The Protective Effects and Underlying Mechanisms of Taraxacum kok-saghyz Polysaccharides Against Intestinal Dysbiosis-Induced Mastitis Were Elucidated Using a Murine Model of the “Gut–Mammary” Axis

Abstract Background The "gut-milk axis" has emerged as a novel therapeutic approach for mastitis, involving more complex regulatory interactions than traditional mastitis. Although Dandelion polysaccharides have shown anti-mastitis potential, it remains unclear whether polysaccharides extracted from Taraxacum kok-saghyz leaves (TKP-L) can alleviate mastitis induced by intestinal microbiota dysbiosis through the gut-milk axis, and the underlying mechanisms are not fully understood. In this study, a fecal microbiota transplantation (FMT)-induced mastitis model was established to evaluate the protective effects and mechanisms of TKP-L. Pathological changes in mammary and colonic tissues, expression of pro-inflammatory cytokines, barrier-related proteins, and intestinal-to-mammary bacterial translocation using fluorescent Escherichia coli, 16S rRNA-based microbiota profiles were systematically assessed. Results TKP-L significantly alleviated mammary gland inflammation, reduced tissue redness and swelling, mitigated inflammatory cell infiltration, and restored alveolar architecture. It notably suppressed the mRNA expression of pro-inflammatory cytokines, including IL-6, IL-1β, MPO, and TNF-α. Additionally, TKP-L enhanced the expression of tight junction proteins—ZO-1, Occludin, and Claudin-3—in both intestinal and mammary tissues, which contributed to improved epithelial barrier integrity. Moreover, TKP-L effectively inhibited the translocation of intestinal bacteria to the mammary gland. Microbiota profiling revealed that TKP-L reshaped the disrupted intestinal and milk microbial communities by reducing harmful bacteria, promoting the proliferation of beneficial bacteria, and restoring overall microbial homeostasis. Conclusion Polysaccharides from the stems and leaves of TKP-L alleviate mastitis induced by intestinal flora imbalance through modulation of the gut-milk axis. The protective mechanisms involve remodelling the microbiota, enhancing the intestinal and mammary epithelial barrier integrity, and suppressing inflammatory responses. These findings provide a scientific basis for developing TKP-L as an eco-friendly strategy for the prevention and treatment of mastitis in dairy cows.