Mouse Oocyte Mitogenic Activity Is Developmentally Coordinated throughout Folliculogenesis and Meiotic Maturation

The Reproductive Medicine Unit, Adelaide University, Adelaide, 5011, Australia.
Developmental Biology (Impact Factor: 3.55). 01/2002; 240(1):289-98. DOI: 10.1006/dbio.2001.0451
Source: PubMed


Oocytes secrete soluble factors that regulate the growth and differentiation of follicular cells, including maintenance of the distinctive cumulus cell phenotype. This study determines whether the mitogenic activity of oocytes is developmentally regulated and examines the responsiveness of follicular cells to oocytes at different stages of follicular development. Prepubertal SV129 mice of varying ages were primed with 5 IU equine chorionic gonadotropin (eCG) and oocytes/zygotes collected either 46 h post-eCG (immature oocytes), 12 h after administration of 5 IU human CG (hCG; ovulated ova), or 12 h post-hCG and mating (zygotes). Mural granulosa cells (MGC) from antral follicles and GC from preantral follicles were cultured +/- denuded oocytes (DO) for 18 h, followed by a 6-h pulse of [(3)H]thymidine as an indicator of cellular DNA synthesis. Coculturing MGC with meiotically maturing oocytes led to a dose-dependent increase in [(3)H]thymidine incorporation (20-fold above control levels at 0.5 DO/microl). However, [(3)H] counts remained unchanged from control levels when cultured with meiotically incompetent DO from 11- to 15-day-old mice (3% germinal vesicle breakdown; GVB), irrespective of dose of DO or developmental status of GC (MGC or preantral GC). In some treatments, spontaneous meiotic resumption of competent oocytes was prevented by culturing with 5 microM milrinone, a selective inhibitor of oocyte-specific cyclic nucleotide phosphodiesterase. The mitogenic capacity of oocytes was found to decline during and after oocyte maturation. [(3)H]Thymidine incorporation in MGC was highest (11-fold above controls) when cultured with meiotically inhibited (milrinone-treated) GV DO, stimulated 5.5-fold by culture with maturing oocytes, 3-fold with ovulated ova, and unstimulated by zygotes. [(3)H]Thymidine incorporation in MGC was not altered by the dose of milrinone, either in the presence or absence of DO. Metaphase I marked the beginning of the decline in the capacity of oocytes to promote MGC DNA synthesis. These results demonstrate that the capacity of oocytes to promote proliferation of granulosa cells follows a developmental program, closely linked to oocyte meiotic status, increasing with the acquisition of meiotic competence and declining during and after oocyte maturation.

