title: Characterization of persistent follicles induced by prolonged treatment with progesterone in dairy cows: an experimental model for the study of ovarian follicular cysts.
abstract: Cystic ovarian disease (COD) is a major factor contributing to poor reproductive efficiency of lactating dairy cows. The objective of the present study was to analyze the endocrine profile, growth dynamics, and histologic characteristics of persistent ovarian follicles-cysts developing in response to long-term administration of intermediate levels of progesterone. To this end, after synchronization of cows, a low dose of progesterone was administered for 5, 10, and 15 days after the expected day of ovulation in treated cows (groups P5, P10, and P15, respectively), using an intravaginal progesterone-releasing device. A significant increase in diameter was detected on Day 11 of progesterone treatment and thereafter (P < 0.05), and at Day 15 of persistence, the diameter of the persistent follicle reached a mean of 23 ± 0.6 mm. Microscopically, the persistent follicles had a complete granulosa, an intensely vascularized theca interna, and a collagenous theca externa layer. Temporal changes in the serum concentrations of estradiol, progesterone, and FSH were detected (effects of time, P < 0.01). Progesterone treatment completely inhibited the LH preovulatory surge in treated cows and affected the basal concentration of LH. The pulse frequency remained high at 5 and 10 days of persistence and declined (P < 0.05) after 15 days of persistence. The LH pulse concentration and pulse amplitude had a significant reduction (P < 0.05) during follicular persistence. Changes in the serum levels of estradiol, progesterone, 17-hydroxyprogesterone, and testosterone in serum and follicular fluid were also observed. In serum, estradiol increased gradually from proestrus to Day 10 of follicular persistence (P < 0.05), progesterone showed an increase (P < 0.05) at Day 5 of follicular persistence, 17-hydroxyprogesterone showed a significant decrease at 5 days of follicular persistence in relation to proestrus, and testosterone showed a significant increase (P < 0.05) from proestrus and Day 5 of persistence through Day 15 of follicular persistence. Correlation between serum and follicular fluid steroid concentrations was significant for testosterone (P < 0.0001) and not significant for estradiol and progesterone. These findings indicate that ovarian cysts in COD are similar in many ways to the persistent follicles induced by progesterone, with an analogous hormonal and morphologic context, thus confirming a local role of subluteal levels of progesterone in COD pathogenesis and in the regulatory mechanisms of the ovarian function.
authors.affiliation: Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina.
authors.forename: Pablo U
authors.initials: PU
authors.lastname: Díaz
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, New York, USA.
authors.forename: Matías L
authors.initials: ML
authors.lastname: Stangaferro
authors.affiliation: Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina.
authors.forename: Natalia C
authors.initials: NC
authors.lastname: Gareis
authors.affiliation: Department of Animal and Food Science, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Silvia
authors.affiliation: Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina.
authors.forename: Valentina
authors.initials: V
authors.lastname: Matiller
authors.affiliation: Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina.
authors.forename: Natalia R
authors.initials: NR
authors.lastname: Salvetti
authors.affiliation: Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina.
authors.forename: Florencia
authors.initials: F
authors.lastname: Rey
authors.affiliation: Cátedra de Teriogenología, Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina.
authors.forename: Fabián
authors.initials: F
authors.lastname: Barberis
authors.affiliation: Cátedra de Teriogenología, Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina.
authors.forename: Luciano
authors.initials: L
authors.lastname: Cattaneo
authors.affiliation: Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina. Electronic address: hhortega@fcv.unl.edu.ar.
authors.forename: Hugo H
authors.initials: HH
authors.lastname: Ortega
mesh_terms: D019326:17-alpha-Hydroxyprogesterone / Q000097:blood; D000282:Administration, Intravaginal; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000139:chemically induced* / Q000473:pathology; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D015571:Follicular Fluid / Q000737:chemistry; D007774:Lactation; D007986:Luteinizing Hormone / Q000097:blood; D010048:Ovarian Cysts / Q000139:chemically induced / Q000473:pathology / Q000662:veterinary*; D006080:Ovarian Follicle / Q000187:drug effects* / Q000473:pathology; D010053:Ovary / Q000000981:diagnostic imaging; D011359:Proestrus; D011374:Progesterone / Q000008:administration & dosage* / Q000009:adverse effects* / Q000097:blood; D013739:Testosterone / Q000032:analysis / Q000097:blood; D014463:Ultrasonography
chemical_list: D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D019326:17-alpha-Hydroxyprogesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
keywords: Endocrine profiles; FSH; Follicular dynamics; Follicular persistence; LH