Vascular supply as a discriminating factor for pig preantral follicle selection

Martelli, Alessandra; Bernabò, Nicola; Berardinelli, Paolo; Russo, Valentina; Rinaldi, Carlo; Giacinto, Oriana Di; Mauro, Annunziata; Barboni, Barbara

doi:10.1530/rep-08-0117

Cited by 20 publications

(36 citation statements)

References 62 publications

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“…The higher S1P and CER concentrations found in our study in the theca cell layer as compared with the granulosa cells, for both types of follicles, may be explained by the rich vasculature that exists in internal and external theca cells, and the resulting increase in endothelial cells (40%) (Martelli et al, 2009). It was shown that aortic bovine endothelial cells are rich in sphingomyelinases, which synthesise CER (Mulders et al, 2007).…”

Section: Discussionmentioning

confidence: 42%

Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles

Hernández‐Coronado

Guzmán

Espinosa-Cervantes

et al. 2015

Animal

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The follicle destiny towards ovulation or atresia is multi-factorial in nature and involves outcries, paracrine and endocrine factors that promote cell proliferation and survival (development) or unchain apoptosis as part of the atresia process. In several types of cells, sphingosine-1-phospate (S1P) promotes cellular proliferation and survival, whereas ceramide (CER) triggers cell death, and the S1P/CER ratio may determine the fate of the cell. The aim of present study was to quantify S1P and CER concentrations and their ratio in bovine antral follicles of 8 to 17 mm classified as healthy and atretic antral follicles. Follicles were dissected from cow ovaries collected from a local abattoir. The theca cell layer, the granulosa cells and follicular fluid were separated, and 17β-estradiol (E2) and progesterone (P4) concentrations were measured in the follicular fluid by radioimmunoassay. Based on the E2/P4 ratio, the follicles were classified as healthy (2.2 ± 0.3) or atretic (0.2 ± 0.3). In both follicular compartments (granulosa and theca cell layer), sphingolipids were extracted and S1P and CER concentrations were quantified by HPLC (XTerra RP18; 5 µm, 3.0 × 150 mm column). Results showed that in both follicular compartments, S1P concentrations were higher in healthy antral follicles than in atretic antral follicles (P < 0.05). The concentration of CER in the granulosa cells was higher in atretic antral follicles than in healthy antral follicles, but no differences were observed in the theca cell layer. The S1P/CER ratio in both follicular compartments was also higher in healthy antral follicles. Interestingly, in these follicles, there was a 45-fold greater concentration of S1P than CER in the granulosa cells (P < 0.05), whereas in the theca cell layer, S1P had only a 14-fold greater concentration than CER when compared with atretic antral follicles. These results suggest that S1P plays a role in follicle health, increasing cellular proliferation and survival. In contrast, reduction of S1P and the S1P/CER in the antral follicle could trigger cellular death and atresia.Keywords: bovine, antral follicle, atresia, ceramide, sphingosine-1-phospohate Implications Follicular development involves selection of a follicle apt to grow in response to stimuli (FSH and LH) that induce proliferation and survival of follicular cells so that it reaches ovulation. However, if follicles do not receive these stimuli (reduction in FSH and LH or their receptors), cellular death signals are triggered and the follicle fate will be atresia. Sphingosine-1-phospohate (S1P) induces survival and proliferation of cells, whereas ceramide (CER) is involved in cellular death. The present study reveals that S1P and CER concentrations differ within follicular status suggesting these sphingolipids may participate in follicular health or atresia.Knowledge of signals that control follicular development and atresia may help us to improve follicular development and thus reproductive performance. IntroductionThe development of bovine ovarian follic...

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Section: Discussionmentioning

confidence: 42%

Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles

Hernández‐Coronado

Guzmán

Espinosa-Cervantes

et al. 2015

Animal

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“…Blood vessels allow growing follicles to acquire an increasing amount of nutrients, precursors, and hormones, as to release steroids and other regulating ovarian hormonal molecules to the systemic circulation [8], [13]. Several factors drive follicle angiogenesis indirectly controlling ovarian follicle development [6], [7], [11], [14]–[16]. VEGF is recognized to be a key molecule [13], [16], [17].…”

