应用两轮荧光原位杂交进行人类植入前胚胎染色体嵌合型的研究

Analysis of chromosome mosaicism in preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization

目的应用2轮荧光原位杂交技术（fluorescence in situ hybridization,FISH）对人类植入前胚胎染色体嵌合型的发生机制和影响因素进行初步研究。方法选择体外受精与胚胎移植（in vitro fertilization-embryo transplantation,IVF-ET）治疗周期中不适于胚胎移植和冷冻的正常受精胚胎为研究对象,固定后进行2轮FISH,分析13、16、18、21、22、X、Y等7条染色体组成。结果51个胚胎中正常胚胎14个（27.5%）,嵌合型16个（31.4%）,无规律分裂12个（23.5%）,异常非嵌合型9个（17.6%）。5～8细胞期胚胎中嵌合型胚胎的比例显著高于≤4细胞期胚胎（40.0%比12.5%）。非整倍体胚胎的比率在≥35岁组为57.1%,显著高于〈35岁组（23.3%）。结论胚胎染色体嵌合型是植入前胚胎的常见现象,可能是影响IVF成功率的重要因素,而应用2轮FISH技术可有效地进行常见染色体异常的筛查。

Objective To investigate the mechanism and factors affecting mosaicism in human preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization（FISH）. Methods Totally 51 normal fertilized embryos, which were not suitable for embryo transfer and cryopreservation, were analyzed on day 3 after fertilization by using two sequential rounds of FISH. Chromosomes 13, 16, 18, 21, 22, X and Ywere analyzed. Results Among 51 embryos, 16（31.4 % ） were mosaic, 12 （23.5 % ） were chaotic, and the remaining were either normal （27.5 % ） or nonmosaic abnormal（ 17.6% ）. The incidence of mosaic embryos was related to embryo developmental stage, for the incidence of mosaicism increased from12.5% in embryos ≤4 cell stage to 40.0% in 5-8 ceil stage embryos. The aneuploidy rate for the patients over 35 years of age was significantly higher than that of the patients under 35 years （57.1% vs 23.3 % ）. Condusion Mosaieism is common in human preimplantaion embryos, which may be one of the important factors affecting the success rates in IVF-ET. Most of the chromosomal abnormalities can be identified by two sequential rounds of FISH.