scholarly journals Presence of LH receptor mRNA in granulosa cells as a potential marker of oocyte developmental competence and characterization of the bovine splicing isoforms

Reproduction ◽  
2003 ◽  
pp. 437-446 ◽  
Author(s):  
C Robert ◽  
D Gagne ◽  
JG Lussier ◽  
D Bousquet ◽  
FL Barnes ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Culture Media ◽  
Protein Product ◽  
Blastocyst Stage ◽  
Culture Conditions ◽  
Developmental Competence ◽  
Lh Receptor ◽  
Potential Marker ◽  
A Cell

As the expression of the LH receptor (LH-R) in granulosa cells is thought to be associated with later stages of folliculogenesis, this study was undertaken to evaluate the presence of LH-R mRNA as a suitable marker for developmental competence of oocytes. Granulosa cells and cumulus-oocyte complexes (COCs) were recovered from cows that had received ovarian stimulation. The COCs were subjected to embryo production procedures in vitro to assess the embryonic potential of the oocyte, and the corresponding granulosa cells were used to evaluate the presence of LH-R mRNA by RT-PCR. The presence of LH-R transcripts in granulosa cells is not a key characteristic of a follicle bearing a competent oocyte, although a higher proportion of oocytes reach the blastocyst stage when LH-R mRNA is detected in the granulosa cells. Different LH-R isoforms were cloned and sequence discrepancies among six of the isoforms enabled the design of specific oligonucleotides to study the presence of the isoforms in different follicular cells. All LH-R transcripts studied and the 80 kDa protein product corresponding to the full length receptor were found in granulosa cells of small (< 4 mm) and large (> 5 mm) follicles. When the granulosa cells were cultured, the transcripts were downregulated by the culture conditions; downregulation was more acute in granulosa cells from small follicles. The addition of LH to the culture media enhanced LH-R mRNA downregulation. The presence of several LH-R transcript isoforms was tissue specific and in the theca cells LH-R mRNA was restricted mainly to cells from larger follicles. This finding indicates that the expression and the splicing of LH-R mRNA are regulated in a cell-specific and follicular size-specific manner.

scholarly journals MicroRNAs from Extracellular Vesicles Secreted by Bovine Embryos as Early Biomarkers of Developmental Competence

2020 ◽  
Vol 21 (23) ◽  
pp. 8888
Author(s):  
Bárbara Melo-Baez ◽  
Yat S. Wong ◽  
Constanza J. Aguilera ◽  
Joel Cabezas ◽  
Ana C. F. Mançanares ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Fatty Acid Biosynthesis ◽  
Culture Media ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Target Cells ◽  
Bovine Embryos ◽  
Developmental Potential ◽  
Maternal Communication

During early development, embryos secrete extracellular vesicles (EVs) that participate in embryo–maternal communication. Among other molecules, EVs carry microRNAs (miRNAs) that interfere with gene expression in target cells; miRNAs participate in embryo–maternal communication. Embryo selection based on secreted miRNAs may have an impact on bovine breeding programs. This research aimed to evaluate the size, concentration, and miRNA content of EVs secreted by bovine embryos with different developmental potential, during the compaction period (days 3.5–5). Individual culture media from in vitro–produced embryos were collected at day 5, while embryos were further cultured and classified at day 7, as G1 (conditioned-culture media by embryos arrested in the 8–16-cells stage) and G2 (conditioned-culture media by embryos that reached blastocyst stages at day 7). Collected nanoparticles from embryo conditioned culture media were cataloged as EVs by their morphology and the presence of classical molecular markers. Size and concentration of EVs from G1 were higher than EVs secreted by G2. We identified 95 miRNAs; bta-miR-103, bta-miR-502a, bta-miR-100, and bta-miR-1 were upregulated in G1, whereas bta-miR-92a, bta-miR-140, bta-miR-2285a, and bta-miR-222 were downregulated. The most significant upregulated pathways were fatty acid biosynthesis and metabolism, lysine degradation, gap junction, and signaling pathways regulating pluripotency of stem cells. The characteristics of EVs secreted by bovine embryos during the compaction period vary according to embryo competence. Embryos that reach the blastocyst stage secrete fewer and smaller vesicles. Furthermore, the loading of specific miRNAs into the EVs depends on embryo developmental competence.

