催乳素对奶牛乳腺上皮细胞乳脂和乳蛋白合成相关基因表达的影响

本试验旨在探讨催乳素对奶牛乳腺上皮细胞(BMECs)乳脂和乳蛋白合成相关基因表达的影响。选取中国荷斯坦奶牛BMECs为试验材料,经纯化培养后,培养基中添加不同浓度催乳素[0(对照)、100、300、500和1 000 ng/m L],继续培养24 h。通过四甲基偶氮唑盐(MTT)比色法检测细胞活力;利用试剂盒检测胞内甘油三酯的含量;采用实时定量PCR法检测乳脂和乳蛋白合成相关基因的表达。结果表明:1)催乳素浓度为100、300 ng/m L时,BMECs相对增殖率显著高于对照组与其他试验组(P0.05)。2)与对照组相比,300 ng/m L催乳素能够显著提高BM ECs乙酰辅酶A羧化酶(ACC)、二酰甘油酰基转移酶(DG AT)、脂肪酸结合蛋白3(FABP3)基因表达量及甘油三酯的含量(P0.05),硬脂酰辅酶A去饱和酶(SCD)、过氧化物酶体增殖物激活受体γ(PPARγ)基因表达量有增加的趋势。3)与对照组相比,100、300 ng/m L催乳素能够显著提高哺乳动物雷帕霉素靶蛋白(m TOR)、催乳素受体(PRLR)基因表达量(P0.05);300 ng/m L催乳素能显著提高αS1酪蛋白(CSN1 S1)基因表达量(P0.05)。综上所述,100~300 ng/m L的催乳素对BM ECs乳脂和乳蛋白合成有较好的促进效果。

Effects of Prolactin on Gene Expressions Involved in Milk Fat and Milk Protein Synthesis in Bovine Mammary Epithelial Cells

The aim of this study was to determine the effects of prolactin on gene expressions involved in milk fat and milk protein synthesis in bovine mammary epithelial cells ( BMECs) . mammary epithelial cells of Chi?nese Holstein cows were used, after purification culture, different concentrations [ 0 ( control) , 100, 300, 500 and 1 000 ng/mL] of prolactin were added in culture medium for a 24 h cultivation. Cell viability was de?tected by thiazoly blue tetrazolium bramide ( MTT);triglyceride ( TAG) content was measured by using TAG determination kit; gene expressions involved in milk fat and milk protein synthesis were measured by real?time quantitative PCR ( RT?qPCR) . The results showed as follows: 1) 100 and 300 ng/mL prolactin significantly promoted the proliferation of BMECs compared with control and other experimental groups ( P<0.05) . 2) The content of TAG in BMECs and gene expressions of acetyl?CoA carboxylase ( ACC) , diacylgycerol acyltrans?ferase ( DGAT) , fatty acid?binding protein 3 ( FABP3) were significantly higher in 300 ng/mL prolactin group compared with those in control group (P<0.05), and gene expressions of stearoyl?coenzyme A desaturase ( SCD) and peroxisome proliferator?activated receptor γ ( PPARγ) tended to be higher. 3 ) Compared with control group, 100 and 300 ng/mL prolactin significantly upregulated gene expressions of mammalian target of rapamycin ( mTOR) and prolactin receptor ( PRLR) ( P<0.05) , and 300 ng/mL prolactin significantly upreg?ulated αS1 casein ( CSN1S) gene expression ( P<0.05) . In conclusion, 100 to 300 ng/mL prolactin is an opti?mal level considering its improvement effects on milk fat and milk protein synthesis.