Distribution and epidermal growth factor receptor expression of primordialfollicles in human ovarian tissue before and after cryopreservation

The freezing of ovarian tissue and the growth of immature oocytes from prim ordial follicles is an interesting concept in ovarian tissue transplantatio n and in-vitro fertilization. In this study, the morphology and distributio n of primordial follicles were studied in ovarian tissue from 24 women befo re and after cryopreservation, Cryopreservation did not significantly chang e either the morphology or number per unit volume of morphologically normal follicles in frozen ovarian tissue. Primordial follicles were predominant, accounting for 78.6% and 82.6% of total follicles in fresh and frozen ovar ian tissues respectively. The distribution of follicles was extremely uneve n in ovarian tissue. A large variation in follicle numbers was observed in ovarian tissue samples from patient to patient, and even in the same patien t. indicating that the number of follicles counted in one sample of ovarian tissue may not represent the number of follicles in other tissue samples. Ovarian tissue could be frozen in the form of strips instead of fragments f or fast processing and better viability of ovarian tissue in cryopreservati on, The number of follicles in ovarian tissue declined with the increasing age of the patients. An immunohistochemical study showed that immunoreactiv ity for the epidermal growth factor (EGF) receptor was detected in primordi al follicles of adult ovarian tissue. EGF receptor staining was most intens e in the oocytes of primordial follicles. Weak staining for EGF receptor wa s observed in some surrounding pregranulosa cells. Immunohistochemical stai ning for EGF receptor was also present in the stromal cells of ovarian tiss ue, but to a much lesser degree. There was no significant difference in the immunohistochemical staining for EGF receptor in ovarian tissue before and after cryopreservation.