Theca Interna: The Other Side of Bovine Follicular Atresia1

Clark, L; Irving-Rodgers, Helen F.; Dharmarajan, Arun; Rodgers, Raymond J.

doi:10.1095/biolreprod.104.029652

Cited by 31 publications

(29 citation statements)

References 33 publications

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“…We observed that periantral cells die by pycnosis or apoptosis and are phagocytosed and removed by neighbouring granulosa cells, as demonstrated previously (Byskov 1979, Van Wezel et al 1999. Peribasal cells, on the other hand, did not become apoptotic, but rather differentiated morphologically and functionally into Gene expression in the theca of bovine follicles 459 luteal-like cells, which lost the ability to express follistatin, but instead expressed StAR (present study) and P450 sidechain cleavage (Clark et al 2004). It has been hypothesized that there are two types of atresia in small bovine follicles: basal and antral , Clark et al 2004.…”

Section: Discussionmentioning

confidence: 49%

“…Peribasal cells, on the other hand, did not become apoptotic, but rather differentiated morphologically and functionally into Gene expression in the theca of bovine follicles 459 luteal-like cells, which lost the ability to express follistatin, but instead expressed StAR (present study) and P450 sidechain cleavage (Clark et al 2004). It has been hypothesized that there are two types of atresia in small bovine follicles: basal and antral , Clark et al 2004. Alternatively, we suggest that these are consecutive stages of the atretic process: in the early stage of atresia, periantral granulosa cells die by apoptosis or pyknosis and are removed from the follicle.…”

Section: Discussionmentioning

confidence: 49%

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Gene expression for LH receptor, 17α-hydroxylase and StAR in the theca interna of preantral and early antral follicles in the bovine ovary

Braw–Tal

Roth²

2005

Reproduction

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The onset of gene expression for three proteins that play pivotal roles in theca interna function, namely the LH receptor (LH-R), cytochrome P450 17a-hydroxylase (17aOH) and the steroidogenic acute regulatory protein (StAR), was determined. Ovaries were obtained on day 9 of the oestrus cycle from mature synchronized dairy cows (n 5 5) and gene expression in preantral and antral follicles up to 4 mm in diameter was evaluated by in situ hybridization. LH-R and 17aOH mRNAs were observed first, in the theca interna of large preantral follicles (type 4), concurrent with its morphological differentiation. StAR mRNA appeared later during follicular growth, in follicles >1 mm in diameter (type 6). LH-R and 17aOH mRNAs were found exclusively in the thecal cells, whereas StAR mRNA appeared in thecal cells, granulosa cells of late atretic follicles and oocytes. In early atresia, thecal cells expressed all three mRNAs, and their expression decreased gradually as atresia progressed. Atresia in granulosa cells was characterized by massive apoptosis of periantral, but not peribasal cells, that differentiated into luteallike cells expressing StAR. In summary, our study suggests that in spite of the presence of 17aOH, a key enzyme in steroidogenesis, the ability to produce steroids by bovine follicles smaller than 1 mm in diameter must be very limited due to the absence of StAR protein.During the early stages of atresia, thecal cells remain morphologically and functionally healthy, and continue to express all three studied mRNAs.

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Section: Discussionmentioning

confidence: 49%

Section: Discussionmentioning

confidence: 49%

Gene expression for LH receptor, 17α-hydroxylase and StAR in the theca interna of preantral and early antral follicles in the bovine ovary

Braw–Tal

Roth²

2005

Reproduction

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“…This may be because the granulosa cells that do not receive direct oxygenation are more sensitive to anoxia than theca cell layer (Rodgers and Irving-Rodgers, 2010) and, therefore, the granulosa cells undergo apoptosis earlier (Rosales-Torres and Guzman, 2008). Several authors have shown that during atresia of bovine follicle, apoptosis occurs earlier in the granulosa cells then in the theca cell layer (Clark et al, 2004). These studies could explain why differences in CER concentrations between healthy and atretic follicles were found in the granulosa cells, but not in the theca cell layer.…”

Section: Discussionmentioning

confidence: 92%

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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“…During follicle growth, different cell(s) may vary in their susceptibility to death and if these cells are irreplaceable then this would result in follicular atresia. At the bovine preantral stage, oocytes are reported to be the first to die (Rajakoski 1960), in contrast to the antral stage where granulosa cells die first, and in one form of atresia (discussed below) thecal cells, including steroidogenic and endothelial cells (Clark et al 2004), also die very early in atresia. When atresia is initiated by a large amount of cell death, this could be due to loss of growth factor support such as TGFa (Wang et al 2002), or that expression of Fas or Fas ligand (Porter et al 2000, Quirk et al 2004) could be involved in initiating the process.…”

Section: Which Cell(s) Die First Andmentioning

confidence: 99%

Morphological classification of bovine ovarian follicles

Rodgers¹,

Irving-Rodgers²

2010

Reproduction

129

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Follicle classification is an important aid to the understanding of follicular development and atresia. Some bovine primordial follicles have the classical primordial shape, but ellipsoidal shaped follicles with some cuboidal granulosa cells at the poles are far more common. Preantral follicles have one of two basal lamina phenotypes, either a single aligned layer or one with additional layers. In antral follicles !5 mm diameter, half of the healthy follicles have columnar shaped basal granulosa cells and additional layers of basal lamina, which appear as loops in cross section ('loopy'). The remainder have aligned single-layered follicular basal laminas with rounded basal cells, and contain better quality oocytes than the loopy/columnar follicles. In sizes O5 mm, only aligned/rounded phenotypes are present. Dominant and subordinate follicles can be identified by ultrasound and/or histological examination of pairs of ovaries. Atretic follicles !5 mm are either basal atretic or antral atretic, named on the basis of the location in the membrana granulosa where cells die first. Basal atretic follicles have considerable biological differences to antral atretic follicles. In follicles O5 mm, only antral atresia is observed. The concentrations of follicular fluid steroid hormones can be used to classify atresia and distinguish some of the different types of atresia; however, this method is unlikely to identify follicles early in atresia, and hence misclassify them as healthy. Other biochemical and histological methods can be used, but since cell death is a part of normal homoeostatis, deciding when a follicle has entered atresia remains somewhat subjective.

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Theca Interna: The Other Side of Bovine Follicular Atresia1

Cited by 31 publications

References 33 publications

Gene expression for LH receptor, 17α-hydroxylase and StAR in the theca interna of preantral and early antral follicles in the bovine ovary

Gene expression for LH receptor, 17α-hydroxylase and StAR in the theca interna of preantral and early antral follicles in the bovine ovary

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

Morphological classification of bovine ovarian follicles

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