Section: Introductionmentioning

confidence: 99%

Effect of Antiprogesterone RU486 on VEGF Expression and Blood Vessel Remodeling on Ovarian Follicles before Ovulation

et al. 2014

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BackgroundThe success of ovarian follicle growth and ovulation is strictly related to the development of an adequate blood vessel network required to sustain the proliferative and endocrine functions of the follicular cells. Even if the Vascular Endothelial Growth Factor (VEGF) drives angiogenesis before ovulation, the local role exerted by Progesterone (P4) remains to be clarified, in particular when its concentration rapidly increases before ovulation.AimThis in vivo study was designed to clarify the effect promoted by a P4 receptor antagonist, RU486, on VEGF expression and follicular angiogenesis before ovulation, in particular, during the transition from pre to periovulatory follicles induced by human Chorionic Gonadotropins (hCG) administration.Material and MethodsPreovulatory follicle growth and ovulation were pharmacologically induced in prepubertal gilts by combining equine Chorionic Gonadotropins (eCG) and hCG used in the presence or absence of RU486. The effects on VEGF expression were analyzed using biochemical and immunohistochemical studies, either on granulosa or on theca layers of follicles isolated few hours before ovulation. This angiogenic factor was also correlated to follicular morphology and to blood vessels architecture.Results and ConclusionsVEGF production, blood vessel network and follicle remodeling were impaired by RU486 treatment, even if the cause-effect correlation remains to be clarified. The P4 antagonist strongly down-regulated theca VEGF expression, thus, preventing most of the angiogenic follicle response induced by hCG. RU486-treated follicles displayed a reduced vascular area, a lower rate of endothelial cell proliferation and a reduced recruitment of perivascular mural cells. These data provide important insights on the biological role of RU486 and, indirectly, on steroid hormones during periovulatory follicular phase. In addition, an in vivo model is proposed to evaluate how periovulatory follicular angiogenesis may affect the functionality of the corpus luteum (CL) and the success of pregnancy.

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“…gonadotropins and growth factors, and oxygen and metabolites via the blood stream. Early follicle stages depend upon the vascular system of the ovarian stroma for their supply, whereas antral follicles have an autonomous capillary network provided by the theca interna and externa [17], [18]. The establishment of the thecal vascular network is induced and regulated by granulosa cell-secreted factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF2), epidermal growth factor, IGF-1 and transforming growth factor β (TGFβ) (reviewed in [18]).…”

Section: Introductionmentioning

confidence: 99%

Transcriptome Profiling of the Theca Interna in Transition from Small to Large Antral Ovarian Follicles

et al. 2014

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The theca interna layer of the ovarian follicle forms during the antral stage of follicle development and lies adjacent to and directly outside the follicular basal lamina. It supplies androgens and communicates with the granulosa cells and the oocyte by extracellular signaling. To better understand developmental changes in the theca interna, we undertook transcriptome profiling of the theca interna from small (3–5 mm, n = 10) and large (9–12 mm, n = 5) healthy antral bovine follicles, representing a calculated >7-fold increase in the amount of thecal tissue. Principal Component Analysis and hierarchical classification of the signal intensity plots for the arrays showed no clustering of the theca interna samples into groups depending on follicle size or subcategories of small follicles. From the over 23,000 probe sets analysed, only 76 were differentially expressed between large and small healthy follicles. Some of the differentially expressed genes were associated with processes such as myoblast differentiation, protein ubiquitination, nitric oxide and transforming growth factor β signaling. The most significant pathway affected from our analyses was found to be Wnt signaling, which was suppressed in large follicles via down-regulation of WNT2B and up-regulation of the inhibitor FRZB. These changes in the transcriptional profile could have been due to changes in cellular function or alternatively since the theca interna is composed of a number of different cell types it could have been due to any systematic change in the volume density of any particular cell type. However, our study suggests that the transcriptional profile of the theca interna is relatively stable during antral follicle development unlike that of granulosa cells observed previously. Thus both the cellular composition and cellular behavior of the theca interna and its contribution to follicular development appear to be relatively constant throughout the follicle growth phase examined.

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Vascular supply as a discriminating factor for pig preantral follicle selection

Cited by 20 publications

References 62 publications

Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles

Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles

Effect of Antiprogesterone RU486 on VEGF Expression and Blood Vessel Remodeling on Ovarian Follicles before Ovulation

Transcriptome Profiling of the Theca Interna in Transition from Small to Large Antral Ovarian Follicles

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