| Embryo culture is the foundation of embryo engineering technology, and it is valuable for embryo bisection and chimaera, somatic cell nuclear transfer and transgenic animals production. Until now, in vitro culture system can support porcine embryo developing to blastocyst stage but the number and quality of porcine blastocyst in vitro are inferior to blastocyst in vivo. Nowadays in vitro culture system of embryo has not been well established and needs further research to establish a culture system that mimic physiological environment in vivo. There are many factors influencing in vitro culture system, such as water, gas, temperature, culture media, energy substrate, protein additive, osmotic pressure, antioxidant system, and so on.This study examined the effect of medium change and supplemented with fetal bovine serum(FBS), high osmolarity of culture medium and the optimal concentrations of vitamin E on development of porcine embryos derived from in vitro fertilization(IVF)or parthenogenetic activation (PA). Experiment 1: PA or IVF embryos were cultured in PZM-3 for 7days as the control group. The medium change group of embryos were cultured in PZM-3, which was changed to fresh medium on Days 2 and 4. The FBS group of embryos were cultured in the change system up to day 4 and then cultured in PZM-3 supplemented with 10% FBS instead of BSA from Day 4 to 7. Experiment 2: The control group of embryos were cultured in PZM-3 (288 mOsmol) for the whole culture period. Other two groups of embryos were cultured in a modified PZM-3 with 0.05 M sucrose (300–320 mOsmol, sucrose group) or increased NaCl to 138 mM (300–320 mOsmol, NaCl group) for the first 2 days, and then cultured in PZM-3 for the next 5 days. Experiment 3: The control group of embryos were cultured in PZM-3 without vitamin E. Other three groups of embryos were respectively cultured in a modified PZM-3 with 50μM, 100μM, 200μM vitamin E for the whole culture period.In the first experiment, there was no difference in the rate of cleavage among the control group, the medium change group and the FBS group of IVF embryos and PA embryos (P>0.05). The FBS group showed a significantly higher rate of blastocyst compared to the control and the medium change group both of IVF embryos and PA embryos (P<0.05). In experiment 2, IVF embryos cultured in NaCl group showed a significantly higher rate of cleavage and blastocyst compared to the control and sucrose group(86.76% vs 72.46%,73.34%; 20.59% vs 10.87%,11.51%)(P<0.05). In the last experiment , IVF embryos cultured in a modified PZM-3 with 100μM vitamin E(20.16%)showed a significantly higher developmental rate to the blastocyst stage compared to the control (10.08%)(P<0.05), but not significantly higher than that from 50μM group (13.49%) and 200μM group (12.21%)(P>0.05). And the cleavage and blastocyst rate of PA embryos in the last two experiments had no significantly difference between the experiment groups and the control group(P>0.05).These results indicate that only change to fresh medium can not improve the development of IVF and PA embryos, but a change to fresh medium and inclusion of FBS in the medium during the late stages of culture can promote the development on both of IVF and PA embryos. The higher osmolarity(increased NaCl to 138 mM)at the early embryonic stage and the supplementing porcine embryo culture medium with 100μM vitamin E can promote the in vitro development of porcine IVF embryo. But higher osmolarity and vitamin E do not have effect on the development of PA embryos. |
PDF Full Text Request