Parthenogenetic activation of rat oocytes and their development (in vitro)

Abstract

The present study was performed to determine suitable methods for parthenogenetic activation and subsequent development of rat oocytes in vitro. In the first series of experiments, the ability of electrical pulses, strontium, ethanol and ionomycin to activate Sprague-Dawley (SD) rat oocytes was examined. The synergistic effect of strontium and cycloheximide or puromycin was also examined in the second series of experiments. In the third series of experiments, the development of F1 hybrid (SD x Dark Agouti) parthenotes activated with different concentrations of strontium (10-0.08 mM) was compared with that of SD parthenotes. The effect of the timing of activation (10 min and 2, 4 and 6 h after cervical dislocation) was also assessed in a fourth series of experiments. The oocytes activated by strontium showed higher pronuclear formation and cleavage rates than those in the other groups (P < 0.05). Higher blastocyst development was obtained from parthenotes activated by strontium and strontium-cycloheximide compared with the strontium-puromycin group (P < 0.01). However, the total cell number of blastocysts from the strontium-cycloheximide activation group was higher than that of other groups (P < 0.05). With strontium (2.5-10 mM) treatment, 40.9% of blastocysts were obtained from F1 hybrid oocytes, whereas 22.9% were obtained from SD (P < 0.01). The oocytes activated 10 min or 2 h following cervical dislocation showed higher blastocyst development than those of the 4 and 6 h groups (P < 0.01). These results suggest that strontium-cycloheximide produces the highest parthenogenetic activation rate in the rat and that oocytes must be activated by 2 h after cervical dislocation.

Human parthenogenetic blastocysts derived from noninseminated cryopreserved human oocytes

“…To date, parthenogenetic activation of oocytes was performed in most mammals, including mice, goats, cows, monkeys, and human beings (12)(13)(14)(15)(25)(26)(27)(28)(29)(30)(31)(32)(33).…”

“…One of the alternative protocols proposed is parthenogenesis, in which embryonic development is initiated without sperm contribution. Parthenogenetic activation mainly was studied in experimental species (12)(13)(14).…”

Determination of Optimal Conditions for Parthenogenetic Activation and Subsequent Development of Rat Oocytes In Vitro

“…This specific characteristic may affect the results of the activation treatment in vitro. A recent study indicated that SD rat oocytes ac tiv ated 10 m in or 2 h follo w ing cer vi cal dislocation showed higher blastocyst development than those of the 4 and 6 h groups [22]. Our results using WI rat oocytes in the present study show that although there was no difference in the percentages of activated oocytes with pronuclei, the ability to d e v e l o p t o t h e b l a s t oc y s t s t a g e d e c l i n e d significantly as the culture duration before activation was increased.…”

“…Oocytes from WI rats were collected 16,18,20,22,24 or 26 h after hCG injection and subjected to parthenogenetic activation by electrical stimulation in combination with 6-DMAP as described above. Activated oocytes were transferred to fertilization medium and c ultur ed for 22-24 h. T hey wer e then transferred to mR1ECM drops and culture was continued.…”

Production of Transgenic Rats

“…A strontium protocol was adapted from mouse studies and most frequently used. However, we and others (Hayes et al, 2001;Roh et al, 2003) observed embryolysis in Ca 21 free medium and in 10 mM Sr 21 . Subsequent optimizations included decreasing Sr 21 concentration to 5 mM Sr 21 or supplementing of activation medium with 1.7 mM calcium (Mizumoto et al, 2008).…”