Manser R C, Leese H J, Houghton F D
Department of Biology (Area 3), University of York, PO Box 373, York YO10 5YW, United Kingdom.
Biol Reprod. 2004 Aug;71(2):528-33. doi: 10.1095/biolreprod.103.025742. Epub 2004 Apr 7.
Nitric oxide (NO) is a free radical that functions as a cell signaling molecule but at high concentrations can be toxic. It is formed from arginine, which is consumed by the mouse blastocyst, but its effect on early embryo development has been little studied. In this study, the role of NO in mouse preimplantation development has been examined in terms of developmental rate and oxidative metabolism. Zygotes were cultured in one of four media; potassium simplex optimization medium (KSOM), KSOM with amino acids (KSOMaa), KSOM without glutamine (KSOM-glut), or KSOM with 0.5 mM arginine (KSOMarg) +/- l-NAME (a specific inhibitor of NO production). End points were Day 4 blastocyst rates, cell counts determined using bisbenzimide and oxygen consumption. In KSOM and KSOM-glut, the blastocyst rate was decreased by 1 mM l-NAME from 50.2% +/- 3.1% and 37.4% +/- 4.5% to 6% +/- 3% and 0%, respectively. In KSOMaa, cavitation rates were unaltered but the blastocysts contained fewer cells (P < 0.001). Blastocysts cultured in KSOM and KSOM-glut consumed significantly more oxygen than those cultured in KSOMaa (P < 0.001 and P < 0.05, respectively). However, the addition of 0.1 mM or 1 mM l-NAME to KSOMaa significantly increased the amount of oxygen consumed (P < 0.05 and P < 0.001, respectively). The data suggest a physiological role for NO in mouse preimplantation metabolism and development. One possibility is that NO may limit oxygen consumption at the blastocyst stage at the level of mitochondrial cytochrome c oxidase.
一氧化氮（NO）是一种自由基，作为细胞信号分子发挥作用，但在高浓度时可能具有毒性。它由精氨酸生成，而精氨酸会被小鼠囊胚消耗，但其对早期胚胎发育的影响鲜有研究。在本研究中，从发育速率和氧化代谢方面考察了NO在小鼠植入前发育中的作用。合子在四种培养基之一中培养：钾离子简单优化培养基（KSOM）、含氨基酸的KSOM（KSOMaa）、不含谷氨酰胺的KSOM（KSOM - glut）或含0.5 mM精氨酸的KSOM（KSOMarg）±L - NAME（NO生成的特异性抑制剂）。终点指标为第4天的囊胚率、使用双苯甲酰亚胺测定的细胞计数以及氧气消耗。在KSOM和KSOM - glut中，1 mM L - NAME使囊胚率分别从50.2%±3.1%和37.4%±4.5%降至6%±3%和0%。在KSOMaa中，囊泡形成率未改变，但囊胚中的细胞数量较少（P < 0.001）。在KSOM和KSOM - glut中培养的囊胚比在KSOMaa中培养的囊胚消耗的氧气显著更多（分别为P < 0.001和P < 0.05）。然而，向KSOMaa中添加0.1 mM或1 mM L - NAME显著增加了氧气消耗量（分别为P < 0.05和P < 0.001）。数据表明NO在小鼠植入前代谢和发育中具有生理作用。一种可能性是NO可能在线粒体细胞色素c氧化酶水平限制囊胚阶段的氧气消耗。
