线粒体基因组D-loop区基因多态性与年龄及IVF-ET结局相关性

Sequence Variation of Mitochondrial DNA D-loop Region are Related with Age and IVF-ET Outcome

目的:研究线粒体基因组D-loop区基因的变异位点与年龄及IVF-ET或ICSI结局的相关性。方法:采用聚合酶链反应(polymerase chain reaction,PCR)和基因片段直接测序方法测定检测167例行IVF-ET或ICSI治疗患者的外周血线粒体基因组D-loop区nt.128～599区域基因变异情况,比较不同年龄组(A组:<35岁,B组:≥35岁)变异位点、年龄及IVF-ET或ICSI结局之间的关系。结果:共有20个变异位点,其中5个为新发现的变异位点。B组的变异位点数(3.8±1.8)显著多于A组的2.6±1.3,其中nt.332C→T在A组发生率显著低于B组(2.2%vs12.2%,P=0.012),且变异位点数量与年龄间存在线性相关,相关系数为0.333。nt.332C→T、nt.249delA和nt.309del/inC三者的变异组年龄显著高于非变异组,nt.309del/inC变异组的累积胚胎平均评分显著低于非变异组(12.9±0.5vs15.5±0.7,P=0.013),nt.249 delA变异组的受精率及累积胚胎平均评分显著低于非变异组(66.86±27.28%vs75.63±21.42%,P=0.046)(12.0±0.7vs14.7±0.5,P=0.013),变异位点数量与受精率及累积胚胎平均评分间存在线性相关。结论:线粒体基因组D-loop区变异位点发生率与年龄相关,且影响IVF-ET/ICSI的受精率及胚胎质量。

Objective：To explore the relationship among age,sequence variations of D-loop region and outcome of IVF-ET.Methods：A total of 167 patients＇ blood samples were collected,who were performed IVF-ET or ICSI.Group A consisted of patients less than 35 years old.Others were assigned into group B.The sequence variations at nt.128-599 of mitochondrial DNA D-loop region were analyzed by using the polymerase chain reaction and direct sequencing.The relationship among D-Loop variations,age and the IVF-ET/ICSI outcome was investigated with t test and χ^2 test.Results：Twenty sequence variations were founded,including 5 novel ones.Group B had more sequence variations than group A（3.8±1.8 vs 2.6±1.3,P〈0.01）.Compared with group A,the C to T at nt.332 happened more frequently in group B（2.2% vs 12.2%,P=0.012）.The transferred embryos mean score of the individuals with variation at nt.249（12.0±0.7） nt.309（12.9±0.5） was lower than the ones without the alteration（14.7±0.5,P=0.013;15.5±0.7,P=0.013）.Moreover,fertilization rate was lower in the individuals with A deletion at nt.249（66.85± 27.28 vs 75.63±21.42,P=0.046）.Individuals with one of the three sequence variations mentioned above were older than the ones without them.In addition,the relationship was linear among the amount of sequence variations,fertility rate,age and embryo quality.Conclusion：Sequence variations in mitochondrial DNA D-loop region are age-related and they will negatively affect the fertilization rate and the oocyte quality.