An imbalance between apoptosis and proliferation contributes to follicular persistence in polycystic ovaries in rats

<p>Abstract</p> <p>Background</p> <p>Cystic ovarian disease is an important cause of infertility that affects bovine, ovine, caprine and porcine species and even human beings. Alterations in the ovarian micro-environment of females with follicular cysts could alter the normal processes of proliferation and programmed cell death in ovarian cells. Thus, our objective was to evaluate apoptosis and proliferation in ovarian cystic follicles in rats in order to investigate the cause of cystic follicle formation and persistence.</p> <p>Methods</p> <p>We compared the number of in situ apoptotic cells by TUNEL assay, expression of active caspase-3 and members of Bcl-2 family by immunohistochemistry; and cell proliferation by the expression of the proliferation markers: PCNA and Ki-67.</p> <p>Results</p> <p>The proliferation index was low in granulosa of tertiary and cystic follicles of light exposed rats when compared with tertiary follicles of control animals, while in theca interna only cystic follicles presented low proliferation index when compared with tertiary follicles (p < 0.05). The granulosa of cysts exhibited a similar cell DNA fragmentation to early atretic follicles. In the granulosa and theca interna, active caspase-3 shown similar immunostaining levels in tertiary and cystic follicles (p < 0.05). The granulosa cells presented high expression of Bcl-2, Bcl-xL and Bcl-w in the tertiary and cystic follicles with diminishing intensity in the atretic follicles, except with Bcl-w where the intensity was maintained in the atretic follicles (p < 0.05). The expression of Bax was weak in the healthy and cystic follicles. In the theca interna, Bcl-2 expression was the same as the pattern found in the granulosa; no differences were found between tertiary and cystic follicles from both groups for Bcl-xL and Bcl-w. The expression of Bax in this layer was higher in the tertiary follicles of the treated animals (p < 0.05) while the values for cystic follicles were similar to those in the tertiary follicles of controls. The theca externa showed low expression of the pro and anti-apoptotic proteins.</p> <p>Conclusion</p> <p>These results show that the combination of weak proliferation indices and low apoptosis observed in follicular cysts, could explain the cause of the slow growth of cystic follicles and the maintenance of a static condition without degeneration, which leads to their persistence. These alterations may be due to structural and functional modifications that take place in these cells and could be related to hormonal changes in animals with this condition.</p

An imbalance between apoptosis and proliferation contributes to follicular persistence in polycystic ovaries in rats

Background: Cystic ovarian disease is an important cause of infertility that affects bovine, ovine, caprine and porcine species and even human beings. Alterations in the ovarian micro-environment of females with follicular cysts could alter the normal processes of proliferation and programmed cell death in ovarian cells. Thus, our objective was to evaluate apoptosis and proliferation in ovarian cystic follicles in rats in order to investigate the cause of cystic follicle formation and persistence. Methods: We compared the number of in situ apoptotic cellsby TUNEL assay, expression of active caspase-3 and members of Bcl-2 family by immunohistochemistry; and cell proliferation by the expression of the proliferation markers: PCNA and Ki-67. Results: The proliferation index was low in granulosa of tertiary and cystic follicles of light exposed rats when compared with tertiary follicles of control animals, while in theca interna only cystic follicles presented low proliferation index when compared with tertiary follicles (p < 0.05). The granulosa of cysts exhibited a similar cell DNA fragmentation to early atretic follicles. In the granulosa and theca interna, active caspase-3 shown similar immunostaining levels in tertiary and cystic follicles (p < 0.05). The granulosa cells presented high expression of Bcl-2, Bcl-xL and Bcl-w in the tertiary and cystic follicles with diminishing intensity in the atretic follicles, except with Bcl-w where the intensity was maintained in the atretic follicles (p < 0.05). The expression of Bax was weak in the healthy and cystic follicles. In the theca interna, Bcl-2 expression was the same as the pattern found in the granulosa; no differences were found between tertiary and cystic follicles from both groups for Bcl-xL and Bcl-w. The expression of Bax in this layer was higher in the tertiary follicles of the treated animals (p < 0.05) while the values for cystic follicles were similar to those in the tertiary follicles of controls. The theca externa showed low expression of the pro and anti-apoptotic proteins. Conclusion: These results show that the combination of weak proliferation indices and low apoptosis observed in follicular cysts, could explain the cause of the slow growth of cystic follicles and the maintenance of a static condition without degeneration, which leads to their persistence. These alterations may be due to structural and functional modifications that take place in these cells and could be related to hormonal changes in animals with this conditionFacultad de Ciencias Veterinaria