Generation of parthenogenetic goat blastocysts: effects of different activation methods and culture media

Zygote ◽  
2014 ◽  
Vol 23 (3) ◽  
pp. 327-335 ◽  
Author(s):  
Hruda Nanda Malik ◽  
Dinesh Kumar Singhal ◽  
Shrabani Saugandhika ◽  
Amit Dubey ◽  
Ayan Mukherjee ◽  
...  
Keyword(s):  
Culture Media ◽  
Combined Treatment ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
Cell Stage ◽  
Quantitative Expression ◽  
Pattern Of Variation ◽  
Better Than

SummaryThe present study was carried out to investigate the effects of different activation methods and culture media on the in vitro development of parthenogenetic goat blastocysts. Calcium (Ca2+) ionophore, ethanol or a combination of the two, used as activating reagents, and embryo development medium (EDM), modified Charles Rosenkrans (mCR2a) medium and research vitro cleave (RVCL) medium were used to evaluate the developmental competence of goat blastocysts. Quantitative expression of apoptosis, stress and developmental competence-related genes were analysed in different stages of embryos. In RVCL medium, the cleavage rate of Ca2+ ionophore-treated oocytes (79.61 ± 0.86) was significantly (P < 0.05) higher than in ethanol (74.90 ± 1.51) or in the combination of both Ca2+ ionophore and ethanol. In mCR2a or EDM, hatched blastocyst production rate of Ca2+ ionophore-treated oocytes (8.33 ± 1.44) was significantly higher than in ethanol (6.46 ± 0.11) or in the combined treatment (6.70 ± 0.24). In ethanol, the cleavage, blastocyst and hatched blastocyst production rates in RVCL medium (74.90 ± 1.51, 18.30 ± 1.52 and 8.24 ± 0.15, respectively) were significantly higher than in EDM (67.81 ± 3.21, 14.59 ± 0.27 and 5.59 ± 0.42) or mCR2a medium (65.09 ± 1.57, 15.36 ± 0.52 and 6.46 ± 0.11). The expression of BAX, Oct-4 and GlUT1 transcripts increased gradually from 2-cell stage to blastocyst-stage embryos, whereas the transcript levels of Bcl-2 and MnSOD were significantly lower in blastocysts. In addition, different activation methods and culture media had little effect on the pattern of variation and relative abundance of the above genes in different stages of parthenogenetic activated goat embryos. In conclusion, Ca2+ ionophore as the activating agent, and RVCL as the culture medium are better than other tested options for development of parthenogenetic activated goat blastocysts.

REVIEW ON IN-VITRO AMEBOCYTE CULTURE–A LESSON LEARNED FROM PAST

2015 ◽  
Vol 77 (25) ◽  
Author(s):  
Hassan I. Sheikh ◽  
Akbar John, B. ◽  
Solachuddin J. A. Ichwan ◽  
Zaleha, K. ◽  
Kamaruzzaman, B. Y.
Keyword(s):  
Culture Media ◽  
Sole Source ◽  
Culture Conditions ◽  
Standard Test ◽  
Wild Stock ◽  
Implantable Medical Devices ◽  
Current Form ◽  
Horseshoe Crabs ◽  
A Cell

Limulus Amebocyte Lysate (LAL/TAL) assay is the only standard test approved by the Food and Drug Administration (FDA) to quantify bacterial endotoxin in injectable drugs and implantable medical devices. At present, horseshoe crabs are the sole source of LAL/TAL. Biomedical companies harvest and bleed horseshoe crabs which lead to ≤30% post bleeding mortality. The continuity of this practices will eventually deplete wild stock and threat horseshoe crab’s population. Though, many alternative biosensors were developed to quantify endotoxins, they are not without limitations and some of them even need LAL/TAL as source detectors. Hence, the LAL/TAL industry in its current form has ethical, ecological, commercial and technical issues that make it unideal standard test. An alternative method of culturing amebocyte in tissue culture medium has been addressed in literature since last 4 decades. This paper will address the issues in amebocyte culture in-vitro based on the published literatures. The paper will also suggest the best source of amebocyte cells (gill, gill flaps, blood), culture mode (monolayer or suspension), culture media (Grace's Insect Medium, Leibovitz’s L-15 Medium, Modified Essential medium, Shields and Sang insect medium, TNM-FH Medium, RPMI 1640 medium) and best culture conditions (pH, temperature, osmolarity). This review will also emphasize on key elements in establishing a cell line for the continuous harvesting of amebocyte in-vitro.

