Effect of histone deacetylase inhibitor (Trichostatin A ) on preimplantation development of clonded porcine embryos

Abstract

Until now, the successful cloning of porcine by somatic cell nuclear transfer (SCNT) has remained low. The effort of using Trichostatin A (TSA), a potent histone deacetylase inhibitor (HDACi) to improve the efficiency of cloning has demonstrated positive role on cloned embryos development in various species but the underlying mechanism is still unclear. According to the previous researches, the effect of TSA only lead to the hyperacetylation for a short period after treatment, hence a new approach to induce the level of histone acetylation was to treat TSA for futher culture. The objective of this study was to examine the 2-step TSA treatment for SCNT porcine embryos and investigate acetylation level of histone on developmental competence of cloned embryos. In the first experiment, we examined the effect of TSA treatment with various timing (0h, 5h, 10h) on developmental competence of SCNT porcine embryos. In the second experiment, effect of TSA treatment with different concentration (0, 10nM, 25nM) at 0 h and 58 h after activation (hpa) for 5 hpa and 6 hpa respectively were examined. The results shown that treatment with 10nM TSA for 5 hpa, then for 6h at 58 hpa resulted in the increase of blastocyst formation rate (50%) and mean cell number (50,83 ± 2,33) as compared with the non-treated group (0h) (30.6% and 44,33 ± 2,56, respectively). We then investigated the level of histone acetylation H3 lysine 9 in cloned embryos treated with or without TSA [TSA (+) or TSA (-)] at the pro-nuclear, 2-cell, 4-cell, morula and blastocyst stage. The acetylation level of TSA (-) embryos in pro-nuclear stage were significantly lower than TSA (+) embryos. There was no considerable difference in acetylation level of TSA (+) compared to TSA (-) from 2-cell to blastocyst stage. Our data therefore suggested that the 2-step treament of 10 nM TSA for 5 h after SCNT in porcine embryos can improve considerably the preimplantation development in SCNT porcine embryos. Keywords: Trichostatin A; Somatic cell nuclear transfer; Porcine cloned embryos; Histone acetylation; Preimplantation development.