Expression Of NNOS,iNOS And ENOS MRNA In Mouse Early Embryo

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.