雷帕霉素缓解奶牛乳腺上皮细胞炎症反应的作用机制

Mastitis is a common disease in lactating dairy cows and causes huge economic losses to breeding enterprises every year. In this study, different concentrations of lipopolysaccharide (LPS) were used to induce the inflammatory response of dairy cow mammary epithelial cells. Then, 100 μg/mL LPS (LPS₁₀₀), 10 mmol/L rapamycin (RAP₁₀), and a combination of the two substances (LPS₁₀₀ + RAP₁₀) were added to the control medium (CK) respectively and the cells were treated for 24 h. After that, the cells and supernatant were collected for subsequent determination. The results showed that: without changing cell viability and apoptosis, the addition of 100 μg/mL LPS significantly increased the concentrations of interleukin - 8 (IL - 8), interleukin - 1β (IL - 1β), and tumor necrosis factor - α (TNF - α) in the supernatant (P < 0.05), but treatment with 10 mmol/L rapamycin significantly decreased the secretion of IL - 1β and TNF - α induced by LPS (P < 0.05). LPS increased the phosphorylation level of p65 protein in the nuclear factor - κB (NF - κB) pathway, but the addition of rapamycin eliminated this increase (P < 0.05). Compared with the LPS₁₀₀ group, LPS₁₀₀ + RAP₁₀ treatment decreased the phosphorylation levels of c - Jun N - terminal kinase (JNK) and p38 proteins in the mitogen - activated protein kinase (MAPK) pathway of dairy cow mammary epithelial cells (P < 0.05). In conclusion, rapamycin alleviates the inflammatory response of mammary epithelial cells caused by LPS through the NF - κB/MAPK pathway, and this result can provide a theoretical reference for the use of rapamycin in the treatment of mastitis.

乳腺炎是泌乳奶牛的常见疾病,每年给养殖企业造成巨大的经济损失。本研究采用不同浓度的脂多糖(lipopolysaccharide, LPS)诱导奶牛乳腺上皮细胞的炎症反应,之后,在对照培养基(CK)基础上分别添加100 μg/mL LPS(LPS_(100))、10 mmol/L雷帕霉素(RAP_(10))及2种物质联合添加(LPS_(100)+RAP_(10))并处理细胞24 h,结束后收集细胞及上清液用于后续测定。结果表明:在不改变细胞活力和凋亡的情况下,添加100 μg/mL LPS显著提高了上清液中白介素-8(interleukin-8, IL-8)、白介素-1β(interleukin-1β, IL-1β)和肿瘤坏死因子-α(tumor necrosis factor-α, TNF-α)的浓度(P0.05),但10 mmol/L雷帕霉素处理显著降低了LPS诱导的IL-1β和TNF-α分泌量(P<0.05)。LPS提高了核因子-κB(nuclear factor-κB, NF-κB)通路中p65蛋白的磷酸化水平,但雷帕霉素的添加消除了这种提高作用(P<0.05)。与LPS_(100)组相比, LPS_(100)+RAP_(10)处理降低了奶牛乳腺上皮细胞丝裂原活化蛋白激酶(mitogen-activated protein kinase, MAPK)通路中c-Jun N末端激酶(c-Jun N-terminal kinase, JNK)和p38蛋白的磷酸化水平(P<0.05)。综上所述,雷帕霉素通过NF- κB/MAPK通路缓解了LPS引起的乳腺上皮细胞炎症反应,该结果可为雷帕霉素用于乳腺炎的治疗提供理论参考。