中文摘要：

为研究重组人肿瘤坏死因子-α（TNF-α）对奶牛乳腺上皮细胞（BMEC）中α-平滑肌肌动蛋白（α—SMA）mRNA及蛋白表达的影响，本研究采用组织块法体外培养和纯化出BMEC。以不同浓度（0、1rig／mE、5rig／mE、10ng／mL）重组人TNF．仅作用BMEC，分别于不同时间（12b、24h、48h、72h）采用实时荧光定量RT-PCR和western blot方法检测α—SMAmRNA相对表达量及其蛋白表达。结果显示，d．SMAmRNA相对表达量12hTNF．仅处理的各组及24h，10rig／mE处理组与对照组相比差异显著（P〈0．05）；随着TNF-α浓度的升高，d．SMAmRNA的相对表达量呈升高趋势；48h和72h处理组与对照组相比差异不显著。表明TNF-α对BMEC0L．SMAmRNA的表达有一定促进作用。然而a-SMA的蛋白表达量却很低，只有24h10ng／mL处理组检测到目的蛋白的表达。研究表明，外源性TNF-α能够促进BMEC α-SMAmRNA和蛋白的表达。

英文摘要：

To explore the effect of human recombinant TNF-α on the expression of α-SMA mRNA and protein in bovine mammary epithelial cells, the in vitro cultured mammary epithelial cells were incubated with the exogenous TNF-α at 1 ng/mL, 5 ng/mL, 10 ng/mL, respectively, and the total RNA and protein were extracted from the cells in different time （12 h, 24 h, 48 h, 72 h） for examination by real-time RT-PCR with β-actin as internal reference gene and western blot. The results showed that the α-SMA mRNA levels were significantly higher （P〈0.05） in TNF-αtreatment groups （1 ng/mL, 5 ng/mL, 10 ng/mL） at 12 hours and in 10 ng/mL TNF-ct group treated at 24 hours than that in control group. Aiterwaxd, the ~t-SMA mRNA level was not remarkable between TNF-α treatment groups and control at 48 and 72 hours. However, the expression of α-SMA protein was much low and it was only detected in 10 ng/mL TNF-α treatment group at 24 hours. The results suggest that exogenous TNF-α was able to promote the expression of α-SMA mRNA and protein in bovine mammary epithelial cells.