Parthenogenetic activation of Chinese hamster oocytes by chemical stimuli and its cytogenetic evaluation

Abstract

This study was undertaken parthenogenetically to activate Chinese hamster oocytes in vitro by chemical stimuli. Oocytes were exposed to five different chemical agents, ethanol (EtOH), strontium chloride (SrCl2), cycloheximide (CHX), phorbol ester (PMA), and ionophore A23187 (IA23). No parthenogenetic activation was observed in the oocytes treated with 8% EtOH for 8–11 min, 1.7 mM and 5.0 mM SrCl2 for 1 hr, 100 μM and 400 μM CHX for 2 hr, and 81 nM and 162 nM PMA for 5 min. In contrast, 89.7% of oocytes parthenogenetically extruded the second polar body in treatment with 3 μM IA23 for 5 min, but only 22.6% of them formed a pronucleus and developed to 2‐cell embryos. The remaining ova stopped their cell cycle immediately after completion of the second meiotic division. They had unichromatid chromosomes (monads), which are called MIII chromosomes. Treatment with 5 μM IA23 for 5 min was so deleterious that >90% of oocytes were degenerated. However, oocyte activation was significantly improved when the treatment with 3 μM IA23 for 5 min was followed by treatment with 8% EtOH for 10 min, 100 μM CHX for 2 hr, 81 nM PMA for 5 min or 3 μM IA23 for 5 min: rates of pronuclear formation were 54.4%, 84.3%, 34.2%, and 54.6%, respectively. More than 80% of pronucleate ova successfully developed into 2‐cell stage. Additive treatment with 5 mM SrCl2 for 1 hr had no positive effect on pronuclear formation. Incidences of aneuploidy (4.6%) and structural chromosome aberrations (1.0%) in parthenogenons produced by combined stimuli of IA23 and CHX were not significantly different from those (3.8% and 1.6%, respectively) in female pronuclei of ova fertilized in vitro, showing that combined treatments with IA23 and CHX cause neither nondisjunction at the second meiotic division nor structural aberrations in MII chromosomes. The present technique for parthenogenetic activation of Chinese hamster oocytes may be useful as an assessment system to detect aneugenic and clastogenic effects of mutagens on mammalian oocytes. Mol. Reprod. Dev. 47:72–78, 1997. © 1997 Wiley‐Liss, Inc.

In vitrodevelopment of goat parthenogenetic and somatic cell nuclear transfer embryos derived from different activation protocols

“…To our knowledge, this is the first report on goat oocyte activation by strontium. Previously, strontium was shown to be inefficient for activation of Chinese hamster (Tateno & Kamiguchi, 1997), bovine (Meo et al ., 2004, 2005, 2007) and porcine oocytes (Che et al ., 2007), although it had been shown to be effective for mouse (O'Neill et al ., 1991; Bos-Mikich et al ., 1995; Kishigami & Wakayama, 2007) and rat oocytes (Krivokharchenko et al ., 2003; Tomashov-Matar et al ., 2005). However, oocyte activation could be improved by a combination of strontium with other chemicals, such as ethanol (Meo et al ., 2004) or ionomycin in cattle (Meo et al ., 2005; Che et al ., 2007) and in pigs (Che et al ., 2007).…”

Activation regimens for full‐term development of rabbit oocytes injected with round spermatids

“…The lower developmental potential of ROSI oocytes into full-term offspring compared to ICSI oocytes may be due in part to suboptimal condition for oocyte activation. Numerous studies have described the chemicals for parthenogenetic activation and subsequent development of rodent oocytes, such as ionophore A23187, ionomycin, puromycin, SrCl 2 , cycloheximide (CHX) and 6-dimethylaminopurine (DMAP) (Ogura et al, 1996;Tateno and Kamiguchi, 1997;Martini et al, 2000;Nakasaka et al, 2000;Hirabayashi et al, 2002b). Except for the CHX (an inhibitor of protein synthesis) and the DMAP (an inhibitor of phosphorylation) that can prevent re-accumulation of the MPF (Fulka et al, 1991;Sz€ oll€ osi et al, 1993), chemicals used in the abovementioned studies induce single or multiple increases of intracellular calcium concentration for triggering the meiosis resumption of oocytes.…”

Parthenogenetic activation and subsequent development of rat oocytes in vitro

“…Parthenogenetic activation of mammalian oocytes can be induced by various stimuli in vitro and in vivo (Kaufman, 1983). There have been a number of studies of parthenogenetic activation and subsequent development in vitro of oocytes in many mammalian species including the mouse (Eusebi and Siracusa, 1983;Onodera and Tsunoda, 1989;Liu et al, 1997;Martini et al, 2000;Nakasaka et al, 2000), rabbit (Onodera and Tsunoda, 1989;Escriba and Garcia-Ximenez, 2000;Yin et al, 2000), hamster (Tateno and Kamiguchi, 1997), pig (Grupen et al, 1999;Jilek et al, 2000;Kurebayashi et al, 2000;Ruddock et al, 2000), cattle (Campbell et al, 2000;Xu and Yang, 2001), and humans . These results indicate that suitable conditions for oocyte activation in vitro vary with animal species.…”