Impaired insulin signaling pathway in ovarian follicles of cows with cystic ovarian disease

Cystic ovarian disease (COD) is an important cause of infertility in dairy cattle. Follicular cell steroidogenesis and proliferation in ovulatory follicles is stimulated by hormones such as insulin and its necessary post-receptor response. The aim of this study was to determine the expression of insulin receptor (IR), IR substrate-1 (IRS1) and phosphatidylinositol 3-kinase (PI3K), key intermediates in the insulin pathway, in control cows and cows with spontaneous COD and ACTH-induced COD. IR and IRS1 mRNA levels were greater in granulosa cells and lower in follicular cysts than in control tertiary follicles. PI3K mRNA levels were similar in all follicles evaluated, whereas the expression of IR, IRS1 and PI3K was similar in theca cells. Protein expression of IR was higher in control tertiary follicles than in the same structures in animals with COD and with cysts. IRS1 and PI3K protein expression showed the same pattern in tertiary and cystic follicles. However, the protein expression of subunit alpha p85 of PI3K was greater in theca cells from tertiary follicles than in cystic follicles. These results provide new insights into the insulin response in cows with COD. The lower gene and protein expressions of some insulin downstream effectors at an early stage of the signaling pathway could negatively influence the functionality of ovaries and contribute to follicle persistence.Fil: Hein, Gustavo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; ArgentinaFil: Panzani, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; ArgentinaFil: Rodríguez, Fernanda Mariel. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Salvetti, Natalia Raquel. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Díaz, Pablo Uriel. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Gareis, Natalia Carolina. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Benitez, G. A.. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Ortega, Hugo Hector. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Rey, Florencia. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Departamento de Ciencias Morfológicas. Laboratorio de Biología Celular y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentin

Modulation of insulin response in ovarian cattle and its relationship with cystic ovarian disease

La enfermedad quística ovárica bovina es una importante enfermedad que afecta la fertilidad del ganado bovino lechero. Diversos procesos ováricos tales como la proliferación celular y la esteroidogénesis se encuentran regulados por numerosas hormonas entre las que se encuentra la insulina. La respuesta a esta hormona se desencadena luego de la unión a su receptor específico. El objetivo de la presente revisión es analizar la función de intermediarios claves en la vía de señalización intracelular, que actúan en los primeros estadios involucrados en la respuesta a insulina. Se analizan el receptor de insulina (IR), el sustrato -1 del IR (IRS1) y la enzima fosfatidilinositol 3-quinasa (PI3K) denotando modificaciones ocurridas en folículos quísticos que podrían influenciar negativamente en la funcionalidad de ovarios y contribuir a la persistencia folicular.Cystic ovarian disease (COD) is an important disease affecting fertility in dairy cattle. Several ovarian processes such as cell proliferation and follicular cell steroidogenesis are regulated by numerous hormones including insulin. The hormone response is triggered after the binding to its receptor. The aim of this review is to analyze the role of key intermediates in the intracellular signaling pathway that act in the early stages of the insulin response. Therefore, insulin receptor (IR), IR substrate-1 (IRS1) and phosphatidylinositol-3-kinase (PI3K) are analyzed showing changes that occur in cystic follicles and which could negatively influence the functionality of ovaries and contribute to follicle persistence.Sociedad de Ciencias Morfológicas de La Plat