Identification of cells migrating from the thecal layer of ovarian follicles
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In the mammalian ovary, oocytes are contained within ovarian follicles. These consist in an oocyte surrounded by supporting cells: an inner layer of granulosa cells and an outer layer of thecal cells separated by a basal lamina. At any one time, a developing cohort of follicles exists, from which only a small species-specific number are selected for continued development towards ovulation, with the remainder dying by follicular atresia. Here, we use in vitro methods to study interactions between two follicles in culture (follicle co-cultures). We show that, when two individual follicles are grown together in culture, cells and cellular processes migrate from the outer thecal layer of one follicle to the thecal layer of the other co-cultured follicle. These cells are identified as a mixed population containing primarily endothelial but also neuronal cells. Both are able to migrate through the ovarian interstitum, making contact with the basal lamina of other follicles and with similar cells from these other follicles. Networks of such cells might be involved in interfollicular communication and in the coordination of follicle selection for ovulation.
KeywordsOvary Follicle Culture Endothelial cells Neuron Mouse
We thank Trudi Gillespie from the IMPACT imaging facility at the University of Edinburgh for all her technical assistance with confocal microscopy. Thanks are also due to Tom Pratt for donating tau-GFP mice, to Richard Ribchester and Derek Thomson for donating thy1-YFP mice, to Richard Anderson for the P450scc antibody and to Dave Price for donating brains of C57Bl6J mice. Vivian Allison, Federica Lopes, Alison Murray and Rowina Smith helped with cultures and general advice.
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