Effect Of Follicle Stimulation Hormone And Pentanoic Acid Estradiol On Mouse Oocyte In Vitro Maturation

Background and ObjectiveIn vitro maturation (IVM) is to conduct a proper condition of in vitro culture to immature eggs so that oocytes reach maturity and have fertilization ability as Mll, while without the application of a small amount of induced ovulation or gonadotropin (Gn). IVM can effectively avoid the application of super-ovulation drugs which may lead to breast, ovarian or other hormone-dependent cancers incidences and potential risk of ovarian hyperstimulation syndrome (OHSS) and other serious complications. It also has obvious advantages such as simplifying treatment, reducing treatment time, decreasing the mental burden of patients and lowering treatment costs. In addition, IVM can be combined with freezing, IVF-ET, ICSI and other technologies in order to pertain reproduction insurance and solve the source of oocytes for premature ovarian failure (POF) patients, and young patients who were operated ovariectomy because of surgery, radiotherapy, chemotherapy and need to preserve the reproductive capacity, as well as other situations of childbearing age women. Moreover, IVM technology can effectively supply oocytes used for basic medical research, and can avoid the ethical disputes. Therefore, IVM could be studied and applied more by scientists all over the world. Although the oocytes can mature and fertilized under in vitro maturation and fertilization system, and can attain the success of pregnancy after fertilized, the maturation, fertilization and pregnancy rates are still low. In recent years, in order to improve the immature oocytes in vitro maturation rate and quality, a large number of scholars have been working on in vitro culture system by adding various substances to improving the microenvironment and thus promote the possibilities of immature oocytes in vitro maturation. Follicle stimulating hormone (FSH) is necessary for follicular growing. In the later phase of the growth of follicular, estradiol and FSH are synergized. Therefore, lots of scholars researched adding follicle stimulating hormone and estradiol to the IVM system to promote the mature of oocytes, but its mechanism and the concentrations are still inconclusive. We researched the effect of Follicle Stimulation Hormone (FSH) and pentanoic acid estradiol on mouse immature oocytes maturation and to examine the capacity of in vitro-matured oocytes underwent in vitro fertilization and merogenesis. Choose the most proper concentration of FSH and pentanoic acid estradiol, and promote the IVM system.Materials and methods1 Research Object:30 female Kuming mice of 8～12 week old and 15 male Kunming mice of 14～18 week old. We use female mice to obtain immature oocytes and use male mice to obtain sperm.2 Research methods:Conducted superovulation on the 8-12 week old female Kuming mice, and killed them after 48 hours by cervical dislocation. Acquired their ovarian and pierced the follicles with 41/2 translucent syringe needle to collect immature oocytes. Immature oocytes were classified as six groups:matured for 24h in the basal culture fluid without hormone and the culture fluid added with 1μg/ml pentanoic acid estradiol, 10μg/ml,100μg/ml pentanoic acid estradiol, and 10IU/mL and 50IU/mL FSH, respectively. The maturation of oocytes in each groups were observed. The matured oocytes were then inseminated in-vitro;and observe the capability of fertilization. Cultivated the inseminated oocytes for another 48～72 hours, and then observed their cleavage. The maturation, fertilization and cleavage percentages were compared byχ2 test.3 Statistic analysis:Statistical analysis used SPSS 13.0 software package. Percentage was used to express results.χ2 test was used to compare rates. Tookα= 0.05 as test standard.Results1. Compared with the groups without hormone, the groups which added with FSH and pentanoic acid estradiol of different concentration had similar percentage of undergoing GVBD, similar percentage of MⅡand similar percentage of cleavage. The differences between them had no statistical significance (P>0.05).2. Fertilization rate in groups which added with 10IU/ml FSH,50IU/ml FSH and 10μl/ml pentanoic acid estradiol, were 42.86%,41.18% and 40%, respectively. These rates were all higher than that in control group(19.44%). The differences between them had statistics significance (P<0.05). Compared with the groups without hormone, the fertilization rate in groups which added with 1μl/ml and 100μl/ml pentanoic acid estradiol had similar percentage of cleavage. The differences between them had no statistical significance (P>0.05).3. The percentage of GVBD, MⅡand cleavage between groups which treated by FSH and pentanoic acid estradiol of different concentrations were similar. The differences between them had no statistical significance (P>0.05).Conclusion1. The addition of 10IU/ml and 50IU/ml FSH in the mouse IVM culture solution could promote the mature of mouse oocyte cytoplasm.2. The addition of 10μg/ml pentanoic acid estradiol in the mouse IVM culture solution could promote the mature of mouse oocyte cytoplasm.