54 times and 1.02 times higher, respectively, compared to the unfermented sample. FPG effectively alleviated lung and cardiac injury in LPS-induced ALI mice, reduced the expression of inflammatory factors IL-6 (72.30%), IL-1β (54.66%), and TNF-α (53.44%), increased the activity of antioxidant enzymes GSH (28.01%), SOD (44.35%), and T-AOC (37.81%), and reduced the accumulation of oxidative damage marker MDA (53.25%). Furthermore, FPG significantly improved the cardiac pump function of ALI mice, increasing the ejection fraction (44.50%) and fractional shortening (79.48%), and effectively reduced the level of cardiac injury marker cTnI (65.95%). In conclusion, the optimized fermentation process significantly increased the polysaccharide concentration of Platycodon grandiflorus and exhibited a marked protective effect against pneumonia-induced cardiac injury, providing a theoretical basis for the application of Platycodon grandiflorus in the prevention and treatment of pneumonia and its complications.
