Valproic acid improves the in vitro development competence of bovine somatic cell nuclear transfer embryos

The present study was carried out to examine the effect of valproic acid (VPA), an important histone deacetylase inhibitor, on the in vitro development and expression of the epigenetic marker histone H3 lysine 9 (H3K9ac) in bovine somatic cell nuclear transfer (SCNT) embryos. We found that treatment with 4 mM VPA for 24 h could significantly improve the development of bovine SCNT embryos. Compared with the no-treatment group, the cleavage rate was higher (69.79 ± 0.99% vs. 65.11 ± 1.02%, p<0.05), as was the blastocyst rate (39.99 ± 1.29% vs. 34.87 ± 1.74%, p<0.05). Moreover, the rate of apoptosis (1.91 ± 0.48% vs. 5.67 ± 0.40%, p<0.05) in blastocysts was greatly reduced after VPA treatment. Valproic acid treatment also increased the immunofluorescent signal for H3K9ac in SCNT embryos in a pattern similar to that of in vitro fertilized (IVF) embryos. In conclusion, we demonstrated that VPA can significantly improve the in vitro developmental competence and enhance the nuclear reprogramming of bovine SCNT embryos.