scholarly journals Beneficial effects of brain-derived neurotropic factor on in vitro maturation of porcine oocytes

Reproduction ◽  
2007 ◽  
Vol 134 (3) ◽  
pp. 405-414 ◽  
Author(s):  
Eugine Lee ◽  
Yeon Ik Jeong ◽  
Seon Mi Park ◽  
Jong Yun Lee ◽  
Ji Hye Kim ◽  
...  
Keyword(s):  
Culture Media ◽  
Polar Body ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Follicular Cells ◽  
Beneficial Effects ◽  
First Polar Body ◽  
Cytoplasmic Maturation ◽  
Neurotropic Factor

In an effort to improve the quality ofin vitroproduced porcine embryos, we investigated the effect of brain-derived neurotropic factor (BDNF), a neurotropin family member, onin vitromaturation (IVM) of porcine oocytes. The expression of BDNF and truncated isoforms of its receptor, tyrosine kinase B (TrkB), and p75 common neurotropin receptor was detected in both follicular cells and metaphase-I stage oocytes by RT-PCR. However, mRNA of full-length TrkB was not found in oocytes although it was detected in follicular cells. The expression pattern of BDNF and TrkB was confirmed by immunohistochemistry. Supplementation with BDNF (30 ng/ml) during IVM significantly (P< 0.05) increased the first polar body extrusion and glutathione levels in oocytes, whereas the effect of BDNF on nuclear maturation was diminished when gonadotropin and epidermal growth factor (EGF) were added to the culture media. However, treatment with BDNF (30 ng/ml) along with EGF (10 ng/ml) in the presence of gonadotropin significantly (P< 0.05) increased the developmental competence of oocytes to the blastocyst stage after bothin vitrofertilization (IVF; 29.1% when compared with control, 15.6%) and somatic cell nuclear transfer (SCNT; 13.6% when compared with control, 3%). This appeared to reflect a stimulatory interaction between BDNF and EGF to enhance the cytoplasmic maturation of oocytes to support successful preimplantation development. In conclusion, BDNFenhanced nuclearand cytoplasmic maturation of oocytes by autocrine and/or paracrine signals. Also, when used together with EGF, BDNF increased the developmental potency of embryos after IVF and SCNT, demonstrating an improvedin vitroproduction protocol for porcine oocytes.

86 IN VITRO-MATURED GILT OOCYTES CAN HAVE EQUAL OR BETTER DEVELOPMENTAL COMPETENCE THAN SOW OOCYTES WITH NEW MATURATION MEDIA

2017 ◽  
Vol 29 (1) ◽  
pp. 150 ◽  
Author(s):  
L. D. Spate ◽  
S. L. Murphy ◽  
J. A. Benne ◽  
A. Giraldo ◽  
D. Hylan ◽  
...  
Keyword(s):  
Growth Factor ◽  
Somatic Cell ◽  
Culture Media ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Blastocyst Development ◽  
Development In Vitro ◽  
Humidified Air

