The aim of this study was to examine the lipopolysaccharide (LPS)-induced effects of tricin on inflammatory and lacto-protein gene expression in bovine mammary epithelial cells (BMECs).The BMECs were divided into four treatment groups.The BMECs were cultured in the medium without LPS(L) and tricin(T).The BMECs in groups L and L+T were treated with 1 μg · mL-1 of LPS without tricin,or with 10 μg · mL-1 of tricin,respectively.The BMECs in group T were cultured in the medium with 10 μg · mL-1 tricin.The results showed that the viability of cells was reduced significantly in the L treatment group (P＜0.05),whereas cell viability was increased significantly in the T treatment group (P＜0.01).The activity of superoxide dismutase(SOD) in the T treatment group was significantly higher than that of the L treatment group (P＜0.01),but the contents of NO and malondialdehyde(MDA) showed the opposite results.The relative expression of IL-1β,IL 6,TNF-α,TLR2,TLR4,and MyD88 was elevated by LPS (P＜0.01),whereas tricin supplementation reduced the relative expression of IL-1β,TNF-a,TLR2,and TLR4 in cells induced by LPS (P＜0.01).The relative expression of JAK2,STAT5,mTOR,4EBP1,and S6K1 in the T treatment group increased significantly (P＜0.01),but the relative expression of CAT1 decreased significantly (P＜0.01).LPS significantly reduced the relative expression of CAT1,LAT1,STAT5,mTOR,and 4EBP1 (P＜0.01 or P＜0.05),whereas tricin supplementation significantly increased the relative expression of STAT5 in cells induced by LPS (P＜0.01).In conclusion,tricin increased the viability of BMECs and promoted lacto-protein gene expression in cells cultured in a medium without LPS.LPS elevated inflammatory gene expression and inhibited lacto-protein gene expression in BMECs.Tricin inhibited inflammatory gene expression;however,it did not improve lacto protein gene expression in BMECs inhibited by LPS.%为分析苜蓿素对脂多糖诱导下体外培养奶牛乳腺上皮细胞抗炎和乳蛋白合成相关基因表达的影响,本研究将体外培养的奶牛乳腺上皮细胞分成4组,即基础培养基(对照)和基础培养基中分别加入1μg·mL-1 LPS(L)、1μg·mL-1 LPS+10 μg·mLL1苜蓿素(L+T)和10 μg·mL1苜蓿素(T).结果显示,1)与对照组相比,L组奶牛乳腺上皮细胞的活性显著下降(P＜0.05),而T组则显著升高(P＜0.01).2)L+T组细胞的超氧化物歧化酶(SOD)活性显著高于L组(P＜0.01),而一氧化氮(NO)、丙二醛(MDA)含量则显著低于L组(P＜0.01).3)LPS能够显著升高细胞的白细胞介素1β(IL-1β)、IL-6、肿瘤坏死因子α(TNF-α)、Toll样受体2(TLR2)、TLR4和髓样分化因子88 (MyD88)表达水平(P＜0.01),而添加苜蓿素能够显著降低IL-1β、TNF-α、TLR2和TLR4的表达水平(P＜0.01).4)与对照组相比,T组细胞的酪氨酸激酶2 (JAK2)、信号转导子和转录激活子5(STAT5)、雷帕霉素靶蛋白(mTOR)、真核细胞始动因子4E结合蛋白1(4EBP1)和核糖体S6蛋白激酶1(S6K1)表达量显著升高(P＜0.01),而碱性氨基酸转运载体1(CAT1)表达量显著降低(P＜0.01).LPS能够显著降低细胞的CA T1、L型氨基酸转运载体1(LA T1)、STAT5、mTOR和4EBP1表达水平(P＜0.01或P＜0.05),而添加苜蓿素能够显著升高STAT5表达水平(P＜0.01).结果表明,乳腺细胞在LPS刺激下,导致细胞内炎症因子基因表达升高和抑制乳蛋白合成相关基因的表达,而添加苜蓿素能够抑制乳腺细胞内炎症因子基因表达,但对乳蛋白合成的相关基因表达作用不明显;无LPS刺激下,添加苜蓿素能够提高乳腺细胞活性和促进乳蛋白合成相关基因的表达.
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