College of Traditional Chinese Veterinary Medicine, Hebei Agricultural University, 2596, Le Kai South Street, Baoding, 071001, Hebei, China.
Hebei Provincial Veterinary Biotechnology Innovation Center, Baoding, China.
BMC Vet Res. 2022 May 27;18(1):201. doi: 10.1186/s12917-022-03312-6.
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.
奶牛的泌乳能力对动物的生产力至关重要。乳腺炎是一种直接影响奶牛泌乳能力的疾病。金黄色葡萄球菌（S. aureus）是引起奶牛乳腺炎的最重要病原体之一。丹参多糖（SMPs）在小鼠和鸡中的抗炎作用已得到证实。然而，SMPs 预防和治疗乳腺炎的效果尚不清楚。因此，本研究旨在探讨 SMPs 对金黄色葡萄球菌引起的乳腺炎的保护作用及其机制。用金黄色葡萄球菌诱导大鼠乳腺炎，并给予 SMPs（87.5、175、350mg/kg，BW/d）三个剂量进行治疗。观察和测量乳腺的细菌负荷、组织病理学、髓过氧化物酶（MPO）和 N-乙酰-β-D-氨基葡萄糖苷酶（NAGase）活性。通过 qRT-PCR 和 ELISA 检测细胞因子，包括白细胞介素（IL）-1β、白细胞介素（IL）-6 和肿瘤坏死因子 α（TNF-α）。通过 Western blot 分析 NF-κB 和 MAPK 信号通路中的关键蛋白。结果表明，SMP 补充可显著降低金黄色葡萄球菌在乳腺中的定植和炎症细胞的募集。金黄色葡萄球菌诱导的乳腺中 IL-1β、IL-6 和 TNF-α 的基因转录和蛋白表达明显受到抑制。此外，SMPs 抑制了 NF-κB 和 MAPK 蛋白磷酸化的增加。这些结果表明，SMPs 补充可保护大鼠乳腺免受金黄色葡萄球菌的损伤，并减轻炎症反应。本研究为今后用 SMPs 治疗金黄色葡萄球菌引起的乳腺炎提供了一定的实验依据。
