【作者】 寇洁；

【导师】 王继文；

【作者基本信息】 四川农业大学 ， 动物遗传育种与繁殖， 2013， 博士

【摘要】 皮下脂肪组织是脂质沉积的主要部位,在稳定机体代谢平衡中起着重要作用。然而,皮下脂肪组织的整体发育规律缺乏系统的认识,不同部位皮下脂肪组织发育差异的原因也不明确。本研究以北京鸭为研究材料,首先,分别从组织TG沉积能力、脂肪细胞增殖和分化能力及脂滴发育能力来揭示皮下脂肪组织的整体发育规律；其次,通过采用短期禁食和静脉注射LPS建立诱导脂肪代谢异常的模型,初步探讨不同部位皮下脂肪组织发育差异的原因；第三,通过克隆与血管发育、TG水解酶代谢相关的ANGPTL3和ANGPTL4序列,探讨其表达量与不同部位皮下脂肪组织TG含量、脂肪细胞直径间的关系。取得的主要结果和结论如下：(1)1-8周龄肉鸭皮下脂肪组织的整体发育规律呈现为4周龄前脂肪组织的脂质沉积由脂肪细胞增殖和肥大共同作用,而4周龄后主要依赖于脂肪细胞的肥大。(2)肉鸭不同部位皮下脂肪组织的发育规律存在显著差异,主要体现在脂肪细胞增殖及脂质沉积能力(即脂肪细胞肥大、脂滴合成能力和组织TG含量)方面。其中,颈部皮下脂肪组织(NSF)具有较强的脂肪细胞增殖和脂滴合成能力,胸部皮下脂肪组织(CSF)及背部皮下脂肪组织(BSF)的脂滴合成能力相对较强,腹部皮下脂肪组织(ASF)和腿部皮下脂肪组织(LSF)分别在4-8周龄及3-4周龄时呈现出较强的脂肪细胞肥大和增殖能力。此外,BSF和LSF组织TG含量显著低于NSF, CSF和ASF。(3)短期禁食导致肉鸭脂质代谢异常,引起总TG、总TC、NEFA、VLDL、 HDL-C、LDL-C等参数及肝素后总LPL酶活性显著变化。(4)静脉注射LPS显著改变肉鸭生长性能和血脂代谢水平,诱使不同部位皮下脂肪组织TG沉积、脂肪细胞增殖与肥大及脂滴发育能力发生变化,这与TG水解酶类的调控有关。NSF中LPL酶活性显著升高,LPL基因mRNA表达水平出现了下调；CSF中LPL酶活性显著升高,LPL、ATGL、ADRP和PLIN基因的mRNA表达水平出现了下调；ASF中LPL、ATGL和PLIN基因mRNA表达水平均出现了下调;BSF中,LPL、ATGL、ADRP和PLIN基因mRNA表达水平均出现了下调；LSF中LPL、ADRP和PLIN基因的mRNA表达水平显著升高。(5)本研究成功克隆获得ANGPTL3和ANGPTL4基因部分序列,长度分别为1372bp和726bp。ANGPTL3和ANGPTL4在不同部位皮下脂肪组织中的发育性表达模式存在明显差异。其中,ANGPTL3表达水平与CSF中的细胞直径呈负相关,与NSF中的组织TG含量呈正相关,ANGPTL4表达水平与LSF中的组织TG含量呈正相关,初步证实两者均参与了肉鸭皮下脂肪组织的发育过程,且与不同部位皮下脂肪组织发育差异有关。更多还原

【Abstract】 The subcutaneous adipose tissue is the main organ for lipid deposition and plays an important role in stabilizing metabolic balance. However, the developmental patterns of subcutaneous adipose tissue during Peking duck (Anas platyrhynchos) early development, as well as the reasons for regional differences were not well known. Therefore, we employed Peking duck as materials to investigate the characteristics of subcutaneous adipose tissue formation, and analysis the growing pattern of subcutaneous adipose tissue during duck early growing stages from week1to8, comparing the morphological characteristics and lipid contents in five regions of subcutaneous adipose tissue including neck area (NSF), chest area (CSF), lower abdomen area (ASF), back area (BSF) and leg area (LSF). The mRNA expressions of three molecular maker genes including47-kDa tail interacting protein (TIP47), adipose differentiation-related protein (ADRP) and Perilipin were also detected using quantitative real-time (qRT)-PCR method. In order to investigate the reasons for regional differences of subcutaneous adipose tissue, we analysis the lipid metabolic disorder by using fasting and LPS injection technique. We use RT-PCR method to clone partial cDNA of duck ANGPTL3and ANGPTL4, as well as to analysis the expressions of these genes during duck growth, to investigate correlations between the gene expressions and regional differences of subcutaneous adipose development. The main results of this study are as follows:(1) A combination of adipocyte hyperplasia and hypertrophy is mainly responsible for the development of duck adipose tissue before4weeks of age, after which adipose expansion is accomplished by adipocyte hypertrophy only.(2) There are many regional differences in adipocyte hyperplastic capacity, as well as fat storage capacities (capacities from adipocyte hypertrophy, lipid synthesis and lipid deposition). Adipocytes in NSF have a higher hyperplastic and lipogenic activity compared with these from other regions. Adipocytes in CSF also have a higher lipogenic activity than that in other regions during the early stage of development. Adipocytes in ASF have a higher hypertrophy capacity at week4to8. The greater fat storage capacity in NSF, CSF, ASF are observed compared with these in BSF, LSF at week1to8. In contrast, adipocytes in BSF region have a higher lipogenic activity than other regions during the early stage of development. Adipocytes in LSF region have a higher hyperplastic capacity at week3to4, a higher hypertrophy capacity at week4to8, and a higher metabolic activity at week3to5, whereas the lower performance in fat storage capacity.(3)12hours fasting could induce lipid metabolic disorder. The duck serum total TG, total TC, NEFA, VLDL, HDL-C, LDL-C levels and post-heparin plasma LPL activity showed significant change.(4) Intravenous injection of LPS may have an adverse effect on the duck growth performance and lipid metabolism and could induce regional differences of subcutaneous adipose tissue in fat storage capacity, adipocyte hyperplasia and hypertrophy activity, as well as lipid metabolic activity. TG hydrolases may take part in this metabolic process. Compared with control groups, NSF region in LPS injection groups had a higher LPL activity and lower LPL mRNA levels. CSF region had a higher LPL activity and lower LPL, ATGL, ADRP and PLIN mRNA levels. CSF region had a lower LPL, ATGL and PLIN mRNA levels. BSF region had a lower LPL, ATGL, ADRP and PLIN mRNA levels. However, LSF had a higher LPL, ATGL, ADRP and PLIN mRNA levels.(5) We have got partial cDNA sequences. Results showed that duck ANGPTL3contained1372bp nucleotide and ANGPTL4contained726bp nucleotide. There are significant differences in developmental expression patterns of ANGPTL3and ANGPTL4. The ANGPTL3mRNA levels were negatively correlated with adipocyte diameter in CSF and were positively correlated with the lipid content in NSF. The ANGPTL4mRNA levels were positively correlated with the lipid content in LSF. Results suggested that both ANGPTL3and ANGPTL4coule be related to the development of subcutaneous adipose tissue and contribute to regional differences during duck growth.更多还原