BENEFICIAL-EFFECTS OF ELECTRICAL-STIMULATION BEFORE ROUND SPERMATID NUCLEI INJECTIONS INTO RABBIT OOCYTES ON FERTILIZATION AND SUBSEQUENT EMBRYONIC-DEVELOPMENT

Objective: To evaluate the effects of electrical stimulation of rabbit oocytes before round spermatid nuclear injection procedure on oocyte activation and fertilization. Design: The ratio of activated oocytes t o the number of successfully injected oocytes and the proportion of of fspring to the number of activated oocytes after round spermatid nucle ar injections into oocytes stimulated via mechanical stimulation (grou p A) or a combination of electrical and mechanical stimulation (group B) was compared. Interventions: Round spermatid nuclei were isolated f rom mature male rabbits and microinjected into the oocytes of groups A and B. Injected oocytes were cultured for 24 hours. The embryos devel oped from groups A and B were transferred to synchronized recipient do es. Results: Embryos that developed normally through implantation in g roups A and B were carried successfully through complete gestation in the recipient does. The ratio of the activated oocytes to the number o f successfully injected oocytes and the proportion of offspring to the number of activated oocytes were significantly higher in group B. Con clusion: Electrical stimulation of oocytes before ooplasmic spermatid nuclear injections and ET procedures has beneficial effects on oocyte activation, fertilization, and subsequent embryonic development.