We thank Dr. Naojiro Minami (Kyoto University) for providing the Oog1pro3.9 mice. This research was supported by the JSPS (KAKENHI # JP15H06275) and the Nitto Foundation.

Mice were housed in an environmentally controlled room at 23 &#177;1 &#176;C with a 12 h light/12 h dark cycle. Animal care protocols and experiments were conducted in accordance with the Guidelines for Animal Experimentation at Aichi Medical University and were approved by the incumbent Animal Care and Use Committee.
1. Preparation of Culture Medium and Dishes
<ol>
	<li>To prepare basic culture medium, add fetal bovine serum (FBS, 5% v/v), FSH (100 mIU/mL), LH (10 mU/mL), and penicillin-str...

<ol>
	<li>Myers, M., Britt, K. L., Wreford, N. G., Ebling, F. J., Kerr, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+quantifying+follicular+numbers+within+the+mouse+ovary.">Methods for quantifying follicular numbers within the mouse ovary.</a> Reproduction. 127 (5), 569-580 (2004).</li><li>Adams, G. P., Jaiswal, R., Singh, J., Malhi, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progress+in+understanding+ovarian+follicular+dynamics+in+cattle.">Progress in understanding ovarian follicular dynamics in cattle.</a> Theriogenology. 69 (1), 72-80 (2008).</li><li>Palma, G. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biology+and+biotechnology+of+follicle+development.">Biology and biotechnology of follicle development.</a> Sci World J. , (2012).</li><li>Knight, P. G., Glister, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TGF-beta+superfamily+members+and+ovarian+follicle+development.">TGF-beta superfamily members and ovarian follicle development.</a> Reproduction. 132 (2), 191-206 (2006).</li><li>Picton, H. M., Harris, S. E., Muruvi, W., Chambers, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+in+vitro+growth+and+maturation+of+follicles.">The in vitro growth and maturation of follicles.</a> Reproduction. 136 (6), 703-715 (2008).</li><li>Spears, N., de Bruin, J. P., Gosden, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+establishment+of+follicular+dominance+in+co-cultured+mouse+ovarian+follicles.">The establishment of follicular dominance in co-cultured mouse ovarian follicles.</a> J Reprod Fertil. 106 (1), 1-6 (1996).</li><li>Baker, S. J., Srsen, V., Lapping, R., Spears, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+effect+of+follicle-follicle+interactions+and+declining+follicle-stimulating+hormone+on+murine+follicle+health+in+vitro.">Combined effect of follicle-follicle interactions and declining follicle-stimulating hormone on murine follicle health in vitro.</a> Biol Reprod. 65 (4), 1304-1310 (2001).</li><li>Komatsu, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+Effect+of+Leukemia+Inhibitory+Factor+on+Follicular+Growth+in+Cultured+Murine+Ovarian+Tissue.">Analysis of the Effect of Leukemia Inhibitory Factor on Follicular Growth in Cultured Murine Ovarian Tissue.</a> Biol Reprod. 93 (1), 18 (2015).</li><li>Komatsu, K., Masubuchi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+concentration-dependent+effect+of+progesterone+on+follicle+growth+in+the+mouse+ovary.">The concentration-dependent effect of progesterone on follicle growth in the mouse ovary.</a> J Reprod Dev. 63 (3), 271-277 (2017).</li><li>Murase, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Follicle+dynamics:+visualization+and+analysis+of+follicle+growth+and+maturation+using+murine+ovarian+tissue+culture.">Follicle dynamics: visualization and analysis of follicle growth and maturation using murine ovarian tissue culture.</a> J Assist Reprod Genet. , 1-5 (2017).</li><li>Ishida, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+promoter+of+the+oocyte-specific+gene,+Oog1,+functions+in+both+male+and+female+meiotic+germ+cells+in+transgenic+mice.">The promoter of the oocyte-specific gene, Oog1, functions in both male and female meiotic germ cells in transgenic mice.</a> PLoS One. 8 (7), 68686 (2013).</li><li>Minami, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oogenesin+is+a+novel+mouse+protein+expressed+in+oocytes+and+early+cleavage-stage+embryos.">Oogenesin is a novel mouse protein expressed in oocytes and early cleavage-stage embryos.</a> Biol Reprod. 69 (5), 1736-1742 (2003).</li><li>Nilsson, E. E., Skinner, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+and+differentiation+factor-9+stimulates+progression+of+early+primary+but+not+primordial+rat+ovarian+follicle+development.">Growth and differentiation factor-9 stimulates progression of early primary but not primordial rat ovarian follicle development.</a> Biol Reprod. 67 (3), 1018-1024 (2002).</li><li>Nilsson, E. E., Kezele, P., Skinner, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leukemia+inhibitory+factor+(LIF)+promotes+the+primordial+to+primary+follicle+transition+in+rat+ovaries.">Leukemia inhibitory factor (LIF) promotes the primordial to primary follicle transition in rat ovaries.</a> Mol Cell Endocrinol. 188 (1-2), 65-73 (2002).</li><li>Nilsson, E. E., Skinner, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+morphogenetic+protein-4+acts+as+an+ovarian+follicle+survival+factor+and+promotes+primordial+follicle+development.">Bone morphogenetic protein-4 acts as an ovarian follicle survival factor and promotes primordial follicle development.</a> Biol Reprod. 69 (4), 1265-1272 (2003).</li><li>Nilsson, E. E., Skinner, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kit+ligand+and+basic+fibroblast+growth+factor+interactions+in+the+induction+of+ovarian+primordial+to+primary+follicle+transition.">Kit ligand and basic fibroblast growth factor interactions in the induction of ovarian primordial to primary follicle transition.</a> Mol Cell Endocrinol. 214 (1-2), 19-25 (2004).</li><li>Abe, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishment+of+conditional+reporter+mouse+lines+at+ROSA26+locus+for+live+cell+imaging.">Establishment of conditional reporter mouse lines at ROSA26 locus for live cell imaging.</a> Genesis. 49 (7), 579-590 (2011).</li><li>Lan, Z. J., Xu, X., Cooney, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+oocyte-specific+expression+of+Cre+recombinase+activity+in+GDF-9-iCre,+Zp3cre,+and+Msx2Cre+transgenic+mice.">Differential oocyte-specific expression of Cre recombinase activity in GDF-9-iCre, Zp3cre, and Msx2Cre transgenic mice.</a> Biol Reprod. 71 (5), 1469-1474 (2004).</li><li>Payer, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+stella-GFP+transgenic+mice:+a+novel+tool+to+study+germ+cell+development.">Generation of stella-GFP transgenic mice: a novel tool to study germ cell development.</a> Genesis. 44 (2), 75-83 (2006).</li><li>Ohinata, Y., Sano, M., Shigeta, M., Yamanaka, K., Saitou, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comprehensive,+non-invasive+visualization+of+primordial+germ+cell+development+in+mice+by+the+Prdm1-mVenus+and+Dppa3-ECFP+double+transgenic+reporter.">A comprehensive, non-invasive visualization of primordial germ cell development in mice by the Prdm1-mVenus and Dppa3-ECFP double transgenic reporter.</a> Reproduction. 136 (4), 503-514 (2008).</li></ol>

