Salvia miltiorrhiza polysaccharides ameliorates Staphylococcus aureus-induced mastitis in rats by inhibiting activation of the NF-κB and MAPK signaling pathways

Abstract

The lactation capacity of dairy cows is critical to the productivity of the animals. Mastitis is a disease that directly affects the lactation capacity of cows. Staphylococcus aureus (S. aureus) is one of the most important pathogens that causes mastitis in dairy cows. The anti-inflammatory effect of Salvia miltiorrhiza polysaccharides (SMPs) has been demonstrated in mice and chickens. However, the effectiveness of SMPs in preventing and treating mastitis is unclear. Therefore, the purpose of this study was to explore the protective effect and mechanism of SMPs on mastitis caused by S. aureus. S. aureus was used to induce mastitis in rats, and three doses of SMPs (87.5, 175, 350 mg/kg, BW/d) were administered as treatments. The bacterial load, histopathology, and myeloperoxidase (MPO) and N-acetyl-β-D-glucosaminidase (NAGase) activities of mammary glands were observed and measured. Cytokines, including interleukin (IL)-1β, interleukin (IL)-6, and tumor necrosis factor α (TNF-α), were examined by qRT–PCR and ELISA. Key proteins in the NF-κB and MAPK signaling pathways were analyzed by Western blotting. The results showed that SMP supplementation could significantly reduce the colonization of S. aureus and the recruitment of inflammatory cells in mammary glands. S. aureus-induced gene transcription and protein expression of IL-1β, IL-6, and TNF-α were significantly suppressed in mammary glands. In addition, the increase in NF-κB and MAPK protein phosphorylation was inhibited by SMPs. These results revealed that supplementation with SMPs protected the mammary gland of rats against damage caused by S. aureus and alleviated the inflammatory response. This study provides a certain experimental basis for the treatment of S. aureus-induced mastitis with SMPs in the future.

Succinate exacerbates mastitis in mice via gut microbiota-derived extracellular vesicles

“…Mastitis, a disease that affects both humans and dairy herds, is recognized as the most common source of losses in the dairy industry. [43]. In addition to external pathogens infecting the mammary gland, an increasing number of studies in recent years have shown that the gut microbiota plays a crucial role in the pathogenesis of mastitis [40] [2].…”

The Application of Rat Models in Staphylococcus aureus Infections

“…Mastitis is an inflammatory response caused by breast tissue infections, which can be caused by a variety of bacteria [ 85 ]. And S. aureus is one of the most common pathogens of bovine infectious mastitis, as well as intramammary infections of dairy goats, which is widespread in many countries, seriously restricting the development of the global dairy industry [ 86 , 87 , 88 ].…”

“…It was found that organic selenium might regulate the inflammatory response by suppressing the activation of the NF-κB signaling pathway and attenuating the inflammatory reaction to infections by modulating the MAPK signaling pathway. Zhang et al’s study found that the anti-inflammatory effect of salvia miltiorrhizae polysaccharides (SMPs) on mastitis induced by S. aureus in rats might be related to the inhibition of the activation of NF-κB and MAPK signaling pathways and thus the inhibition of the expression of inflammatory cytokine genes [ 85 ].…”

“…However, it has been found that there are obvious differences in the immune reactivity of the mammary glands of rats and cows during mastitis caused by S. aureus [ 85 ]. Therefore, future studies should be further conducted in dairy cows.…”