研究苜蓿黄酮对脂多糖(LPS)诱导下奶牛乳腺上皮细胞凋亡的影响.将奶牛乳腺上皮细胞分成4个组,即基础培养基、基础培养基中加入1 μg·mL-1的LPS、基础培养基中加入1 μg·mL-1的LPS和75 μg·mL-1苜蓿黄酮、基础培养基中加入75 μg·mL-1苜蓿黄酮.细胞在37℃,5％ CO2的培养箱中培养.结果表明:1)LPS刺激12 h后奶牛乳腺上皮细胞活性下降,而添加苜蓿黄酮能够极显著抑制LPS诱导下细胞活性的下降(P＜0.01).2)在LPS刺激下,细胞内的活性氧(ROS)浓度升高,而添加苜蓿黄酮能够显著降低其浓度(P＜0.05).3)LPS显著上调细胞的IL-1β、IL-6、TNF-a、TLR2、TLR4和MyD88表达(P＜0.01),而苜蓿黄酮能够显著下调细胞的IL-1β、IL-6、TNF-α和TLR 2表达(P＜0.01或P＜0.05).4)在LPS刺激下,p53、Caspase3、p38和P-p38蛋白的表达显著升高(P＜0.01或P＜0.05),而添加苜蓿黄酮能够显著降低p53和p38蛋白的表达(P＜0.05).在LPS诱导下,苜蓿黄酮能够通过降低ROS浓度,抑制细胞凋亡,提高细胞活性;可能通过抑制TLR2/MyD88信号通路来降低细胞炎症因子的表达,从而保护细胞免受炎性损伤.%The aim of this study was to examine the effect of alfalfa flavonoids (AF) on apoptosis of bovine mammary epithelial cells (BMECs) induced by lipopolysaccharide (LPS).The BMECs were exposed to 4 treatments;medium containing 0 μg · mL 1 LPS and AF (control),1 μg · mL-1 LPS (L),1 μg · mL-1 LPS and 75 μg · mL-1 AF(L+F),and 75 μg · mL-1 AF(F),respectively.The BMECs were cultured in cell incubator at 37 ℃,5％ CO2.The results were as follow:1) AF supplementation significantly reduced the viability of BMECs stimulated by LPS for 12 h (P＜0.01).2) LPS significantly increased the concentration of ROS in cells (P＜0.01),whereas AF supplementation significantly reduced the concentration of ROS in cells induced by LPS (P＜0.05).3) LPS significantly increased the relative expression of IL-1β,IL-6,TNF-α,TLR2,TLR4 and MyD88 in cells (P＜0.01),but the relative expression of IL-1β,IL-6,TNF-a and TLR2 in cells induced by LPS was significantly reduce by AF supplementation (P＜0.01 or P＜0.05).4) LPS significantly increased the expression of p53,Caspase3,p38 and P-p38 proteins in cells (P＜0.01 or P＜0.05),whereas AF supplementation inhibited the expression of p53 and p38 proteins in cells induced by LPS (P＜0.05).The results showed that AF could improve the viability of cells and inhibit apoptosis by reducing the concentration of ROS and that AF might play a role in protecting cells against inflammatory injure by inhibiting the TLR2/MyD88 signaling pathway.
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