不同品种猪PPARγ和C/EBPα基因表达规律与肌内脂肪含量的相关

摘要

[Objective]The objectives of this study were to investigate the developmental changes of the PPARγ and C/EBPαmRNA expression level in different tissues, months and breeds, and its effect on intramuscular fat accumulation in pig. [Method]Jiangkou Luobo Pig, Congjiang Xiang Pig and Large White Pig were slaughtered at 3, 4, 5, 6, and 7 months to collect samples from heart, liver, spleen, lung, kidney, small intestine, longissimus dorsi, and subcutaneous adipose for the purpose of determing the IMF content in longissimus dorsi and extracting total RNA in order to investigate the developmental changes of the PPARγ and C/EBPαexpression by real - time PCR.[Result]By real-time PCR, PPARγ and C/EBPα had the mRNA expression in all tissues of Large White Pig at 3, 4, 5, 6, and 7 months, but highly in liver, small intestine, longissimus dorsi, subcutaneous adipose, lowly in heart, spleen, lung, and kidney. The expression levels of PPARγ in the small intestine, longissimus dorsi, and subcutaneous adipose at 3, 4 months were extremely different with that at 6 and 7 months (P<0.01). The expression levels of C/EBPα in the liver, lung, small intestine, and subcutaneous adipose at 3 month was extremly different with that at 6 and 7 months (P<0.01); The mRNA expression of PPARγ and C/EBPα were lower in heart, spleen, lung, kidney, and longissimus dorsi of Jiangkou Luobo Pig, higher in subcutaneous adipose with issue-specificity. The expression amount increased with the age, and the increase of subcutaneous fat was the most. The expression levels of PPARγ in the small intestine, longissimus dorsi, and subcutaneous adipose at 3 and 4 months also were extremely different with that at 6 and 7 months (P<0.01). The expression levels of C/EBPα in the small intestine, subcutaneous adipose at 3 month were extremely different with that at 5, 6, and 7 months (P<0.01). The mRNA expression of PPARγ and C/EBPαin the subcutaneous adipose of Congjiang Xiang Pig was the highest. The expression of PPARγ was not significantly increased with the age. The expression of C/EBPα was significantly increased with the age. The expression levels of PPARγ and C/EBPα in the small intestine, longissimus dorsi, and subcutaneous adipose at 3, 4 months were different with that at 6 and 7 months (P<0.05). With growing, the mRNA expression levels of PPARγ and C/EBPα were basically the same in the model, and showed an increasing trend, then maintained the higher expression levels in 6 and 7 months. The mRNA expression levels of PPARγ and C/EBPα were gradually increased with the increase of the age and maintained a relatively stable level at the late growth stage. The expression of PPARγ and C/EBPα was the highest in subcutaneous adipose, the higher in liver, lung, small intestine, and the lowest in heart, spleen, and kidney. The PPARγ and C/EBPα mRNA expression in different tissues of Jiangkou Luobo Pig, Congjiang Xiang Pig were higher than that of Large White Pig. The correlation of gene expression and IMF content showed that the PPARγ and C/EBPα expression level were positively related to IMF content.[Conclusion]It was inferred that PPARγ and C/EBPα gene may be related to regulatory mechanism of lipid metabolism and fat deposition.%[目的]研究PPARγ 和C/EBPα 基因在猪不同组织、月龄和品种中mRNA的表达规律,结合屠宰试验分析PPARγ 和C/EBPαmRNA表达水平对肌内脂肪沉积的影响.[方法]选取3—7月龄的江口萝卜猪、从江香猪和大白猪为试验材料,提取心、肝、脾、肺、肾、小肠、背最长肌和皮下脂肪的总RNA,应用实时荧光定量PCR技术检测PPARγ 和C/EBPα 基因在3个品种不同月龄各组织中mRNA的相对表达量,同时测定背最长肌中的肌内脂肪含量.[结果]PPARγ、C/EBPα 在大白猪3—7月龄各组织中均有表达,其中肝、小肠、背最长肌、皮下脂肪的表达水平较高,心、脾、肺、肾的表达水平较低.其中PPARγ 在小肠、背最长肌、皮下脂肪中3、4月龄分别与6、7月龄的表达量差异极显著(P<0.01).C/EBPα 在肝、肺、小肠、皮下脂肪中3月龄与6、7月龄均差异极显著(P<0.01);PPARγ、C/EBPα 在江口萝卜猪心、脾、肺、肾、背最长肌的表达量最低,在皮下脂肪中最高,具有组织特异性.其表达量随月龄递增而上升,皮下脂肪的增加幅度最大.其中PPARγ 在小肠、背最长肌、皮下脂肪中3、4月龄与6、7月龄的表达量差异极显著(P<0.01).C/EBPα 在小肠、皮下脂肪中3月龄与5、6、7月龄的表达量均差异极显著(P<0.01);PPARγ、C/EBPα 在从江香猪心、肝、脾、肺、肾、小肠、背最长肌的表达量较低,在皮下脂肪的表达量最高,PPARγ 的表达量随月龄增加而上升的幅度较小,C/EBPα 的表达量在各组织中的表达量随时间增加而上升.其在小肠、皮下脂肪、背最长肌中3、4月龄与6、7月龄的表达量差异极显著(P<0.01);PPARγ 和C/EBPα基因在各组织均有表达,组织间的表达量存在差异,其中在肝、小肠、皮下脂肪中为高丰度表达.随着月龄的增加,PPARγ 和C/EBPα 基因mRNA的表达模式基本相同,总体呈现上升趋势,6、7月龄的表达水平较高,即随着月龄的增加而逐渐上升,到生长后期维持一个相对稳定水平.总体上皮下脂肪的表达量最高,其次肝、肺、小肠、背最长肌中较高,心、脾、肾中的表达量最低;不同品种间PPARγ、C/EBPα 在相同月龄各组织中的表达量存在差异,总体上大白猪中肝、小肠、皮下脂肪中PPARγ 和C/EBPαmRNA的表达量分别与江口萝卜猪、从江香猪差异显著;肌内脂肪含量随着月龄的增加持续上升,不同品种间肌内脂肪含量存在差异,其中江口萝卜猪和从江香猪较高.不同品种猪PPARγ 和C/EBPα 基因的表达量与肌内脂肪含量的相关性分析表明,不同时期基因的表达量与肌内脂肪含量呈不同程度正相关.[结论]猪PPARγ 和C/EBPα 基因在不同组织、时期和品种中的表达差异可能与脂质代谢和脂肪沉积有关.