Heterotopic ovarian transplantation without vascular pedicle in syngeneic Lewis rats: long-term evaluation of effects on ovarian structure and function

OBJECTIVE: To assess the long-term efficacy of intraperitoneal (IP) and subcutaneous (SC) ovarian autotransplantation in rats. DESIGN: Experimental animal study. SETTING: Unit of Experimental Research, Barcelona University School of Medicine. ANIMAL(S): Female syngeneic Lewis rats aged 14 weeks. INTERVENTION(S): Group A, control group undergoing ovariectomy (n = 15); group B, undergoing ovariectomy and IP autologous heterotopic transplant (n = 15); and group C, ovariectomized with SC autologous heterotopic transplant (n = 15). In groups B and C, five animals were killed and their ovaries removed for morphometric analysis at 30 days after transplantation; five additional animals were killed at 180 days, and the remaining five animals were killed at 360 days. MAIN OUTCOME MEASURE(S): Ovarian morphometric analysis and serial measurement of E(2) and FSH serum levels. RESULT(S); The mean number of antral follicles in the control group A was significantly higher than that observed in the ovarian grafts collected and examined 30 days after grafting in rats from groups B and C, but the mean granulosa cell area was significantly higher in both transplantation groups than in controls because of ovarian follicular hyperplasia. Histological examination of ovaries removed at 6 and 12 months after grafting in groups B and C showed increasing degrees of fibrosis, loss of primordial follicles, and the presence of epithelial cysts. In groups B and C, from day 30 after surgery onward, serum E(2) was significantly higher and FSH significantly lower, respectively, than in group A. E(2) and FSH patterns in groups B and C were similar throughout the study period. CONCLUSION(S): Heterotopic ovarian transplantation without vascular pedicle in rats is characterized by follicular hyperplasia endocrinologically functional, followed by progressive loss of follicles in heterotopic ovarian autografts.