本试验旨在研究乙酸浓度对奶牛乳腺上皮细胞甘油三酯(TAG)含量及瘦素(leptin)和过氧化物酶增殖物激活受体γ(PPARγ)基因表达量的影响。将传至第3代的奶牛乳腺上皮细胞以1×105个/孔的密度培养48 h后,随机分为6个处理,各处理分别采用乙酸浓度为0(对照组)、4、6、8、10和12 mmol/L的培养液。置于37 ℃ 5% CO2培养箱继续培养48 h。收集细胞,观测脂滴形成状况,测定TAG含量及leptin和PPARγ基因表达量。结果表明:随乙酸浓度的增加,培养的奶牛脂肪前体细胞脂滴形成增多;随乙酸浓度的增加,TAG含量和PPARγ基因表达量均呈显著的线性或二次曲线增加(P<0.05),且以乙酸浓度为10和12 mmol/L时效果较好;一定浓度的乙酸可上调leptin基因表达量,尤以浓度为8、10 mmol/L时上调作用较好。结果提示,乙酸对奶牛乳腺上皮细胞内脂滴的形成、TAG的积累、leptin和PPARγ基因的表达有显著的促进作用。本试验条件下,乙酸浓度为10~12 mmol/L时能较好地促进PPARγ基因的表达,浓度为8~10 mmol/L时能较好地促进leptin基因的表达。
This study was conducted to determine the effects of acetate concentration on triacylglycerol (TAG) content, as well as expression levels of leptin and peroxisome proliferator-activated receptor-γ (PPARγ) genes in bovine mammary epithelial cells (BMECs). The 3th passage BMECs with a density of 1×105 cells/well were cultured for 48 h, then cells were divided into six treatments. Culture mediums containing different concentrations of acetate (0, 4, 6, 8, 10 and 12mmol/L) were used in each treatment, respectively. Cells were continuous incubated in an incubator with 5% CO2 at 37 ℃ for 48 h, then were collected for the analysis of lipid droplet formation, TAG content, and expression levels of leptin and PPARγ genes. The results showed as follows: with the increase of acetate concentration, lipid droplets was increased in BMECs; TAG content and PPARγ gene expression level were significantly increased linearly or quadratically (P<0.05), and 10 and 12 mmol/L were optimal concentrations; leptin gene expression level was up-regulated by acetate at a certain concentration, and 8 and 10 mmol/L were optimal concentrations. In conclusion, acetate can stimulate lipid droplet formation, TAG accumulation and expression levels of leptin and PPARγ genes in BMECs; in the present study, 10 to 12 mmol/L acetate has better effects on PPARγ gene expression, and 8 to 10 mmol/L acetate has better effects on leptin gene expression.
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