Nilsson Emeli M, Fainberg Hernan P, Choong Siew S, Giles Thomas C, Sells James, May Sean, Stansfield Fiona J, Allen William R, Emes Richard D, Mostyn Alison, Mongan Nigel P, Yon Lisa
Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom.
Advanced Data Analysis Centre, University of Nottingham, Sutton Bonington, United Kingdom.
PLoS One. 2014 Mar 14;9(3):e91717. doi: 10.1371/journal.pone.0091717. eCollection 2014.
Adipose tissue (AT) is a dynamic and flexible organ with regulatory roles in physiological functions including metabolism, reproduction and inflammation; secreted adipokines, including leptin, and fatty acids facilitate many of these roles. The African elephant (Loxodonta africana) is experiencing serious challenges to optimal reproduction in captivity. The physiological and molecular basis of this impaired fertility remains unknown. AT production of leptin is a crucial molecular link between nutritional status, adiposity and fertility in many species. We propose that leptin has a similar function in the African elephant. African elephant visceral and subcutaneous adipose tissue (AT) was obtained from both sexes and a range of ages including females with known pregnancy status. RNA was extracted and histological sections created and analyzed by microarray, PCR and immunohistochemistry respectively. Gas-chromatography was used to determine the fatty acid composition of AT. Microarray expression profiling was used to compare gene expression profiles of AT from pre-pubertal versus reproductively competent adult African elephants. This study demonstrates, for the first time, leptin mRNA and protein expression in African elephant AT. The derived protein sequence of the elephant leptin protein was exploited to determine its relationship within the class I helical cytokine superfamily, which indicates that elephant leptin is most closely related to the leptin orthologs of Oryctolagus cuniculus (European rabbit), Lepus oiostolus (woolly hare), and members of the Ochotonidae (Pika). Immunohistological analysis identified considerable leptin staining within the cytoplasm of adipocytes. Significant differences in fatty acid profiles between pregnant and non-pregnant animals were revealed, most notably a reduction in both linoleic and α linoleic acid in pregnant animals. This report forms the basis for future studies to address the effect of nutrient composition and body condition on reproduction in captive and wild elephants.
脂肪组织（AT）是一个动态且灵活的器官，在包括新陈代谢、生殖和炎症等生理功能中发挥调节作用；分泌的脂肪因子，包括瘦素和脂肪酸，促进了其中许多作用。非洲象（Loxodonta africana）在圈养环境中，其最佳繁殖面临严峻挑战。这种生育能力受损的生理和分子基础仍不清楚。在许多物种中，脂肪组织产生的瘦素是营养状况、肥胖和生育能力之间的关键分子联系。我们推测瘦素在非洲象中具有类似功能。从不同性别和年龄范围的非洲象获取了内脏和皮下脂肪组织（AT），包括已知怀孕状态的雌性。分别提取RNA，并制作组织切片，通过微阵列、聚合酶链反应（PCR）和免疫组织化学进行分析。使用气相色谱法测定脂肪组织的脂肪酸组成。利用微阵列表达谱比较青春期前和具有生殖能力的成年非洲象脂肪组织的基因表达谱。本研究首次证明了非洲象脂肪组织中瘦素mRNA和蛋白质的表达。利用大象瘦素蛋白的推导蛋白质序列来确定其在I类螺旋细胞因子超家族中的关系，这表明大象瘦素与穴兔（欧洲兔）、藏兔（毛兔）的瘦素直系同源物以及鼠兔科（鼠兔）成员关系最为密切。免疫组织学分析在脂肪细胞的细胞质中发现了大量瘦素染色。揭示了怀孕和未怀孕动物之间脂肪酸谱的显著差异，最明显的是怀孕动物中油酸和α - 亚麻酸均减少。本报告为未来研究营养成分和身体状况对圈养和野生大象繁殖的影响奠定了基础。
