OBJECTIVE: To determine whether the preantral follicles in adult ovaries can generate developmentally competent oocytes after in vitro culture. DESIGN: Prospective, animal-model study. SETTING: Gamete and Stem Cell Biotechnology Laboratory, Seoul National University, Seoul, Korea. ANIMAL(S): B6CBAF1 mice. INTERVENTION(S): Preantral follicles collected from 8-week-old mice were cultured in vitro. MAIN OUTCOME MEASURE(S): Follicle development, embryogenesis, and embryonic stem cell characterization. RESULT(S): A mean of 50.3 preantral follicles were retrieved from one adult animal, which is significantly less than the number (88.7 follicles) retrieved from a prepubertal female. Extension of the culture period greatly improved oocyte maturation; increased follicular growth to the pseudo-antral (89%-91% vs. 32%) or mature oocyte stage (65%-77% vs. 13%) was observed after 12 or 13 days of culture compared with 9 days of culture. Blastocyst formation after parthenogenesis was detected in only one case; in comparison, the use of IVF yielded a large number of embryos that developed into blastocysts. A mean of 14.7 intrafollicular oocytes per animal were produced after 13 days of culture, and 41% of those developed into blastocysts after IVF. Embryonic stem cell-like colonies were established by subculturing the inner cell mass cells from the blastocysts. CONCLUSION(S): Developmentally competent oocytes can be generated by culturing adult preantral follicles. These results may help increase the feasibility of follicle culture systems.
OBJECTIVE: To determine whether the preantral follicles in adult ovaries can generate developmentally competent oocytes after in vitro culture. DESIGN: Prospective, animal-model study. SETTING: Gamete and Stem Cell Biotechnology Laboratory, Seoul National University, Seoul, Korea. ANIMAL(S): B6CBAF1 mice. INTERVENTION(S): Preantral follicles collected from 8-week-old mice were cultured in vitro. MAIN OUTCOME MEASURE(S): Follicle development, embryogenesis, and embryonic stem cell characterization. RESULT(S): A mean of 50.3 preantral follicles were retrieved from one adult animal, which is significantly less than the number (88.7 follicles) retrieved from a prepubertal female. Extension of the culture period greatly improved oocyte maturation; increased follicular growth to the pseudo-antral (89%-91% vs. 32%) or mature oocyte stage (65%-77% vs. 13%) was observed after 12 or 13 days of culture compared with 9 days of culture. Blastocyst formation after parthenogenesis was detected in only one case; in comparison, the use of IVF yielded a large number of embryos that developed into blastocysts. A mean of 14.7 intrafollicular oocytes per animal were produced after 13 days of culture, and 41% of those developed into blastocysts after IVF. Embryonic stem cell-like colonies were established by subculturing the inner cell mass cells from the blastocysts. CONCLUSION(S): Developmentally competent oocytes can be generated by culturing adult preantral follicles. These results may help increase the feasibility of follicle culture systems.