title: Ovine secondary follicles vitrified out the ovarian tissue grow and develop in vitro better than those vitrified into the ovarian fragments.
abstract: Cryopreservation of preantral follicles is a promising technique to preserve female fertility. The aim of this study was to evaluate the effect of vitrification on the development of secondary follicles included in ovarian tissue or isolated after microdissection. An important end point included is the capacity of grown oocytes to resume meiosis. Sheep ovarian cortexes were cut into fragments and split into three different groups: (1) fresh (control): secondary follicles isolated without any previous vitrification; (2) follicle-vitrification (follicle-vit): secondary follicles vitrified in isolated form; and (3) tissue-vitrification (tissue-vit): secondary follicles vitrified within fragments of ovarian tissue (in situ former) and subsequently subjected to isolation. From the three groups, isolated secondary follicles were submitted to IVC for 18 days. After IVC, cumulus-oocyte complexes (COCs) were harvested from follicles. As an additional control group, in vivo grown, in vivo-grown COCs were collected from antral ovarian follicles. All, recovered COCs were matured and the chromatin configuration was evaluated. Data were analyzed by ANOVA, and the means were compared by Student-Newman-Keuls test, and by chi-square. Differences were considered to be significant when P < 0.05. Isolated preantral follicles from all treatments had normal morphology, antrum formation, and low follicle degeneration after IVC. The growth rate between control and follicle-vit did not differ (P > 0.05), and was higher (P < 0.05) than for tissue-vit. The percentage of follicles that decreased diameter during IVC was significantly higher in tissue-vit than the in follicle-vit. Recovery rate of oocytes from normal follicles was higher in follicle-vit than in tissue-vit. Furthermore, oocyte viability was lower in tissue-vit than other treatments, and follicle-vit did not differ from control and in vivo grown. The percentage of oocytes meiosis resuming was not different between treatments except for in vivo grown. After vitrification, only follicle-vit showed metaphase I oocyte. We conclude that secondary follicles vitrified after isolation displayed a better follicular growth rate, oocyte viability, percentage of oocytes reaching the metaphase I stage, and fewer follicles with decreased diameter after IVC.
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil. Electronic address: lunardi.franciele@gmail.com.
authors: Franciele Osmarini
authors: FO
authors: Lunardi
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: Francisco Leo Nascimento
authors: FL
authors: de Aguiar
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: Ana Beatriz Graça
authors: AB
authors: Duarte
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: Valdevane Rocha
authors: VR
authors: Araújo
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: Laritza Ferreira
authors: LF
authors: de Lima
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: Naiza Arcângela
authors: NA
authors: Ribeiro de Sá
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: Hudson Henrique
authors: HH
authors: Vieira Correia
authors: Laboratory of Wild Animal Biology and Medicine, Federal University of Pará, Belem, Brazil.
authors: Sheyla Farhayldes Souza
authors: SF
authors: Domingues
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: Cláudio Cabral
authors: CC
authors: Campello
authors: Follicle Biology Laboratory, Center for Reproductive Medicine, UZ Brussel, Brussels, Belgium.
authors: Johan
authors: J
authors: Smitz
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: José Ricardo
authors: JR
authors: de Figueiredo
authors: Laboratory of Manipulation of Oocytes and Ovarian Pre-antral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, Ceará State University, Fortaleza, CE, Brazil.
authors: Ana Paula
authors: AP
authors: Ribeiro Rodrigues
mesh_terms: D000818:Animals; D015925:Cryopreservation; D005260:Female; D008540:Meiosis; D006080:Ovarian Follicle / Q000502:physiology*; D012756:Sheep / Q000502:physiology*; D014021:Tissue Preservation / Q000379:methods / Q000662:veterinary*; D058989:Vitrification
keywords: Cryopreservation; Follicular development; Oocyte maturation; Ovary; Ovine/sheep