Harmful or not: Trichostatin A treatment of embryos generated by ICSI or ROSI

Trichostatin A (TSA), a histone deacetylase inhibitor, is a known teratogen causing malformations such as vertebral fusions when applied during the postimplantation period; TSA also causes developmental arrest when applied during the preimplantantion period. Regardless of these hindrances, we have succeeded in the establishment of an efficient somatic method for the mouse where reconstructed embryos are treated with TSA. To elucidate this apparent discrepancy, we treated fertilized mouse embyros generated either by intracytoplasmic sperm injection (ICSI) or round spermatid injection (ROSI) with 50 nM TSA for 20 h after fertilization as well as parthenogenetic embyros and found that TSA treatment inhibited the preimplantation development of ICSI embyros but not ROSI or parthenogenetic embyros. And, although we often observed hypomorphism following TSA treatment in embyros grown to full term produced by both ICSI (av. of body weight: 1.7 g vs. 1.5 g) and ROSI (1.6 g vs. 1.2 g), TSA treatment reduced the offspring production rate for ICSI from 57% to 34% but not for ROSI from 30% to 36%. Thus, these data indicate that the effects, harmful or not, of TSA treatment on embryonic development depend on their procedure in current Assisted Reproductive Technologies.(c) Versita Warsaw and Spring-Verlag Berlin Heidelberg. All rights reserved.