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Available from: Robert B Gilchrist, Aug 07, 2014
    • "In every trial of the present study, a ratio of 0.16 DO/μL and 0.36 DO/μL was applied. These ratios are higher than 0.128 DO/μL, which was described in two previous studies (Gilchrist et al. 2001, 2006), and are within the range of 0.1 DO/μL to 1.0 DO/μL as described by Hussein et al. (2005). Based on these findings in the literature, the applied number of oocytes/μL in the present study is believed to be sufficient to reveal any possible effects of OSFs. "
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    ABSTRACT: Co-culture of cumulus-oocyte complexes (COCs) with denuded oocytes (DOs) during in vitro maturation (IVM) was reported to improve the developmental competence of oocytes via oocyte-secreted factors in cattle. The aim of the present study was to investigate if addition of DOs during IVM can improve in vitro fertilization (IVF) and in vitro culture (IVC) results for oocytes in a defined in vitro production system in pigs. The maturation medium was porcine oocyte medium supplemented with gonadotropins, dbcAMP and β-mercaptoethanol. Cumulus-oocyte complexes were matured without DOs or with DOs in different ratios (9 COC, 9 COC+16 DO and 9 COC+36 DO). Consequently; oocytes were subjected to IVF as intact COCs or after denudation to examine if DO addition during IVM would affect cumulus or oocyte properties. After fertilization, penetration and normal fertilization rates of zygotes were not different between all tested groups irrespective of denudation before IVF. When zygotes were cultured for 6 days, no difference could be observed between all treatment groups in cleavage rate, blastocyst rate and cell number per blastocyst. In conclusion, irrespective of the ratio, co-culture with DOs during IVM did not improve fertilization parameters and embryo development of cumulus-enclosed porcine oocytes in a defined system. © 2015 Japanese Society of Animal Science.
    Animal Science Journal 08/2015; DOI:10.1111/asj.12459 · 0.96 Impact Factor
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    • "There are various paracrine factors involved in regulating follicle growth (McGrath et al., 1995; Dube et al., 1998; Gilchrist et al., 2001; Markstrom et al., 2002). Moreover, it has been suggested that the growth and maturation of intrafollicular oocytes in preantral follicles are significantly influenced by cell to cell interaction between oocytes and surrounding follicular cells (granulosa and theca cells) through paracrine methods (Eppig et al., 2002). "
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    ABSTRACT: This study was conducted to improve the yield of mature oocytes from in vitro-culture of ovarian primary follicles by optimizing follicle retrieval from neonatal mice of different ages. Primary follicles of 75 to 99 μm in diameter were collected daily from 7- to 14-day-old neonatal mice, and subsequently cultured in α-MEM medium. Number of primary follicles isolated, growth of the follicle during in vitro-culture and maturation of intrafollicular oocytes were monitored. Overall, mean number of preantral follicles per animal was improved from 10.7 to 88.7 as the age of follicle donors was increased from 7 to 14-day-old. Number of primary follicles was increased gradually up to 11-day-old (35.7 follicle per an animal), then reduced to 29 in 14-day-old (p = 0.0013). More follicles retrieved from 10-day-old or 11-day-old females maintained their morphological normality at the end of primary culture than the follicles retrieved from 9-day-old. Of those cultured, primary follicles retrieved from 11-day-old mice yielded largest larger number of early secondary follicles than the follicles retrieved from in the other ages (39 vs. 13 to 29%). More than 3.3-times increase (0.86 to 2.86; p<0.05) in an average number of mature oocytes per animal was observed in the group of 11-day-old, compared with 9-day-old. However, no difference was found in the percentage of primary follicles developing into the pseudoantral stage (21 to 30%; p = 0.5222) and in the percentage of oocytes mucified (32 to 39%; p = 0.5792). In conclusion, a positive correlation between retrieval time and follicle growth was detected, which influences the efficiency to derive mature oocytes by follicle culture.
    Asian Australasian Journal of Animal Sciences 05/2012; 25(5):629-34. DOI:10.5713/ajas.2010.10249 · 0.54 Impact Factor
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    • "Stimulation of Ccnd2 (Gilchrist et al., 2006) Stimulation of GC/CC DNA synthesis, cell number or follicle growth (Vanderhyden et al., 1992; Lanuza et al., 1998; Li et al., 2000; Gilchrist et al., 2001; Eppig et al., 2002; Brankin et al., 2003; Gilchrist et al., 2003b; Glister et al., 2003; Gilchrist et al., 2004; Hickey et al., 2005; Gilchrist et al., 2006) Interaction of OSFs with IGF-I (Lanuza et al., 1998; Li et al., 2000; Brankin et al., 2003; Gilchrist et al., 2003b; Hickey et al., 2005) Stimulation of CC Ar (Diaz et al., 2007) "
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    ABSTRACT: This chapter contains sections titled: Introduction Historical Background Localization and Specificity Structure and Genetic Diversity of Gdf9 and Bmp15 Signalling Mechanisms of Gdf9 and Bmp15 Roles of Oocyte-Secreted Factors Manipulation and Use in Reproductive Technologies Concluding Remarks References
    01/2012: pages (in press); Wiley Blackwell Publishing.
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