It has long been thought that oocytes obtained from sows yielded a higher level of developmental competence compared with oocytes obtained from prepubertal gilts. Because gilt-derived oocytes are more readily available to our laboratory and they are less developmentally competent, we hypothesised that by making alterations to our maturation system we could improve the developmental competence of the gilt-derived oocytes to that of their sow-derived counterparts. We performed 2 experiments that evaluated the ability of each source of oocyte to develop to the blastocyst stage, using altered maturation media. The first experiment focused on the developmental ability of each source of oocytes, through IVF and culture. The second experiment again focused on the developmental competence of each oocyte source but through somatic cell NT. For both experiments, the sow-derived oocytes were obtained from Desoto Biosciences and the gilt ovaries were collected from Smithfield Inc. in Milan, Missouri. Both sets of oocytes were in vitro matured in M199 supplemented with 0.57 mM cysteine, 5 μg mL−1 LH and FSH, and 10 ng mL−1 epidermal growth factor; however, the gilt derived media was altered to contain 40 ng mL−1 fibroblast growth factor 2 and 20 ng mL−1 insulin-like growth factor and leukemia inhibitory factor. Additionally, the maturation media for the sow-derived oocytes contained the addition of 5 μg mL−1 insulin and 10% follicular fluid. In the first experiment we performed IVF on oocytes from the 2 sources as per our laboratory standard IVF procedure, co-incubating the oocytes with 0.25 × 106 porcine semen for 4 h, followed by washing and moving the oocytes to MU2 culture media at 38.50°C in 5% CO2, humidified air overnight. After overnight culture the presumptive zygotes were transferred to the same conditions with 5% CO2, 5% O2, and 90% N2. After an additional 5 days, blastocyst development was assessed. The gilt oocytes yielded 39.3a ± 7.2% blastocyst, and the sow oocytes had a blastocyst rate of 24.9b ± 6.9%, with an n of 389 and 313, respectfully. Statistical analysis was performed by using Genmod in SAS 9.4. In the second experiment, using standard laboratory protocol for somatic cell NT, we activated both sets of oocytes with 200 μM thimerosal for 10 min followed by 30-min incubation with 4 mM dithiothreitol. The embryos were co-incubated for 15 h with 500 nM Scriptaid in the MU2 culture media in 5% CO2, humidified air; then these embryos were also moved to 5% CO2, 5% O2, and 90% N2 and cultured to Day 6. The sow oocytes produced a blastocyst percentage of 38.6%, and the gilt oocyte group had a blastocyst percentage of 43.5%, with an n of 290 and 285, respectfully. There was no difference statistically between these treatments. Both gilt and the sow oocyte sources have yielded live piglets at this time. We concluded that the maturation system used for our gilt-derived oocytes resulted in equal or better development in vitro compared with the sow-derived oocytes. Follow-up experiments evaluating in vivo development are needed for a complete comparison. This work was funded by Food for the 21st Century University of MO, and the NIH U42OD011140.

144 Sex ratio of in vitro-produced goat embryos

2019 ◽  
Vol 31 (1) ◽  
pp. 197 ◽  
Author(s):  
M. Stoltzfus ◽  
J. Wayman ◽  
R. Stilz ◽  
D. Bresnahan
Keyword(s):  
Sex Ratio ◽  
Dna Extraction ◽  
Culture Media ◽  
The United States ◽  
Blastocyst Stage ◽  
Culture Conditions ◽  
Pcr Analysis ◽  
Significant Difference ◽  
The Impact

Goats are important livestock species because they produce meat, milk, and fibre and are also easily maintainable on small farms. Although goats provide many products and consumption of goat meat is increasing in the United States, the industry lags compared with many species with regard to IVF techniques to enhance goat production. It has been demonstrated in other species that male IVF embryos tend to develop faster than those of females. This may be due to increased tolerance of male embryos to inadequate conditions, particularly, glucose concentrations in culture media. However, the sex ratio of goat embryos produced utilising IVF remains unknown. The aim of this study was to determine the sex ratio of goat embryos utilising a commercially available media suite (IVF Biosciences, Falmouth, UK). Oocytes were harvested from ovaries obtained from 2 local abattoirs and matured in vitro. Frozen sperm from 1 of 2 billy goats were randomly assigned for each round of IVF. Embryos were evaluated daily from Days (D) 6 through 9 of in vitro culture. On the day an embryo reached the expanded blastocyst stage, it was removed from culture and placed into DNA extraction buffer (PicoPureTM DNA Extraction Kit, Applied Biosystems, Waltham, MA, USA) and stored at −20 for PCR analysis, typically within one month of collection. In all unknown samples, positive male (sperm) and female (uterus) controls, the amelogenin gene was amplified and products were evaluated on a 1.5% agarose gel with ethidium bromide. Embryos with 2 bands (202 and 262bp) were classified as male, and those with 1 band (262bp) were classified as female. Embryos with no bands were not included in analysis. Embryos reached the expanded blastocyst stage on D6 (n=29), D7 (n=39), and D8/9 (n=35, combined for evaluation). A chi-squared analysis comparing the percentage of male and female embryos to the expected 50% was completed for each time point (D6, D7, D8/9), as well as overall ratios (D6-9). In total, 350 oocytes were utilised in 6 rounds of IVF resulting in a mean blastocyst rate of 32% (range 17-47%). There was no significant difference in the number of embryos that were male on D6 (55%) and D7 (46%). However, on D8/9 significantly fewer embryos were male (29% male; P=0.01). Overall, there was no significant difference (P=0.14) in the sex ratio, with 41% male and 59% female embryos. Our findings are somewhat consistent with other species, in that male goat embryos produced via IVF develop more quickly in culture conditions; however, female embryos were still able to tolerate culture conditions. Delayed blastocyst development may not necessarily be an indication of a reduced quality embryo but one that is slower to develop based on its sex. This could be due to expression of X-linked genes being unbalanced during pre-implantation embryo development stages and warrants further study. One influencer of sex ratio we are currently investigating is the impact of glucose during culture, to further understand metabolism in IVF embryos.

