Electroactivation of rabbit oocytes in an hypotonic pulsing medium and parthenogenetic in vitro development without cytochalasin B-diploidizing pretreatment.
We investigated the electroactivation frequencies, type of activation and in vitro development of rabbit oocytes. In Experiment 1, activation (8 pulses, 12 min apart, 60 microsec, 0.6 kVcm(-1)) was performed by altering osmolarity (190 vs. 320 mOsm kg(-1)) and Ca++ concentration (10, 60 or 100 microM) in mannitol pulsing media. More oocytes were activated in hypotonic pulsing medium, regardless of Ca++ concentration (96 to 100%). Both haploid and diploid parthenogenetic embryos developed to compacted morulae (57 to 92% and 63 to 100%, respectively) regardless of the activation treatment; however, the blastocyst rates were more variable (0 to 74% and 0 to 73%, respectively). In Experiment 2, the effects of pulse duration (30 or 60 microsec) and number of applied pulses (4, 8 or 12) under hypotonic conditions were studied. Activation frequencies were the lowest after four 30 microsec-pulses (58 vs. 88 to 100%, respectively). A lower haploid frequency was obtained when more than four 30 or 60 microsec-pulses were applied (from 67 to 25% and 83 to 0%, respectively). Increasing the number of 60-microsec pulses improved the compacted morula rate of haploid and diploid oocytes (47 to 83% and 57 to 96%, respectively). Overall, haploid development to morulae and blastocysts was lower than diploid development to these stages (69 and 25% vs. 74 and 44%, respectively).
Escribá
M J
MJ
Departamento de Ciencia Animal, Universidad Politécnica de Valencia, Spain.
García-Ximénez
F
F
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology* / Q000627:therapeutic use; D004558:Electric Stimulation; D005314:Embryonic and Fetal Development; D005260:Female; D007038:Hypotonic Solutions; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D009994:Osmolar Concentration; D010312:Parthenogenesis / Q000187:drug effects / Q000502:physiology*; D011003:Ploidies; D011817:Rabbits / Q000196:embryology / Q000502:physiology*
D007038:Hypotonic Solutions; D003571:Cytochalasin B; D002118:Calcium