卵胞浆内单精子注射中小鼠卵细胞第一极体位置和形态对受精率和受精卵质量的影响

目的　探讨卵胞浆内单精子注射 (ICSI)中成熟卵细胞第一极体位置、形态对受精和胚胎质量的影响。　方法　6～ 10周龄雌性小鼠经促超排卵 ,收集成熟卵细胞 ,按第一极体形态不同分三级 ,将同一级别极体随机分 7组 (1、2、3、6、10、11、12点位 )分别行ICSI,观察其受精及卵裂情况。　结果　Ⅰ级极体在 11点位受精率最高 (P =0 .0 0 2 4 ) ,3点位最低 (P =0 .0 0 01) ;I级极体在 11点位产生的高评分原核最多 (P =0 .0 0 0 1) ,3点位最少 (P =0 .0 0 0 1)。Ⅰ级极体的受精率最高、高评分原核最多 ,II级和III级之间无明显差异。　结论　ICSI时卵细胞第一极体位置及形态对正常受精和胚胎质量会产生影响 ,尽可能将第一极体远离固定针、注射针及精子 ,卵细胞的第一极体呈圆形、光滑且完整 ,才能产生高受精率和高质量原核

Effects of the first polar body''''s position and morphology in murine oocyte on fertility rate and fertilized egg quality in intracytoplasmic sperm injection

Objective: To investigate the effects of the position and the morphology of the first polar body in murine oocyte on the fertility rate and fertilized egg quality in intracytoplasmic sperm injection(ICSI). Methods: Mature oocytes were collected from 6～10 wk old female mice by using ovarian hyperstimulation, and divided into three grades according to the morphology of the first polar body. Polar body at same grade was randomly assigned into seven groups (according to the position at 1,2,3,6,10,11,12 o’clock). After ICSI was performed, the results of fertility rate and cleavage of fertilized egg were observed sequentially and compared among groups with different grades and different locations of the first polar body. Results: (1)Compared with the first polar body position at 6,10,12,1 o’clock, the highest and the lowest fertility rates of the first polar body of gradeⅠwere obtained from the 11 o’clock and 3 o’clock( P=0.002 4, P =0.000 1)respectively.(2)Compared with the first polar body position at 6,12,1,10 o’clock, higher score and lower score pronucleus were obtained from the 11 o’clock and 3 o’clock of the first polar body of grade Ⅰ respectively ( P=0.000 1, P =0.000 1). (3)The highest fertility rate and the most high score pronucleus were got from the polar body of gradeⅠ ( P=0 009, P =0.002), and no significant difference was found between grade II and III ( P =0.170, P =0.453). Conclusion: The position and morphology of the first polar body have obvious effects on fertilization and fertilized egg quality in ICSI, and should keep the polar body away from the holding, injection pipetteand sperm. Ideal oocyte having the first polar body with ovoid or round shape, smooth surface can produce higher fertility rate and higher quality pronucleus.