Lanosterol 14α-demethylase expression in the mouse ovary and its participation in cumulus-enclosed oocyte spontaneous meiotic maturation in vitro
Lanosterol 14α-demethylase expression in the mouse ovary and its participation in cumulus-enclosed oocyte spontaneous meiotic maturation in vitro
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小鼠卵巢中羊毛甾醇 14α-去甲基酶的表达及其参与体外卵丘封闭卵母细胞自发减数分裂成熟。
DOI：
10.1016/j.theriogenology.2006.01.065
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发表时间：
2006-09-15
期刊：
影响因子：
2.8
通讯作者：
Xia, Guoliang
中科院分区：
文献类型：
--
作者：
Wang, Chao;Xie, Huirong;Xia, Guoliang
观察了小鼠卵巢给予促性腺激素后，羊毛甾醇14α-脱甲基酶(LDM)的表达，并观察了由LDM作用产生的卵泡液减数分裂激活甾醇(FF-MAS)对卵丘细胞封闭卵母细胞(CEO)卵母细胞自发成熟的影响。在给予促性腺激素前，LDM主要在原始卵泡和次级卵泡的卵母细胞中表达，而在给予马绒毛膜促性腺激素后48h，在卵巢体细胞中有明显的表达，尤其是在给药后54h和48h后，在黄体细胞和卵丘细胞中表达更明显。较大卵泡经心电处理后，卵母细胞LDM的表达仅略有升高。反之，hCG处理48h后，LDM仅在间质细胞中表达增强。因此，心电可能是LDM表达的主要促性腺激素，进而是小鼠卵丘细胞产生FF-MAS的主要促性腺激素，而卵丘细胞是卵母细胞体内成熟所必需的。反之，40 mU M-杜鹃素或50 mU M RS-21745均能显著抑制卵母细胞体外培养4h后的生发泡破裂，生发泡破损率分别降至14%和20%，而自然成熟时分别为90%。用DELTA 14-还原酶和DELTA 7-还原酶的特异性抑制剂AY9944-A-7(5~100mU)处理后，卵母细胞出现明显变性(50mU)时，CEO的GVB无明显增加。这种现象可能归因于AY9944-A-7对FF-MAS的缓慢、被动积累，而不是与快速的自发进展有关。此外，在自发成熟的CEO中，LDM优先在卵丘细胞而不是卵母细胞中表达。因此，FF-MAS可能对CEO的自发成熟有积极的作用。综上所述，体内发育卵泡中的卵母细胞和体细胞均存在心电依赖性的双重LDM表达模式，这可能是卵母细胞成熟过程中卵丘细胞LDM表达增加和FF-MAS产生增加的原因之一。首次发现LDM抑制剂对自发成熟的CEO有抑制作用，并在自发成熟的CEO中有较强的LDM表达，提示卵丘细胞产生的FF-MAS可能参与了小鼠CEO的自发成熟。(C)2006 Elsevier Inc.保留所有权利。
The expression of lanosterol 14 alpha-demethylase(LDM) in the mouse ovary after gonadotrophin administration was examined and the action of follicle fluid meiosis activating sterol (FF-MAS), derived from lanosterol by the action of LDM, on oocyte spontaneous maturation was also evaluated in cumulus cell enclosed oocytes (CEOs). Expression of LDM was primarily in oocytes in primordial and secondary follicles prior to administration of gonadotrophins, but obvious LDM expression was apparent in ovarian somatic cells 48 h after administration of equine chorionic gonadotrophin (eCG), especially in luteal and cumulus cells 54 h after eCG or 48 h after eCG plus 6 h after human chorionic gonadotrophin (hCG). The LDM expression in oocytes was only slightly elevated in larger growing follicles after eCG treatment. On the contrary, 48 h after hCG treatment, the elevated expression of LDM was only detected in interstitial cells. Therefore, eCG may be the primary gonadotrophin for LDM expression, and furthermore for production of FF-MAS in mouse cumulus cells (which are indispensable for oocyte maturation in vivo). Conversely, inhibitors of LDM, either 40 mu M azalanstat or 50 mu M RS-21745, significantly inhibited oocyte germinal vesicle breakdown (GVB) after 4 h of in vitro culture; GVB rates decreased to 14 or 20%, compared to 90% in spontaneous maturation, respectively. There was no significant increase in GVB in CEOs following specific inhibitor of sterol Delta 14-reductase and Delta 7-reductase, AY9944-A-7 (5-100 mu M), until marked oocytes degeneration appeared (50 mu M). The phenomena may be ascribed to slow, passive accumulation of FF-MAS by AY9944-A-7, which cannot be associated with fast spontaneous progression. Furthermore, in spontaneous-matured CEOs, LDM was expressed preferentially in cumulus cells instead of oocytes. Therefore, FF-MAS may have a positive role in the spontaneous maturation of CEOs. In conclusion, there was an eCG-dependent dual LDM expression pattern on both oocytes and somatic cells in growing follicles in vivo, which may increase LDM expression and FF-MAS production in cumulus cells for oocyte maturation. For the first time, the inhibitory effect of LDM inhibitors on spontaneous maturation, together with the strong LDM expression in spontaneous matured CEOs, indicated that FF-MAS produced by cumulus cells might participate in spontaneous maturation of mouse CEOs. (c) 2006 Elsevier Inc. All rights reserved.