Eliects Of Microfilaments’ Distribution And Development Potentiality Of Vitrilication To Human Oocytes Matured In Vitro

With the extensive development of assisted reproductive technology, people become to pay more and more attention to oocyte cryopreservation. And oocyte vitrification has become one of the major cryopreservation. How to obtain higher transplantation rates and clinical pregnancy rate has become the focus in many reproductive centers. So freezing damage, especial on ultrastructure, has become the most important study. Many laboratories study the ultrastructure damage of vitrification and it is crucial whether the vitrification oocytes live or not. In recent years, many research centers study the vitrification damage of animal oocytes ultrastructural such as microtubules, spindle structure and developmental potential, cortical granules, mitochondria, cell membrane potential and so on. And the study of human oocytes is relatively small. In view of this, the study was to explore the microfilament ultrastructure of vitrified in vitro maturation oocytes and to analysis contrastively the change of microfilament distribution after vitrification. Then according to different recovery time we analysis the form of microfilament recovery in order to find the proper recovery time. Then in the optimal recovery time, we discussed the oocytes developmental potential after vitrification by intracytoplasmic sperm injection (Intracytoplasmic sperm injection, ICSI). Section1Effect of microfilaments’distribution of vitrification to human in vitro matured oocytes[Objective] To find the appropriate return-time through the contrast analysis of the microfilament structure of vitrification-warmed human in vitro matured oocytes.[Methods] Gathered human in vitro matured oocytes were randomly divided into fresh and vitrified group. The vitrified groups were randomly divided into1h,2h,3h,4h according to different returning time again. Then they were stained by Rhodamine-phalloidine after fixation, permeable membrane, and observed by laser confocal Microscopy (LSM780).[Results] The survival rate was87.37%after vitrification. The normal microfilaments rate of the fresh group was71.11%while the vitrified group was respectively34.15%,44.18%,69.05%,65.07%. There was statistical difference between fresh group and1h,2h(P<0.01, P=0.02) while there was no statistical difference between fresh group and3h,4h(P=1.00, P=0.64). The was no statistical difference between1h and2h as well as between3h and4h(P=0.35, P=0.81).[Conclusions] The vitrification process changes the microfilaments structure of human in vitro mature oocytes. But they can return to the normal state after proper warming. The normal rate of microfilament structure couldn’t increase if continuing to prolong the recovery time. And the proper time is3h at least. Scetion2Effect of development potentiality of vitrification to human in vitro matured oocytes[Objective] To find the change of development potential through the contrast analysis of development potential of vitrification-warmed human in vitro matured oocytes combining with the first part.[Methods] Gathered human in-vitro matured oocytes were randomly divided into fresh and vitrified group. All oocytes were intracytoplasmic sperm injection (ICSI). Then they were observed through the rate of2PN, cleavage, blastocyst, high blastocyst.[Results] The2PN rate, cleavage rate, blastocyst rate, and high quality blastocyst rate of the fresh group were73.08%、23.08%、19.23%、6.73%respectively. And those of vitrification group were respectively55.16%.6.74%、9.00%、2.25%. The number of2PN, high quality embryo and blastocyst were significantly difference between two groups (P=0.01, P<0.01, P=0.04), while the high quality blastocyst wasn’t statistical significance between them(P=0.26).[Conclusions] The vitrification affects the oocytes development potential and it induces the low development potential.