Engel Kathrin M, Schiller Jürgen, Müller Karin, Dannenberger Dirk, Jakop Ulrike
Institute of Medical Physics and Biophysics, Faculty of Medicine, University of Leipzig, Härtelstr. 16/18, 04107, Leipzig, Germany.
Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315, Berlin, Germany.
Lipids. 2017 Oct;52(10):857-869. doi: 10.1007/s11745-017-4283-9. Epub 2017 Aug 11.
Cryopreservation of kangaroo sperm has not been successful so far, and yet there is no promising cryopreservation protocol for these cells available. However, conservation of gametes is extremely important, particularly in the context of preserving endangered species. As spermatozoa are comprised of different membrane systems, the composition of these membranes might account for difficulties in cryopreservation. Lipids, as the main components, affect the physical properties of biological membranes and play a major role in sperm maturation. Therefore, knowledge of the lipid composition is crucial for any further step toward the preservation of the species. We used MALDI-TOF, ESI-IT, tandem mass spectrometry, and thin layer chromatography to investigate the lipid composition of epididymal spermatozoa of four different kangaroo species. Spectra of these species were very similar with respect to the identified lipid species. Tremendous changes in the lipid composition during the transit of sperm from caput to cauda epididymis could be seen, specifically an increase in poly-unsaturated fatty acids, ether lipids, and plasmalogens, as well as a reduction in mono- and di-unsaturated fatty acids. Additionally, phosphatidylcholines containing docosatrienoic acid (22:3), a heretofore unknown fatty acid for sperm membranes, showed the highest abundance in kangaroo sperm.
到目前为止，袋鼠精子的冷冻保存尚未成功，而且目前还没有适用于这些细胞的有前景的冷冻保存方案。然而，配子的保存极其重要，特别是在保护濒危物种的背景下。由于精子由不同的膜系统组成，这些膜的组成可能是冷冻保存困难的原因。脂质作为主要成分，影响生物膜的物理性质，并在精子成熟中起主要作用。因此，了解脂质组成对于该物种保存的任何进一步步骤都至关重要。我们使用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）、电喷雾离子阱（ESI-IT）、串联质谱和薄层色谱法来研究四种不同袋鼠物种附睾精子的脂质组成。就已鉴定的脂质种类而言，这些物种的光谱非常相似。可以看到精子从附睾头向附睾尾转运过程中脂质组成发生了巨大变化，特别是多不饱和脂肪酸、醚脂和缩醛磷脂增加，以及单不饱和脂肪酸和二不饱和脂肪酸减少。此外，含有二十二碳三烯酸（22:3）的磷脂酰胆碱（一种迄今为止在精子膜中未知的脂肪酸）在袋鼠精子中含量最高。
