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适宜的密度培养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 proper densities 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 PPARy 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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