Studies of the leukemia inhibitory factor on preimplantation mouse embryo development

• Main Authors: Tzu-Chun Cheng, 鄭自君
• Other Authors: Jer-Yuh Liu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/55669318267040450092

博士 === 中山醫學大學 === 生物化學研究所 === 92 === Good embryo development and receptive endometrium are essential factors for embryo implantation. Leukemia inhibitory factor (LIF) is an essential factor for implantation and establishment of pregnancy. However, its role in the development of preimplantation embryos remains controversial. The aim of this study is to assess the effects of LIF on development of preimplantation mouse embryo. We observe the relationship between the blastocyst morphology and the implantation rate for mice. Mouse blastocysts were then classified into 3 grades: grade I, small blastocysts; grade II, large blastocysts; grade III, hatching blastocysts. Although there was no significantly different in the implantation rates between the grade III and grade II, grade I was significantly decreased as compared with grade III. Grade I and grade II was also significantly decreased in both the diameter of blastocysts and cell number of inner cell mass (ICM) and trophectoderm (TE) as compared with grade III. These findings indicated that the expanded and haching blastocyst selections for embryo transfer in in vitro culture were evaluated with the high implantation rate. We successfully established the model of in vitro culture and blastocyst transfer for following experiments of LIF. Changes in preimplantation embryos were determined after microinjection of LIF antisense oligonucleotide at the two-pronucleus stage. The 0.5- or 1.0-fmol treated groups had significantly lower percentages of embryos developed to the morula or blastocyst stage and the 2.0-fmol treated group had significantly lower percentages of embryos developed to the four-cell, morula, or blastocyst stage. No embryos developed to the four-cell stage in the 4.0-fmol treated group. Moreover, there was a decreasing trend in the levels of LIF immunoactivity with the increasing amount of LIF antisense oligonucleotide injected. The diameter of blastocysts in the 2.0-fmol treated group was significantly smaller than that in the untreated group. The blastocysts in this group had significantly lower numbers of blastomeres and cells in the ICM or TE and ICM/TE ratio. The 1.0- or 2.0-fmol treated groups had significant lower implantation rates than their corresponding control groups. In the 2.0-fmol groups with supplementing exogenous LIF, significantly lower percentages were also observed in the four-cell, morula, and blastocyst stages. However, blastocysts treated with 50 ng/ml LIF had a significant higher percentage than those in the LIF gene impaired group without LIF supplement. These results indicate that LIF is a critical factor for the normal development of embryos at the preimplantation stages.