【作者】 张璐；

【导师】 薛立群； 刘杨；

【作者基本信息】 湖南农业大学 ， 动物遗传育种与繁殖， 2005， 硕士

【摘要】 一氧化氮(nitric oxide,NO)是一种具有自由基性质的生物活性分子,作为一种信号分子,NO在机体防御、神经信号传导、血管扩张等生理过程中发挥着重要的作用。生物体内的一氧化氮由一氧化氮合酶(NOS)催化L-精氨酸脱胍基产生L-胍氨酸而成,现已确认的一氧化氮合酶有3种亚型,分别是神经元型NOS(nNOS)、内皮型NOS(eNOS)和诱导型NOS(iNOS)。NOS是一氧化氮生成过成中的限速酶,因此某一组织中NOS的量能线性反应出该组织中NO的量。 NO作为一种多功能的分子,在许多生理系统的信号传递中起重要作用,近年来有许多研究表明NO在体内外早期胚胎发育中具有重要的调节作用。动物早期胚胎的发育是个体发育的重要阶段,其发育过程受体内许多因素的调节和影响。人们已从多个方面对早期胚胎发育过程作了大量的研究,然而对NO在早期胚胎中可能产生的生理调节作用了解较少。为了探讨NO对小鼠早期胚胎发育的影响,深入研究早期胚胎发育机制,揭示其发育过程的调节规律,本研究采用反转录聚合酶链式反应(reverse transcription-polymerase RT-PCR)方法检测了附植前各发育时期胚胎中nNOS、iNOS和eNOS的mRNA的表达情况。结果表明:1-细胞胚胎到早期囊胚均有nNOS和eNOS mRNA的表达,1-细胞期到桑椹胚的相对表达量有上升趋势,到早期囊胚又有所下降,经t检验各期胚胎nNOS和eNOSmRNA的相对表达量差异不显著(P>0.05)。除了早期囊胚,其它各期的早期胚胎均有iNOS mRNA的表达,且相对表达量有所增加,到桑椹胚时相对表达量最大,经t检验,1-细胞胚胎到8-细胞胚胎的iNOS mRNA的相对表达量差异不显著(P>0.05),而桑椹胚和其它各期胚胎的iNOS mRNA的相对表达量差异显著(P<0.05)。 结果表明,小鼠早期胚胎的发育至少需要两种NOS的参与,NO在小鼠早期胚胎的正常发育过程中起着重要的调节作用,并可能与附植前胚胎的信号传递及早期分化有关。更多还原

【Abstract】 Nitric oxide (NO) is a free radical molecule which has biological activity. As a signaling molecule, it plays an important role in many physiological processes, such as host defence mechanisms, neuronal signal transmission and vasodilation. NO is produced when the nitric oxide synthase (NOS) catalyzes the oxidation of L-arginine to L-citrulline. Various isoforms of NOS have been identified and include neuronal nitric oxide synthase (nNOS), inflammatory or macrophage nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS). The amount of NOS in some tissue can respond linearly the amount of NO in this tissue because NOS is the rate-limiting enzyme of in the process of generating NO.In recent years, many studies demonstrate that NO production plays an important role in regulating preimplantation embryo development both in vivo and in vitro. Early embryo development is a key stage and is regulated by many factors, including NO, but the regulating mechanisms of NO during early embryo development are not clear now. In order to Probe into effects of NO on early embryonic development deeply, the activity of nNOS , eNOS and iNOS mRNA in the early embryonic development of the mice was examined by the RT-PCR . mRNA of nNOS and eNOS was amplified from 1-cell to preblastula stage embryos and the level of expression gradually increased. T test showed that the expression not significantly (P>0. 05). mRNA of iNOS was only amplified from 1-cell to morula stage embryos and the level of expression gradually increased. The expressive level of preblastula stage embryos is the most. T test showed that the expression of iNOS mRNA from 1-cell to 8-cell stage embryos is not significant (P>0. 05) , but the expression of iNOS mRNA in morula stage embryos is significant (P<0. 05).These results confirm that the preimplantation embryo evelopment of mice need tow type NOS at least . NO plays an important role in regulating early embryos development in mice. And it also relate to signal transmiting and promoting differentiation of early embryo.更多还原