224. Platelet derived growth factors and receptors in the rat ovary contribute towards preantral follicle growth
L. S. Sleer A and C. C. Taylor ADeptartment of Cell Biology, Georgetown University Medical Center, Washington, DC, USA
Reproduction, Fertility and Development 17(9) 87-87 https://doi.org/10.1071/SRB05Abs224
Submitted: 26 July 2005 Accepted: 26 July 2005 Published: 5 September 2005
Abstract
In this study, the family of platelet derived growth factors (PDGF) and receptors were identified and characterized in the rat ovary and a role in contributing towards growth of preantral follicles was revealed. Real-time polymerase chain reaction revealed the presence of mRNA for all platelet derived growth factors (PDGF-A, PDGF-B, PDGF-C and PDGF-D) and receptors (PDGF-Rα and PDGF-Rβ). In situ hybridization identified oocytes of primordial/primary follicles and cells of the theca layer as a source of PDGF-B, PDGF-C and PDGF-D mRNA. Protein expression was explored through immunohistochemistry. In rats aged days 0 and 4, PDGF-Rα, PDGF-A and PDGF-C immunoreactivity was observed within oocyte clusters, and PDGF-Rβ and PDGF-B immunoreactivity in cells surrounding oocyte clusters. In primordial follicles, PDGF-Rβ and PDGF-C was observed in the oocyte, and PDGF-Rα and A in the either the oocyte or pregranulosa cells. In primary follicles, PDGF-A, PDGF-C, PDGF-Rα and PDGF-Rβ are expressed in the oocyte. PDGF-Rβ is also expressed in cells surrounding primordial and primary follicles, possibly the precursors to theca cells. In secondary and antral follicles, all four PDGF isoforms and both receptors are expressed in either theca or vascular cells of the theca layer, and PDGF-Rα and A are also expressed in some granulosa cells in rats aged day 20 and older. A role in preantral follicle growth was identified by in vitro culture of preantral follicles. Preantral follicles cultured in serum free medium increased in diameter by 11.0 ± 1.57% over 5 days. Addition of PDGF-AA, PDGF-AB or PDGF-BB to the medium resulted in increases in follicle diameter after 5 days of 18.32 ± 2.18%, 17.72 ± 2.3% and 17.6 ± 1.81%, respectively, representing a significant increase over control diameters. In summary, this study has identified and characterized the presence and localization of all members of the family of platelet derived growth factors and receptors in the rat ovary and revealed a role for these growth factors in positively influencing early follicle growth.