scholarly journals 51DEVELOPMENT OF BOVINE CLONES CONSTRUCTED WITH CYTOPLASM ORIGINATING FROM OOCYTES CULTURED IN RETINOL

2004 ◽  
Vol 16 (2) ◽  
pp. 147
Author(s):  
J.L. Lawrence ◽  
F.N. Schrick ◽  
J.D. Godkin ◽  
J.L. Edwards
Keyword(s):  
Granulosa Cells ◽  
Nuclear Transfer ◽  
Block Design ◽  
Polar Body ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Somatic Nucleus ◽  
Ovarian Granulosa Cells ◽  
Electrical Pulses

Incomplete reprogramming of a somatic nucleus by the oocyte cytoplasm may contribute in large part to inefficiencies of cloning procedures using somatic cell nuclear transfer. Predominant use of cytoplasts derived from in vitro-matured oocytes may further exacerbate problems. Addition of all-trans-retinol (Livingston TL et al. 2002 Biol. Reprod. 66, 104–105 abst) or 9-cis-retinoic acid (Duque P et al. 2002 Human Reprod. 17, 2706–2714) to culture medium improved developmental competence of oocytes to blastocyst stage. The objective of this study was to evaluate effects of retinol for improving developmental competence of cloned embryos constructed with retinol-treated cytoplasts. After removal from 3–8mm follicles, COC were matured in the presence of 0 (n=1005; diluent only) or 5μM all trans-retinol (n=1017). Beginning approximately 18h after placement into culture, oocytes with extruded polar bodies were enucleated of maternal chromatin. Ovarian/granulosa cells were aspirated from adult Jersey cows (n=2) using an ultrasound-guided transvaginal probe. Primary cell lines were established and, before nuclear transfer, cultured in the presence of 0.5% serum (5–8 days; passage =3). Ovarian/granulosa cells were fused with cytoplasts originating from control or retinol-treated oocytes using two electrical pulses of 2.2kVcm−1 for 20μs between 24–27h post-maturation (hpm). Cloned embryos were activated between 26.5 and 30hpm and then cultured in an atmosphere of 7% O2 and 5.5% CO2 in KSOMaa+BSA. Development of cloned embryos to morula and blastocyst stages was assessed on Days 6–7 post-activation. In 5 replicates, compact morulae and blastocysts were transferred to synchronous recipients. Establishment of pregnancy was confirmed 28 days post-estrus by presence of an embryonic heartbeat using ultrasound. With the exception of pregnancy, data were analyzed as a randomized block design using mixed models of SAS (2000) after testing for normality. Proportion of oocytes recovered after denuding (94.5 and 88.9%; SEM=2.2), those that had visibly lysed (6.4 and 7.3%; SEM=1.5), and extruded a polar body by 20hpm (61.7 and 62.5%; SEM=7.0) was similar for control and retinol-treated oocytes, respectively. In addition, ability of ovarian/granulosa cells to fuse with control or retinol-treated cytoplasts was similar (80.6 and 73.1%; SEM=4.5). Lysis of cytoplasts after electrical pulses (8.2 v. 13.6%; SEM=3.3) and activation (11.6 v. 5.0%; SEM=2.9) did not differ for control and retinol-treated cytoplasts. Development to morula and blastocyst stages was lower in cloned embryos constructed with retinol-treated cytoplasts (Table). However, ability of morulae and blastocysts to establish a pregnancy was comparable. One clone from each treatment developed to term and was born alive. Culture of oocytes in medium containing retinol during maturation did not improve developmental competence of clones.

scholarly journals Abilities of cumulus and granulosa cells to enhance the developmental competence of bovine oocytes during in vitro maturation period are promoted by midkine; a possible implication of its apoptosis suppressing effects

