Abstract
In order to evaluate the physiological events in early stage of human embryos after intracytoplasmic sperm injection (ICSI), we have developed new embryo culture system on the stage of inverted microscope as a time-lapse cinematography. Time-lapse recording (Exposure time: 50 ms; Interval: 2 mins) commenced shortly after ICSI and continued up to 40 h. We examined a total of 65 oocytes obtained from 62 patients with ICSI. Fifty five (84.6%) of 65 oocytes showed 2PN/2PB fertilization and all of which cleaved. Out of 55 embryos cleaved, 42 (76.4%) developed into morphologically good quality embryos (GQE), while remaining 13 embryos were classified as poor quality embryos (PQE). There was no significant difference in the time course required for physiological events during early stage of embryos between GQE and PQE. Although no significant difference was observed in the pattern of nucleolar precursor body (NPB) distribution between GQE and PQE, the appearance of cytoplasmic halo during 2PN stage of embryos was significantly related to embryo quality (p<0.05). This study indicates that cytoplasmic halo is a new parameter in the evaluation of good quality embryo. Furthermore, time-lapse cinematography is an excellent tool in elucidating the physiological phenomenon in the early stage of human embryos.
