Mastitis in dairy cows, typically caused by bacterial infection, is a common inflammatory condition of the mammary tissue that leads to fibrosis, adversely affecting cow health, milk production, and dairy product quality. Astragalus polysaccharide (APS) has shown effectiveness in alleviating inflammation and fibrosis in various organs. The study employed lipopolysaccharide (LPS) to induce fibrotic conditions in two experimental systems: MAC-T bovine mammary epithelial cells and Kunming mouse models. Key parameters, including relative gene mRNA expression, protein levels, and reactive oxygen species (ROS) levels, were assessed using RT-qPCR, Western blotting (WB), and 2’,7’-Dichlorofluorescin diacetate (DCFH-DA) techniques, while histological analysis of mammary tissue was performed using H&E and Masson trichrome staining. Measuring malondialdehyde (MDA) levels, assessing the enzyme activities of catalase (CAT), and superoxide dismutase (SOD) were two methods of assessing oxidative stress. These methods were also tested in mouse mammary glands. APS significantly decreased ROS concentrations (p < 0.01), restored oxidative stress balance in mice (p < 0.05), and reduced fibrosis and inflammation, as demonstrated by histological observations and analysis. It also exerted regulatory effects on fibrosis markers (E-cadherin, N-cadherin, α-SMA) and inflammation markers (NLRP3, ASC, Caspase-1, IL-1β), as demonstrated by changes in their mRNA and protein expression. These findings endorse APS’s viability as an alternative therapeutic agent for mammary fibrosis therapy by demonstrating its ability to inhibit epithelial-mesenchymal transition (EMT) in vitro and mammary fibrosis in vivo, while also mitigating ROS production and reducing inflammation.

Cow mastitis is a major challenge in dairy farming, significantly affecting both milk quality and cow health. Cytochalasin B (CB) is a fungal toxin and an actin cytoskeleton depolymerizing agent that exhibits anti-inflammatory and antitumor properties; however, its mechanism in cow mastitis remains unclear. In this study, we systematically evaluated the effects of CB on mastitis using an LPS-induced inflammation model in bovine mammary epithelial cells (MAC-T) and a mouse mastitis model. The techniques employed included Real-time quantitative PCR detecting system (qPCR), Western blot, HE staining, immunofluorescence (IF), and immunohistochemistry (IHC). The results demonstrated that CB significantly alleviated LPS-induced mastitis by downregulating the expression of pro-inflammatory factors IL-1β, TNF-α, and the NLRP3 inflammasome while also reducing cell apoptosis. Further mechanistic investigations revealed that CB mitigates the inflammatory response by inhibiting the expression of ARPC3, ARPC4, and HSP70, thereby disrupting cytoskeletal rearrangement and the activation of the NLRP3 inflammasome. Overall, this study reveals the potential therapeutic role of CB in cow mastitis and provides a theoretical foundation for developing novel intervention strategies.

Mastitis in dairy cows, typically caused by bacterial infection, is a common inflammatory condition of the mammary tissue that leads to fibrosis, adversely affecting cow health, milk production, and dairy product quality. Astragalus polysaccharide (APS) has shown effectiveness in alleviating inflammation and fibrosis in various organs. In this study, a lipopolysaccharide (LPS)-induced fibrosis model was established using a bovine mammary epithelial cell line (MAC-T) and Kunming rats. Key parameters, including relative gene mRNA expression, protein levels, and reactive oxygen species (ROS) content, were assessed using RT-qPCR, Western blotting (WB), and DCFH-DA techniques, while histological analysis of breast tissue was performed using H&E and Masson trichrome staining. Oxidative stress markers, such as malondialdehyde (MDA) concentration and enzymatic activities of superoxide dismutase (SOD) and catalase (CAT), were also evaluated in mouse mammary glands. APS treatment modulated fibrosis markers (E-cadherin, N-cadherin, and α-SMA) and inflammation markers (NLRP3, ASC, Caspase-1, and IL-1β) at both mRNA and protein levels, significantly reduced ROS concentrations (P<0.01), restored oxidative stress balance in mice (P<0.05), and mitigated fibrosis and inflammation, as revealed by histological observations. These findings demonstrate that APS can mitigate ROS accumulation, reduce inflammation, and inhibit epithelial-mesenchymal transition (EMT) in vitro and mammary fibrosis in vivo, supporting its potential as an alternative therapeutic agent for mammary fibrosis treatment.