Reproduction ◽  
2006 ◽  
Vol 132 (4) ◽  
pp. 549-557 ◽  
Author(s):  
S Ikeda ◽  
K Saeki ◽  
H Imai ◽  
M Yamada
Keyword(s):  
Dna Fragmentation ◽  
Granulosa Cells ◽  
Cumulus Cell ◽  
Cumulus Cells ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Control Group ◽  
Blastocyst Development ◽  
Bovine Oocytes

We previously reported that when midkine (MK), a heparin-binding growth differentiation factor was used inin vitromaturation (IVM) culture of bovine cumulus-enclosed oocytes (CEOs), their developmental competence to the blastocyst stage afterin vitrofertilization (IVF) was enhanced and the effect of MK might be mediated by its action upon mural granulosa cells and cumulus cells that closely surround the oocyte. In the present study, when denuded oocytes (DOs) were matured in IVM medium with or without MK (200 ng/ml) in the presence or absence of isolated cumulus cell masses and subjected to IVF, the enhancing effects of MK on the developmental competence of DOs to the blastocyst stage after IVF were exerted only in the presence of cumulus cells. In addition, we prepared the conditioned media of granulosa cells cultured with or without 200 ng MK/ml (CMMK+ or CMMK− respectively) and examined their effects on the IVM of DOs in terms of their developmental competence to the blastocyst stage after IVF. The supplementation of CMMK+ into IVM medium at 40% (v/v) significantly enhanced the blastocyst development compared with the no additive control and the CMMK− supplemented groups. Furthermore, the effects of MK during IVM of bovine CEOs on the cumulus cell apoptosis were investigated. CEOs were cultured up to 24 h in IVM medium without (control) or with 200 ng MK/ml. The genomic DNA was extracted from CEOs at 0, 6, 12, 18 and 24 h of IVM and subjected to ligation-mediated PCR (LM-PCR) to detect the apoptotic internucleosomal DNA fragmentation. DNA fragmentation was scarcely detected at the start of IVM, whereas it increased time-dependently as the IVM culture progressed. The degree of the fragmentation was significantly lower in the MK-treatment group compared with the control group at 18 and 24 h of IVM. The apoptosis-suppressing effect of MK on cumulus cells was further confirmedin situby using TUNEL on CEOs. In conclusion, data from the present study further confirmed that MK enhances the developmental competence of bovine oocytes via cumulus and granulosa cells. It was also demonstrated that MK suppresses the apoptosis that occurs in cumulus cells during the period of IVM of bovine CEOs. The putative soluble factor(s) from cumulus cells was suggested from the experiment using CMMK+ . MK may promote the production of such factors in part by its anti-apoptotic effects on cumulus cells.

Supplementation of c-type natriuretic peptide during in vitro growth period benefits the development of murine preantral follicles

Zygote ◽  
2020 ◽  
pp. 1-5
Author(s):  
Li Ang ◽  
Cao Haixia ◽  
Li Hongxia ◽  
Li Ruijiao ◽  
Guo Xingping ◽  
...  
Keyword(s):  
Natriuretic Peptide ◽  
Granulosa Cells ◽  
Culture System ◽  
Early Stage ◽  
Developmental Competence ◽  
Control Group ◽  
Follicle Development ◽  
Control Groups ◽  
Preantral Follicles

Summary The present study investigated the effects of c-type natriuretic peptide (CNP) on the development of murine preantral follicles during in vitro growth (IVG). Preantral follicles isolated from ovaries of Kunming mice were cultured in vitro. In the culture system, CNP was supplemented in the experimental groups and omitted in the control groups. In Experiment 1, CNP was only supplemented at the early stage and follicle development was evaluated. In Experiments 2 and 3, CNP was supplemented during the whole period of in vitro culture. In Experiment 2, follicle development and oocyte maturity were evaluated. In Experiment 3, follicle development and embryo cleavage after in vitro fertilization (IVF) were assessed. The results showed that in the control groups in all three experiments, granulosa cells migrated from within the follicle and the follicles could not reach the antral stage. In the experimental groups in all three experiments, no migration of granulosa cells was observed and follicle development was assessed as attaining the antral stage, which was significantly superior to that of the control group (P < 0.0001). Oocyte meiotic arrest was effectively maintained, hence giving good developmental competence. In conclusion, CNP supplementation in the culture system during IVG benefited the development of murine preantral follicles.

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