Leptin promotes meiotic progression and developmental capacity of bovine oocytes via cumulus cell-independent and -dependent mechanisms
Leptin promotes meiotic progression and developmental capacity of bovine oocytes via cumulus cell-independent and -dependent mechanisms
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DOI：
10.1095/biolreprod.106.054551
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发表时间：
2007-03-01
影响因子：
3.6
通讯作者：
Wolf, Eckhard
中科院分区：
文献类型：
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作者：
Paula-Lopes, Fabiola F.;Boelhauve, Marc;Wolf, Eckhard
瘦素已被证明在牛卵母细胞成熟过程中发挥积极作用，影响囊胚发育、细胞凋亡和发育重要基因的转录水平。本研究旨在进一步研究瘦素对卵母细胞的作用机制以及卵丘细胞(CCS)在其中的作用。在第一组实验中，卵丘-卵母细胞复合体(COCs)在含有0、1或10 ng/ml瘦素的无血清培养液中成熟，或在添加10%(v/v)发情牛血清(ECS)的培养液中成熟。1和10 ng/ml的瘦素浓度刺激卵母细胞的减数分裂进程。此外，TUNEL染色显示，这些剂量的瘦素降低了CCS的凋亡率。在第二组实验中，COCs或裸卵母细胞在0或10 ng/mlLeptin的存在下成熟。瘦素可增加极体脱出的COCs和DO的比例。相反，瘦素对受精率和囊胚发育的积极作用仅在COCs治疗后观察到，而在DOS治疗后观察不到。即使在卵母细胞孤雌激活或在受精前去除CCS后，瘦素对COCs的治疗仍能持续促进囊胚发育。瘦素处理和去卵母细胞不影响多精卵母细胞的比例。在第三系列实验中，COCs在0、1或10 ng/mlLeptin的存在下成熟。用逆转录定量聚合酶链式反应(RT-qPCR)分析卵丘细胞和单个卵母细胞的特异性基因转录水平。瘦素治疗可增加卵母细胞中Fas、FASLG和STAT3转录水平，但不影响LEPR、Bax和BIRC4的mRNA浓度。在卵丘细胞中，瘦素处理增加了LEPR、STAT3、Bax、BIRC4和Fas的mRNA水平，但不改变FASLG mRNA的丰度。综上所述，瘦素对卵母细胞和卵丘细胞的基因表达有不同的调节作用。此外，瘦素通过卵丘细胞非依赖和依赖机制促进卵母细胞成熟和发育。
Leptin has been shown to exert positive effects during the maturation of bovine oocytes, influencing blastocyst development, apoptosis, and the transcript levels of developmentally important genes. The present study was conducted to characterize further the mechanisms of leptin action on oocytes and the role of cumulus cells (CCs) in this context. In the first series of experiments, cumulus-oocyte complexes (COCs) were matured in serum-free medium that contained 0, 1 or 10 ng/ml leptin or in medium that was supplemented with 10% (v/v) estrus cow serum (ECS). Leptin concentrations of 1 and 10 ng/ml stimulated the meiotic progression of oocytes. Moreover, TUNEL staining demonstrated that these leptin doses reduced the proportion of apoptotic CCs. In the second series of experiments, COCs or denuded oocytes (DOs) were matured in the presence of 0 or 10 ng/ml leptin. The percentages of COCs and DOs with extruded polar bodies were increased by leptin. In contrast, positive effects of leptin on fertilization rates and blastocyst development were only observed after treatment of COCs but not of DOs. Leptin treatment of COCs consistently enhanced blastocyst development even after parthenogenetic activation of oocytes or after the removal of CCs before fertilization. The proportion of polyspermic oocytes was not affected by leptin treatment or oocyte denudation. In the third series of experiments, COCs were matured in the presence of 0, 1 or 10 ng/ml leptin. The transcript levels of specific genes were determined by reverse transcriptase-quantitative PCR (RT-qPCR) analysis of cumulus cells and single oocytes. Leptin treatment increased the levels of FAS, FASLG, and STAT3 transcripts in oocytes, but did not affect the LEPR, BAX, and BIRC4 mRNA concentrations. In cumulus cells, leptin treatment increased the mRNA levels for LEPR, STAT3, BAX, BIRC4, and FAS, but did not alter FASLG mRNA abundance. In conclusion, leptin differentially regulates gene expression in oocytes and cumulus cells. Moreover, leptin enhances both oocyte maturation and developmental capacity via cumulus cell-independent and -dependent mechanisms.