Prediction Of Embryo Quality By Measuring Autocrine Insulin-like Growth Factor-Ⅱ (IGF-Ⅱ) In Preimplantation Embryo Culture Fluid

Objective: Recent studies have indicated that insulin-like growth factor- II (IGF- II) increase the growth rate of cultured preimplantation embryos. In the present study we examined whether the amount of autocrine IGF- II in preimplantation embryo culture fluid may be predictable of the embryo quality.Method: 2-cell embryos were cultured to blastocyst stage in four different culture systems:(1)0.3%BSA+ a -MEM simple culture group;(2) coculture with human endometrium epithelial cells in 0.3%BSA+ a -MEM group;(3)P1-BM sequential culture group; and(4)natural development in mouse reproductive tract. Ten 4~8-cell embryos or blastocysts were cultured in the 50ul culture medium microdrops for 4 hours separately,and then the microdrops were stored at -25@ for detecting of IGF- II .In order to perceive the relationship between amounts of IGF- II in microdrops and blastocyst formation and implantation rate,the blastocysts were transferred to day 3 fake pregnant female mice.Results: 1.Comparison of the different culture systems with development of 2-cell embryos: the embryo growth rate and blastocyst formation rate in sequential culture group were significantly higher than coculture group and simple culture group(P<0.05),and coculture group was higher than simple culture group(P<0.05). However, the morphology of embryos had no difference between sequential culture group and coculture group. 2.Comparison of embryo implantation rate:the implantation rate of sequential culture group was lower than in-vivo culture embryos.in spite of it was higher than the other three in-vitro groups. Simple culture group had the lowest implantation rate.3.Embryos cultured in-vivo secrete significantly higher amount ofIGF- II than that of the three in-vitro culture groups at both stage(P<0.05). IGF- II level of sequential culture group is higher than that of coculture group and simple culture group(P<0.05),and the simple culture group was lowest.To all embryos.the amount of IGF- II in blastocyst stage is higher than 4~8-cell stage. 4.Linear regression analysis: set the amount of IGF- II at 4~8-cell stage or blastocyst stage be independent factor X,and blastocyst formation rate and implantation rate be dependentY, we found that the amount of IGF- II at the two stages both have positive correlation with blastocyst formation rate and embryo implantation rate.Conclusions: 1.Sequential culture system can acquire higher blastocyst formation rate and implantation rate,so it may replace coculture system . 2. The amount of autocrine IGF- II may have predictable value to embryo quality and implantaion potential. 3. The Urine is not essential for IGF- II secretion by embryos.