低氧培养对未成熟卵体外成熟及胚胎发育潜能的影响

Developmental competence of human oocytes after in vitro maturation and in vitro culture under low oxygen concentrations

目的:研究辅助生殖技术超促排卵治疗中获得的未成熟卵在低氧培养体系中的发育潜能。方法:卵胞质内单精子显微注射(ICSI)或体外受精-胚胎移植中(IVF-ET)短时受精中挑选出的GV(germinal vesicle)期卵母细胞80枚,MI(metaphase I)期卵母细胞124枚,随机分为实验组和对照组,实验组置于低氧分压(体积分数5%)的三气培养箱中、对照组置于高氧分压(体积分数20%)常规培养箱中进行体外成熟培养(IVM)及随后的囊胚和胚胎培养。IVM后成熟的卵母细胞进行ICSI受精,观察受精率、卵裂率及囊胚形成率。结果:实验组GV期未成熟卵体外培养至MII卵的成熟率、双原核(2PN)率、卵裂率、囊胚形成率及优质囊胚率与对照组无统计学差异(P>0.05)。但实验组MI期卵培养至MII卵的成熟率[96.8%(60/62)]、2PN率[80%(48/60)]、囊胚形成率[43.8%(21/48)]及优质囊胚率[20.8%(10/48)]均高于对照组[分别为58.1%(36/62),52.8%(19/36),11.8%(2/17)和0.0%(0/17)],差异有统计学意义(P<0.05),而2种培养体系的卵裂率无统计学差异。结论:超促排卵中获得的未成熟卵,特别是MI期裸卵在低氧培养体系中进行体外成熟及后续的胚胎培养,有利于获得优质囊胚。

Objective： To investigate the developmental potential of immature oocytes obtained from assisted reproductive technology hyperstimulation ovulation treatment under low oxygen tension culture system. Methods： The oocytes were obtained from intracytoplasmic sperm injection （ICSI） or short-term fertilization, there were 80 oocytes in germinal vesicle （GV） stage and 124 oocytes in metaphase I （MI） stage. All of these immature oocytes were assigned randomly to 5% oxygen tension incubator （experimental group） or 20% oxygen tension of conventional culture incubator （control group） for maturation culture. All the matured metaphase II （MH） oocytes were fertilized by ICSI. The fertilization rate, the cleavage rate and the blastocyst formation rate of the two culture systems were investigated. Results： For the GV oocytes, there was no significant difference in the maturation rate, the 2PN rate, the cleavage rate, the blastocyst formation rate and the good-quality blastocyst rate between the two groups. For the M~ oocytes, there were significantly higher maturation rate, 2PN rate, cleavage rate, blastocyst formation rate and good-quality blastocyst rate in experimental group than the control [96.8% （60/ 62） vs 58.1% （36/62）, 80.0% （48/60） vs 52.8% （19/36）, 43.8% （21/48） vs 11.8% （2/17） and 20.8% （10/48） vs 0.0% （0/17）]. Conclusion： The immature oocytes obtained from super ovulation promoting, especially the MI oocytes can obtain higher maturation rate and more good-quality blastocysts in low oxygen tension culture system.