Poster Presentation Annual Meetings of the Endocrine Society of Australia and Society for Reproductive Biology and Australia and New Zealand Bone and Mineral Society 2016

Stromal development of the bovine fetal ovary (#439)

Monica Hartanti 1 , Katja Hummitzsch 1 , Helen Irving-Rodgers 2 , Wendy Bowner 1 , Viv Perry 3 , Ray Rodgers 1
  1. Obstetrics and Gynaecology, University of Adelaide, Adelaide, SA, Australia
  2. School of Medicine Science, Griffith University, Gold Coast Campus, Gold Coast, Queensland, Australia
  3. School of Veterinary and Medical Science, University of Nottingham, Sutton Bonington, United Kingdom

Stroma is important in the development of the fetal ovary. A recent study has suggested that the stroma penetrates from the mesonephros and expands in the developing ovary and might play a role in the formation of ovigerous cords, follicles, and the ovarian surface epithelium [1]. The aim of our study was to morphometrically analyse the development of the ovarian stroma during gestation. We collected and weighted 28 ovaries from bovine fetuses, and identified the gender of the small fetuses less than 10 cm by analysing the SRY gene.  We analysed the ovarian cortex and quantitated the cortical stromal volume.  The stromal volume density was measured by quantitative immunohistochemistry using collagen type I (a marker of the stromal fibrillar matrix) to identify the stromal area in the ovarian cortex. Furthermore, using the Ki67 proliferation marker, we calculated the proliferation index in the stromal and non-stromal areas of the cortex. The stromal volume density and total stromal volume in the fetal bovine ovarian cortex increased throughout the gestation and were both strongly correlated with crown-rump length (R2 = 0.8065, P < 0.01 and R2 = 0.8194, P < 0.01, respectively). Interestingly, the numerical density of proliferating cells and the proliferation index in stromal region decreased throughout development, whereas in the non-stromal region, both parameters sharply declined to a minimum when fetuses reached a crown-rump length of 40 cm. They remained low until the end of gestation. Furthermore, the numerical density of cells for both stromal and non-stromal regions did not change throughout gestation. Our study suggests that in fetal bovine ovarian development, there is an extensive expansion of stromal tissue coupled with a decrease in stromal cell proliferation, which might be due to the decreased number of apoptotic cells and/or increased number of cells migrating from the mesonephros or ovarian medulla.