Xiao X, Zi XD, Niu HR, Xiong XR, Zhong JC, Li J, Wang L, Wang Y
Reprod Biol Endocrinol.2014,12:30.
Abstract：BACKGROUND: The competence for embryonic development after IVF is low in the yak, therefore, we investigated the effects of supplementation of FSH, LH and the proteasome inhibitor MG132 in IVM media on yak oocyte competence for development after IVF. METHODS: In Experiment 1, yak cumulus-oocyte complexes (COCs) were in vitro matured (IVM) in TCM-199 with 20% fetal calfserum (FCS), 1 microg/mL estradiol-17beta, and different combinations of LH (50or 100 IU/mL) and FSH (0, 1, 5, 10 microg/mL) at 38.6 degrees C, 5% CO2 in airfor 24 h. Matured oocytes were exposed to frozen-thawed, heparin-capacitatedyak sperm. Presumptive zygotes were cultured in SOF medium containing 6 mg/mlBSA, 0.5 mg/mL myoinositol, 3% (v/v) essential amino acids, 1% nonessential aminoacids and 100 μg/mL L-glutamine (48 h, 38.5 degrees C, 5% CO2, 5% O2, and 90%N2). In Experiment 2, cumulus cells were collected at the end of IVM to determine FSHR and LHR mRNA expression by real-time PCR. In Experiment 3 and 4,COCs were cultured in the presence or absence of the proteasomal inhibitor MG132 from either 0-6 h or 18-24 h after initiation of maturation. RESULTS: The optimum concentration of FSH and LH in IVM media was 5 microg/mL FSH and 50 IU/mL LH which resulted in the greatest cleavage (79.1%) and blastocyst rates (16.1%). Both FSHR and LHR mRNA were detected in yak cumulus cells after IVM. Treatment with MG132 early in maturation reduced (P<0.05) cleavage and blastocyst rates. Conversely,treatment with MG132 late in maturation improved (P<0.05) blastocyst rate.Optimal results with MG132 were achieved at a concentration of 10 microM. CONCLUSIONS: An optimum concentration of FSH and LH in IVM medium, and treatment with MG132 late in maturation can improve yak oocytes competence for development after IVF.