Chmelíková Eva, Jeseta Michal, Sedmíková Markéta, Petr Jaroslav, Tůmová Lenka, Kott Tomás, Lipovová Petra, Jílek Frantisek
Czech University of Life Sciences in Prague, Department of Veterinary Sciences, 165 21 Prague 6 - Suchdol, Czech Republic.
Zygote. 2010 Aug;18(3):235-44. doi: 10.1017/S0967199409990268. Epub 2010 Jan 29.
In this paper we assessed: (i) the change in nitric oxide synthase (NOS) isoforms' expression and intracellular localization and in NOS mRNA in porcine oocytes during meiotic maturation; (ii) the effect of NOS inhibition by N(omega)-nitro-l-arginine methyl ester (l-NAME) and aminoguanidine (AG) on meiotic maturation of cumulus-oocyte complexes (COC) as well as denuded oocytes (DO); and (iii) nitric oxide (NO) formation in COC. All three NOS isoforms (eNOS, iNOS and nNOS) and NOS mRNA (eNOS mRNA, iNOS mRNA and nNOS mRNA) were found in both porcine oocytes and their cumulus cells except for nNOS mRNA, which was not detected in the cumulus cells. NOS isoforms differed in their intracellular localization in the oocyte: while iNOS protein was dispersed in the oocyte cytoplasm, nNOS was localized in the oocyte cytoplasm and in germinal vesicles (GV) and eNOS was present in dots in the cytoplasm, GV and was associated with meiotic spindles. l-NAME inhibitor significantly suppressed metaphase (M)I to MII transition (5.0 mM experimental group: 34.9% MI, control group: 9.5% MI) and at the highest concentration (10.0 mM) also affected GV breakdown (GVBD); in contrast also AG inhibited primarily GVBD. The majority of the oocytes (10.0 mM experimental group: 60.8%, control group: 1.2%) was not able to resume meiosis. AG significantly inhibited GVBD in DO, but l-NAME had no significant effect on the GVBD of these cells. During meiotic maturation, NO is formed in COC and the NO formed by cumulus cells is necessary for the process of GVBD.
在本文中，我们评估了：（i）猪卵母细胞减数分裂成熟过程中一氧化氮合酶（NOS）亚型的表达、细胞内定位及NOS mRNA的变化；（ii）N（ω）-硝基-L-精氨酸甲酯（L-NAME）和氨基胍（AG）抑制NOS对卵丘-卵母细胞复合体（COC）以及裸卵（DO）减数分裂成熟的影响；（iii）COC中一氧化氮（NO）的生成。在猪卵母细胞及其卵丘细胞中均发现了所有三种NOS亚型（内皮型NOS、诱导型NOS和神经型NOS）和NOS mRNA（内皮型NOS mRNA、诱导型NOS mRNA和神经型NOS mRNA），但在卵丘细胞中未检测到神经型NOS mRNA。NOS亚型在卵母细胞中的细胞内定位不同：诱导型NOS蛋白分散在卵母细胞胞质中，神经型NOS定位于卵母细胞胞质和生发泡（GV）中，内皮型NOS存在于胞质、GV中的点状结构中，并与减数分裂纺锤体相关。L-NAME抑制剂显著抑制了中期（M）I向MII的转变（5.0 mM实验组：34.9%为MI期，对照组：9.5%为MI期），在最高浓度（10.0 mM）时还影响了GV破裂（GVBD）；相比之下，AG主要抑制GVBD。大多数卵母细胞（10.0 mM实验组：60.8%，对照组：1.2%）无法恢复减数分裂。AG显著抑制DO中的GVBD，但L-NAME对这些细胞的GVBD没有显著影响。在减数分裂成熟过程中，COC中会生成NO，卵丘细胞生成的NO对于GVBD过程是必需的。
