Abstract：
The aim of the study was to investigate the relationship between ooplasm morphology, lipid content, glucose-6-phosphate dehydrogenase activity (G6PDH) and maturation potential of domestic cat oocytes. Cumulus-oocyte complexes were classified according to ooplasm morphology: evenly dark (dCOC), heterogeneous/mosaic (hCOC), or light/transparent (lCOC), however only dCOCs are thought to be the best-quality, the remaining ones are usually rejected, therefore little is known about their intracellular properties. Lipid droplets (LDs) were visualized and quantified using Oil Red O. G6PDH activity was assessed before in vitro maturation (IVM), using the brilliant cresyl blue (BCB) test. IVM-control oocytes underwent IVM without BCB staining. The dCOCs and hCOCs had different patterns of LD spatial distribution, but similar amounts of lipid, although this tended towards being lower in hCOCs. Low G6PDH activity (BCB+) was observed in 74 %, 60 % and 24 % (P < 0.01) of dCOCs, hCOCs, and lCOCs, respectively. Significantly more BCB+ /oocytes than BCB-/oocytes reached the metaphase II stage in all groups. The maturation rate of BCB+ /hCOCs was higher than that of IVM/hCOC-controls (40 % v.s. 20 %, P < 0.001), and was comparable to that of BCB+ /dCOCs (54 %; P > 0.05). lCOCs were the smallest (P < 0.01), contained fewer (P < 0.01) lipids than dCOCs or hCOCs, and displayed reduced maturational potential. Overall, LD content and distribution, as well as G6PDH activity, in cat oocytes were strongly associated with ooplasm morphology and oocyte maturational competence. Deeper understanding of the intrinsic properties of oocytes with different ooplasm morphology using the domestic cat model, may be particularly important in the context of the conservation of endangered felids.
摘要：
这项研究的目的是探讨卵质形态之间的关系，脂质含量，家猫卵母细胞的葡萄糖-6-磷酸脱氢酶活性（G6PDH）和成熟潜力。根据卵质形态对卵丘-卵母细胞复合物进行分类：均匀黑暗（dCOC），异质/马赛克(hCOC)，或光/透明（lCOC），然而，只有dCOC被认为是最好的质量，剩下的通常被拒绝，因此，人们对它们的细胞内特性知之甚少。使用油红O对脂滴（LD）进行可视化和定量。在体外成熟（IVM）之前评估G6PDH活性，使用亮甲酚蓝（BCB）测试。IVM对照卵母细胞在没有BCB染色的情况下经历IVM。dCOC和hCOC具有不同的LD空间分布模式，但是相似量的脂质，尽管这在hCOC中趋于较低。低G6PDH活性（BCB+）在74%观察到，60%和24%(P<0.01)的dCOCs，hCOCs,和LCOC，分别。在所有组中，达到中期II期的BCB/卵母细胞明显多于BCB-/卵母细胞。BCB+/hCOCs的成熟率高于IVM/hCOC对照(40%对20%,P<0.001)，与BCB+/dCOCs相当(54%；P>0.05)。lCOCs最小(P<0.01)，脂质含量低于dCOCs或hCOCs（P<0.01），并显示出降低的成熟潜力。总的来说,LD含量和分布，以及G6PDH活性，在猫中，卵母细胞与卵质形态和卵母细胞成熟能力密切相关。使用家猫模型对具有不同卵质形态的卵母细胞的内在特性有了更深入的了解，在保护濒临灭绝的猫科动物的背景下可能尤为重要。
