Ultrastructure of isolated mouse ovarian follicles cultured in vitro

Reproductive Biology and Endocrinology

Research

Stefania A Nottola¹  Cecilia Motta¹  Sandra Cecconi²  Serena Bianchi²  Maria A Continenza²  Gianna Rossi²  Guido Macchiarelli³ 

[1] Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, "La Sapienza" University of Rome, Rome, Italy;Department of Health Sciences, University of L'Aquila,, L'Aquila, Italy;Department of Health Sciences, University of L'Aquila,, L'Aquila, Italy;Centre of Microscopy, University of L'Aquila,, L'Aquila, Italy;

关键词: Zona Pellucida;    Ovarian Follicle;    Preantral Follicle;    Cortical Granule;    Follicle Growth;   

DOI  :  10.1186/1477-7827-9-3

 received in 2010-10-04, accepted in 2011-01-13,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundIn vitro maturation of ovarian follicles, in combination with cryopreservation, might be a valuable method for preserving and/or restoring fertility in mammals with impaired reproductive function. Several culture systems capable of sustaining mammalian follicle growth in vitro have been developed and many studies exist on factors influencing the development of in vitro grown oocytes. However, a very few reports concern the ultrastructural morphology of in vitro grown follicles.MethodsThe present study was designed to evaluate, by transmission and scanning electron microscopy, the ultrastructural features of isolated mouse preantral follicles cultured in vitro for 6 days in a standard medium containing fetal calf serum (FCS). The culture was supplemented or not with FSH.ResultsThe follicles cultured in FCS alone, without FSH supplementation (FCS follicles), did not form the antral cavity. They displayed low differentiation (juxta-nuclear aggregates of organelles in the ooplasm, a variable amount of microvilli on the oolemma, numerous granulosa cell-oolemma contacts, signs of degeneration in granulosa cell compartment). Eighty (80)% of FSH-treated follicles formed the antral cavity (FSH antral follicles). These follicles showed various ultrastructural markers of maturity (spreading of organelles in ooplasm, abundant microvilli on the oolemma, scarce granulosa cell-oolemma contacts, granulosa cell proliferation). Areas of detachment of the innermost granulosa cell layer from the oocyte were also found, along with a diffuse granulosa cell loosening compatible with the antral formation. Theca cells showed an immature morphology for the stage reached. Twenty (20)% of FSH-treated follicles did not develop the antral cavity (FSH non-antral follicles) and displayed morphological differentiation features intermediate between those shown by FCS and FSH antral follicles (spreading of organelles in the ooplasm, variable amount of microvilli, scattered granulosa cell-oolemma contacts, signs of degeneration in granulosa cell compartment).ConclusionsIt is concluded that FSH supports the in vitro growth of follicles, but the presence of a diffuse structural granulosa cell-oocyte uncoupling and the absence of theca development unveil the incomplete efficiency of the system. The present study contributes to explain, from a morphological point of view, the effects of culture conditions on the development of mouse in vitro grown follicles and to highlight the necessity of maintaining efficient intercellular communications to obtain large numbers of fully-grown mature germ cells.

【 授权许可】

Unknown   
© Nottola et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.