Effects of cycloheximide or 6-dimethyl aminopurine on the parthenogenetic activation of pig oocytes using pulsatile treatment with nitric oxide donor

Abstract

Pig oocytes matured in vitro were parthenogenetically activated using nitric oxide donor SNAP (2mM). Continuous treatment successfully activated the oocytes only after more than 12 hours of exposure. Pulsatile treatments during which oocytes were repeatedly exposed to 2mM SNAP for a short time (10, 20 or 30 minutes) were more efficient with regard to the activation rate, even when the total exposure time did not exceed 4 hours. Parthenogenetic development was very limited after continuous treatment with 2mM SNAP. A significantly higher proportion of developing parthenogenetic embryos was observed after the pulsatile treatment (development to the morula stage 0 vs. 18%; development to the blastocyst 0 vs. 7%; P < 0.05). However, this developmental rate was significantly lower (P < 0.05) than the development induced by conventional activation treatment with calcium ionophore (development to the morula stage, 23%; development to the blastocyst stage, 18%). When we combined pulsatile SNAP-treatment with the effect of protein kinase inhibitor 6-dimethyl aminopurine (6-DMAP) (2mM 6-DMAP for 2 hours) or with the inhibitor of protein synthesis cycloheximide (CHX) (10 µM CHX for 2 hours), we observed a significant increase (P < 0.05) in the activation rate when compared to the respective pulsatile SNAP-treatment without 6-DMAP or CHX (63 vs. 78% of activated oocytes for 6-DMAP; 63 vs. 83% of activated oocytes for CHX). However, the development of parthenogenetic embryos was not enhanced when the pulsatile SNAP-treatment was combined with 6-DMAP or with CHX.

The optimal period of Ca-EDTA treatment for parthenogenetic activation of porcine oocytes during maturation culture

“…In this study, Ca-EDTA treatment during maturation culture not only activated porcine immature oocytes but also induced parthenogenetic development to blastocyst stage. It had been shown that MII-stage oocytes can be parthenogenetically activated by artificial stimuli and that activated oocytes can cleave and develop to the blastocyst stage [ 12 , 13 ]. Historically, Azuma et al .…”

The role of nitric oxide synthase isoforms in aged porcine oocytes

“…Moreover, NOS inhibition supresses cumulus expansion of sheep oocytes . The role of NO in oocyte activation and early embryonic development of fertilized or parthenogenetically activated oocytes was also studied (Goud et al, 2008;Krejčová et al, 2009). Although not essential for mouse oocyte fertilization (Hyslop et al, 2001), NO is able to activate the oocytes of pigs and amphibians (Petr et al, 2005Jeseta et al, 2012), presumably throughout cGMP and PKG signalling pathways (Petr et al, 2006).…”