Study On The Immature Human Oocytes From Icsi Cycles In Vitro Maturation And Embryonic Developmental Competence

Objective:To explore the subsequent embryo development in vitro of human immature oocytes from ICSI cycles and assess the reusing value of the immature oocytes from the controlled ovarian hyperstimulation cycles.Methods:A total of 405 morphologically normal immature oocytes were recruited from 144 consecutive infertile women in ovarian stimulation cycles for the first ICSI cycle in Reproductive Medicine Research Center of the Third Affiliated Hospital of Guangxi Medical University and GnRH-a long stimulate ovulation was adopted.The collected oocytes were randomized divided into three groups:A group is IVM medium(control group) collected 89 oocytes; B group is L-carnitine supplementation to IVM medium(drug group) collected 97 oocytes;C group is IVM medium co-culture with granulosa cells(co-culture group) collected 219 oocytes.Rate of maturation egg between the three groups for different time periods were calculated and the C group was choosed as the best IVM medium.The metaphase MⅡ stage oocytes from co-culture group were cultured after intracytoplasmic sperm injection,and divided into MⅠ stage and GV stage group (CⅠ group VS CⅡ group),fresh and frozen group(C1 group VS C2 group),MI-24h maturation and MI-48h maturation group (CⅠa group VS Clb group).The rates of fertilization and cleavage and early embryonic development were compared in different groups.Results:1. The maturation rate in 24h of MⅠ stage oocytes from C group was higher than A and B group,the difference was statistically significant(67.4 VS 24.6%,30.8%). Compared the rate of maturation in 48h, B and C group were all higher than A group with statistically significant (88.9%,87.2% VS 73.8%).There was not statistically different for GV stage oocytes among the groups.2. Compared with GV stage oocytes, the MⅠ stage oocytes from co-culture group in vitro maturation to MⅡ stage received high survival rate.The difference was statistically significant(P<0.05).3. In co-culture group,compared with the fresh group and the frozen group,there was no significant difference between the rates of fertilization, abnormal fertilization,the high-quality embryo and blastocyst formation(P> 0.05).The rate of fresh group of cleavage was higher than frozen group had significant difference (P<0.01).4. In co-culture group,compared with the MⅠ stage group and GV stage group,there was no statistically difference between the rates of fertilization, cleavage, high-quality embryo and blastocyst formation(P> 0.05).GV stage oocytes in co-culture group in vitro maturation did not formed blastocystThe MI stage group obtained 10.0%(5/50) blastocyst formation rate.5. In co-culture group,the rates of 24h maturation group of fertilization and cleavage were hihger than 48h group to the MI stage oocytes,and the cleavage rate was significantly different (P<0.01).The MⅠ stage oocytes co-cultured 48h did not get high-quality embryo and blastocyst. The 24h maturation group obtained 28.6%(14/49) high-quality embryo rate and 10.2%(5/49) blastocyst formation rate.6. Compared with sibling in vivo matured oocytes,the rates of fertilization, embryo cleavage, high-quality and blastocyst formation were significantly lower in IVM group. However, the abnormal fertilization rate was no statistically difference between two groups.Conclusion:1. Maturation in vitro can be accomplished in human’s COH-ICSI cycles.The immature oocytes and granulosa cells co-cultured in vitro maturation could get better results.2. The MⅡ stage oocytes matured in co-culture group from MⅠ stage were more resistant to freezing process of vitrification than GV stage.3. Vitrification may diminishes the cleavage of MⅡ stage oocytes in vitro maturation.