维生素A对过氧化氢诱导的奶牛乳腺上皮细胞内乳脂合成的影响

Effects of Vitamin A on Milk Fat Synthesis in Bovine Mammary Epithelial Cells Induced by Hydrogen Peroxide

本试验旨在研究维生素A对过氧化氢(H_(2)O_(2))诱导的奶牛乳腺上皮细胞(BMECs)内乳脂合成的影响。试验采用单因子完全随机试验设计,将第3代BMECs随机分为9个组,每组6个重复。其中,对照组(CON组)用生长培养基培养30 h;H_(2)O_(2)损伤组(H_(2)O_(2)组)用CON组培养基培养24 h后,再加入H_(2)O_(2)继续培养6 h;7个维生素A预保护组则在CON组培养基中添加不同浓度维生素A培养24 h后,再加入H_(2)O_(2)继续培养6 h,维生素A浓度分别为0.05(0.05 VAH组)、0.10(0.1VAH组)、0.20(0.2VAH组)、0.50(0.5VAH组)、1.00(1VAH组)、2.00(2VAH组)和4.00μg/mL(4VAH组)。结果显示:与CON组相比,H_(2)O_(2)组诱导BMECs发生氧化损伤,BMECs的相对增殖率(RGR)、甘油三酯(TG)含量、总抗氧化能力(T-AOC)以及总超氧化物歧化酶(T-SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)、硫氧还蛋白还原酶1(TrxR1)、脂肪酸合成酶(FASN)、脂酰辅酶A去饱和酶(SCD)、脂蛋白酯酶(LPL)和乙酰辅酶A羧化酶(ACC)活性显著降低(P≤0.05),ACC、FASN、谷胱甘肽过氧化物酶1(GPx1)、谷胱甘肽过氧化物酶4(GPx4)、TrxR1、过氧化酶体增殖物激活受体γ(PPARγ)、固醇调节元件结合蛋白1(SREBP1)相对表达量显著降低(P≤0.05),但活性氧(ROS)活性显著提高(P≤0.05)。与H_(2)O_(2)组相比,0.2VAH~2VAH组BMECs的RGR和GPx1、GPx4、TrxR1、LPL、SCD、FASN、PPARγ和SREBP1相对表达量以及GPx活性和T-AOC显著提高(P≤0.05),并且1VAH组的TG含量、T-SOD和CAT活性显著提高(P≤0.05),且1VAH组的ROS活性显著降低(P≤0.05)。由此可见,维生素A对由H_(2)O_(2)诱导引起的BMECs内抗氧化能力下降、乳脂从头合成和脂肪酸摄取相关酶活性及其基因表达的下调具有剂量依赖性的减缓效果,以0.20~2.00μg/mL维生素A的效果较好,尤以1.00μg/mL维生素A的效果最好。

The purpose of this experiment was to study the effects of vitamin A on milk fat synthesis in bovine mammary cells(BMECs)induced by hydrogen peroxide(H_(2)O_(2)).This experiment was designed with a single-factor completely randomized trial.The third-generation BMECs were randomly divided into 9 groups with 6 replicates in each group.Among them,the control group(CON group)was cultured with growth medium for 30 h,the H_(2)O_(2)injury group(H_(2)O_(2)group)was cultured with CON group medium for 24 h,and then H_(2)O_(2)was added to continue the culture for 6 h.The seven vitamin A pre-protection groups were cultured for 24 h with different concentrations of vitamin A in the CON group medium,and then added H_(2)O_(2)for 6 h,the vitamin A concentration was 0.05(0.05VAH group),0.10(0.1VAH group),0.20(0.2VAH group),0.50(0.5VAH group),1.00(1VAH group),2.00(2VAH group)and 4.00μg/mL(4VAH group),respectively.The results showed that compared with the CON group,the H_(2)O_(2)induced oxidative damage to BMECs,the relative growth rate(RGR),triglyceride(TG)content,total antioxidant capacity(T-AOC)and the activities of total superoxide dismutase(T-SOD),catalase(CAT),glutathione peroxidase(GPx),thioredoxin reductase 1(TrxR1),fatty acid synthase(FASN),acyl-CoA desaturase(SCD),lipoprotein esterase(LPL)and acetyl-CoA carboxylase(ACC)activities of BMECs in the H_(2)O_(2)group were significantly reduced(P≤0.05),and the relative expression levels of ACC,FASN,glutathione peroxidase 1(GPx1),glutathione peroxidase 4(GPx4),thioredoxin reductase 1(TrxR1),peroxisome proliferator-activated receptorγ(PPARγ),sterol regulatory element binding protein 1(SREBP1)were significantly reduced(P≤0.05),but the activity of reactive oxygen species(ROS)was significantly increased(P≤0.05).Compared with the H_(2)O_(2)group,the RGR and the relative expression levels of GPx1,GPx4,TrxR1,LPL,SCD,FASN,PPARγand SREBP1 and the GPx activity,T-AOC of the BMECs in the 0.2VAH to 2VAH groups were significantly increased(P≤0.05),and the TG content,T-SOD and CAT activities of the BMECs in the 1VAH group were significantly increased(P≤0.05),while the ROS activity of the BMECs in the 1VAH group was significantly reduced(P≤0.05).It can be seen that vitamin A has a dose-dependent mitigating effect on the decrease in antioxidant capacity,enzyme activities and gene expressions associated with the de novo synthesis of milk fat and fatty acid uptake in BMECs by H_(2)O_(2)-induced damage.The vitamin A of 0.20 to 2.00μg/mL has better effect,especially the vitamin A of 1.00μg/mL has the best effect.