scholarly journals Identification of optimal assisted aspiration conditions of oocytes for use in porcine in vitro maturation: A re‐evaluation of the relationship between the cumulus oocyte complex and oocyte quality

2018 ◽  
Author(s):  
Giuseppe Silvestri ◽  
Claudia C. Rathje ◽  
Simon C. Harvey ◽  
Rebecca L. Gould ◽  
Grant A. Walling ◽  
...  
Keyword(s):  
In Vitro Maturation ◽  
Oocyte Quality ◽  
Cumulus Oocyte Complex ◽  
The Relationship

scholarly journals Oocyte Quality and Subsequent In Vitro Maturation of Sheep Oocyte-Cumulus Complex from Ovary with Presence and Absence of Corpus Luteum

2017 ◽  
Vol 3 (6) ◽  
pp. 166 ◽  
Author(s):  
Rini Widyastuti ◽  
Mas Rizky A.A. Syamsunarno ◽  
Takdir Saili ◽  
Arief Boediono
Keyword(s):  
Corpus Luteum ◽  
In Vitro Maturation ◽  
Polar Body ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
Maturation Stage ◽  
Cumulus Oocyte Complex ◽  
First Polar Body ◽  
Maturation Rate

In vitro maturation is the crucial step for in vitro embryo production. It needs a large number of oocytes as source gamet cells recovered. The present study is aimed to assess the influence of corpus luteum on the average number oocytes harvested, COCs quality and subsequent maturation of immature oocytes recovered from sheep ovaries. Sheep ovaries were collected from local slaughterhouse and COCs were collected by using slicing method. Collected COCs were graded into three categories dependent upon cumulus cells surrounding them and the homogenous of cytoplasm. COCs were maturated in maturation media at 5% CO2 for 24 hours. Maturation of oocytes evaluated base on the expansion of cumulus cells and extrusion of the first polar body. There was significantly higher on average of COCs harvested from ovaries with corpus luteum compared without corpus luteum. The presence of Corpus luteum did not affect the COCs quality and ability to reach the maturation stage. However, there was a dramatic effect of cultured COCs quality on maturation rate both groups. Collectively, these results indicate that COCs quality is the main factor affecting the subsequent of oocytes matured in vitro. Keywords: Corpus luteum; cumulus oocyte complex; in vitro maturation; maturation rate; ovaries

Glucocorticoid metabolism in bovine cumulus-oocyte complex during in vitro maturation

2014 ◽  
Author(s):  
Masafumi Tetsuka ◽  
Ryo Takagi ◽  
Nobuhiro Ambo ◽  
Yuta Zempo ◽  
Asuka Onuma
Keyword(s):  
In Vitro Maturation ◽  
Cumulus Oocyte Complex ◽  
Glucocorticoid Metabolism

scholarly journals Effects of BMP15 and GDF9 on Ovine Oocytes in an In Vitro Maturation System

2021 ◽  
Author(s):  
◽  
Aanchal Singh
Keyword(s):  
Cell Death ◽  
Litter Size ◽  
In Vitro Maturation ◽  
Cumulus Cell ◽  
Oocyte Quality ◽  
Mature Oocyte ◽  
High Ratio ◽  
High Fecundity ◽  
Species Specific

<p>Oocyte developmental competency is the intrinsic measure of oocyte quality and the capacity for a mature oocyte to support the early stages of embryo development and implantation. Oocyte-secreted factors (OSFs), such as growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15), play a pivotal role in regulating the synchrony of various complex maturation events within the cumulus-oocyte complex (COC) through the induction of paracrine and endocrine signalling. These proteins act synergistically to influence the proliferation and differentiation of granulosa cells (GCs), cumulus cell (CC) expansion, promote survival, ovulation, the attainment of developmental competency and fertility. Species-specific ratios suggest that poly-ovulatory mammals have increased fecundity due to high ratios of GDF9:BMP15, which is directly reflected in their large litter size. Interestingly, it has also been found that higher ratios of GDF9:BMP15 also increased blastocyst rate in sheep implying that these embryos develop from oocytes that are more developmentally competent.  In this study, I investigated the hypothesis that supplementing a commercial in vitro maturation (IVM) system with a high ratio of GDF9:BMP15 would increase the developmental competency sheep oocytes; a species with low-moderate litter size. To test this hypothesis, ovine oocytes were matured in a biphasic IVM system containing GDF9 and BMP15 at three divergent ratios (1:6, 1:1, 6:1). The results herein show that the 6:1 ratio resulted in higher levels of reagent transfer to the ovine oocyte through gap junctions (GJs) after 24 hours of incubation. Similarly, it was also observed that at the higher ratio, glutathione (GSH) levels were higher at 7.5 hours of incubation. The high GDF9:BMP15 ratio also facilitated the increased consumption of pyruvate by the COC consistently throughout the culture period. Importantly, the high GDF9:BMP15 ratio showed higher expression of the gene that encodes GJ (CX43) at 24 hours relative to the control. It was also demonstrated through decreased apoptotic factor (BAX:BCL2) ratios, that the addition of OSFs, regardless of ratio, protected against cell death. In summary, this study provides novel results that support the notion that a high GDF9:BMP15 ratio improves oocyte quality by delaying the timing of meiotic resumption. This subsequently improves the transport of key metabolites and antioxidants to protect against oxidative stress and cell death and aid in the completion of maturation, ultimately resulting in the increased developmental competency observed in high fecundity poly-ovulatory species.</p>

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