Mechanical isolation and in vitro growth of preantral and small antral human follicles.

OBJECTIVE: To develop a procedure for isolating small human follicles and to determine their growth requirements.
DESIGN: Preantral and early antral follicles were isolated manually, allocated randomly to experimental groups, and cultured for a few weeks.
SETTING: Patients giving informed consent in hospitals. PATIENT(S): Women undergoing laparotomy or oophorectomy. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Follicular size, E2, histology. RESULT(S): Human FSH (at a dose of 1.5 U/mL) induced antral growth of follicles, and the addition of human LH (2.5 ng/mL) to human FSH stimulated growth and antral development. Histologic studies showed that most of the early antral follicles did not contain an oocyte and already had begun to undergo atresia before culturing. Levels of E2 increased in the incubation medium as the follicles increased in size, but those levels were significantly greater when the follicles contained oocytes. CONCLUSION(S): It is possible to grow small human follicles after they have been isolated manually. To develop successfully, they require a low concentration of human LH in addition to human FSH. The rate of atresia between the preantral and early antral stages in vivo is very high; therefore, it is worthwhile to develop techniques for isolating and culturing the follicles before the antral stages.