Oligomeric proanthocyanidins (OPCs), classified as condensed tannins, have significant effects in anti-oxidation, anti-inflammation and anti-cancer. This study was performed to investigate anti-inflammatory effects of OPCs and the mechanism underlying these effects in lipopolysaccharide (LPS)-stimulated bovine mammary epithelial cells (MAC-T). Real-time PCR and ELISA assays indicated that OPCs treatment at 1, 3 and 5 μg/mL significantly reduced mRNA and protein respectively of oxidant indicators cyclooxygenase-2 (COX-2) (P<0.05) and inducible nitric oxide synthase (iNOS) (P<0.01) as well as inflammation cytokines interleukin (IL)-6 (P<0.01), IL-1β (P<0.01) and tumor necrosis factor-α (TNF-α) (P<0.05) in LPS-induced MAC-T cells. Moreover, OPCs down-regulated LPS-induced phosphorylation of p65 and inhibitor of nuclear factor kappa B (NF-κB) (IκB) in the NF-κB signaling pathway (P < 0.01), and they inhibited p65 translocation from the cytoplasm to the nucleus as revealed by immunofluorescence test and western blot. Additionally, OPCs decreased phosphorylation of p38, extracellular signal regulated kinase and c-jun NH₂-terminal kinase in the MAPK signaling pathway (P < 0.01). In conclusion, the anti-inflammatory and antioxidant activities of OPCs involve NF-κB and MAPK signaling pathways, thus inhibiting expression of pro-inflammatory factors and oxidation indicators. These findings provide novel experimental evidence for the further practical application of OPCs in prevention and treatment of bovine mastitis.

中文翻译：

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通过抑制 LPS 刺激的 MAC-T 细胞中的 NF-κB 和 MAPK，寡聚原花青素的抗炎活性。

低聚原花青素 (OPCs) 归类为缩合单宁，具有显着的抗氧化、抗炎和抗癌作用。本研究旨在研究原花青素的抗炎作用以及这些作用在脂多糖 (LPS) 刺激的牛乳腺上皮细胞 (MAC-T) 中的潜在机制。实时 PCR 和 ELISA 检测表明，1、3 和 5 μg/mL 的 OPCs 分别显着降低了氧化指标环氧合酶 2 (COX-2) ( P <0.05) 和诱导型一氧化氮合酶 (iNOS)的 mRNA 和蛋白质( P <0.01) 以及炎症细胞因子白细胞介素 (IL)-6 ( P <0.01)、IL-1β ( P <0.01) 和肿瘤坏死因子-α (TNF-α) ( P<0.05) 在 LPS 诱导的 MAC-T 细胞中。此外，OPCs 下调 LPS 诱导的 p65 磷酸化和 NF-κB 信号通路中核因子 kappa B (NF-κB) (IκB) 的抑制因子 ( P < 0.01)，并抑制 p65 从细胞质向细胞质转移。免疫荧光测试和蛋白质印迹显示的细胞核。此外，OPC 降低了 MAPK 信号通路中 p38、细胞外信号调节激酶和 c-jun NH _{2末端激酶的磷酸化 (} P< 0.01)。总之，OPCs 的抗炎和抗氧化活性涉及 NF-κB 和 MAPK 信号通路，从而抑制促炎因子和氧化指标的表达。这些发现为原花青素在牛乳腺炎防治中的进一步实际应用提供了新的实验证据。