The authors have nothing to disclose.

In this study, we developed two new methods for studying follicle development in mouse ovaries. The first method involves culture of sliced ovarian adult mice tissues followed by analyses of follicle development, and the second involves the use of time-lapse imaging to visualize early follicle development during the gonadotropin-independent stage. Previously, we used the present ovary tissue culture method to assess the effect of leukemia inhibitory factor and progesterone on follicle development8...

Female mouse ovaries contain several thousand follicles1, and periodic ovulation matures approximately ten oocytes at each estrus cycle. Follicles are classified into several developmental stages: primordial, primary, secondary, antral, and Graafian follicles, depending on the form of the granulosa cellular layer surrounding each oocyte. Most primordial follicles are dormant, and some of them are activated and grow into primary follicles at each estrus cycle2. After the secondary follicular stage, follicle development is mainly regulated by gonadotropins, follicular stimulating hormone (FSH), and luteinizing hormone (LH). However, primordial and primary follicle development is independent of gonadotropin, and the regulatory mechanisms that govern these stages remain poorly inderstood3,4,5. In addition to growth factors and hormones, the primordial and primary follicle is regulated by the interactions among follicles6,7. Therefore, we performed analyses of follicle dynamics in mouse ovary tissues, and investigated the associated regulatory mechanisms using ovarian tissue cultures8,9,10.
Herein, we introduce two ovarian tissue culture model methods. The first is used to analyze follicle development by measurement of follicular areas, and the second is used to study the regulatory mechanism during early follicle development from primordial to secondary follicle stage with transgenic mice. For follicle development analysis, we mainly used ovaries of 4-week old female mice because they allow for easy visualization of follicles. To induce periodical ovulation and model in vivo follicle development, we reproduced LH surge and observed ovulation, follicle atresia, and secretion of estradiol under tissue culture conditions. Images of the cultured ovaries were captured, and the follicle development processes were analyzed by tracing changes in the follicular area. However, in bright field microscopy analyses, the distinction between primordial and early primary follicles was unclear. Thus, we developed a method to detect small follicles, and distinguish between the primordial, primary, and secondary follicle in cultured ovarian tissues using Oogenesin1 (Oog1) pro3.9 and R26-H2B-mCherry transgenic mice ovaries at days 0 and 4 after birth11. Oog1 expression is detectable in oocytes after entry into meiosis, and gradually increases with follicle development, allowing observation of the transition from primordial to primary follicles using time-lapse images of cultured ovary tissue11,12. Although morphological methods have been used to study factors that activate dormant primordial follicles13,14,15,16, physiological follicle development in ovaries is difficult to observe, and the effects of various factors remain uncharacterized. The present culture methods were designed to address this paucity in real time analyses of target factors.
In the present study, we tracked follicular development using a time-lapse imaging method and characterized the process of follicle development. Our novel methods offer an unprecedented tool for investigating the physiology of ovaries.

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	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:383px;">Follicle stimulating hormone from human pituitary</td>
			<td style="width:224px;">SIGMA</td>
			<td style="width:119px;">F4021</td>
			<td style="width:451px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lutenizing hormone from equine pituitary</td>
			<td>SIGMA</td>
			<td>L9773</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Penicillin-streptomycin solution</td>
			<td>Wako Pure Chemical Industries</td>
			<td>168-23191</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MEM a, GlutaMax, no nucleotides</td>
			<td>Thermo Fisher</td>
			<td>32561037</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Glass bottom dish</td>
			<td>MatTek</td>
			<td>P35G-0-10-C</td>
			<td>35mm dish, No. 0 coverslip, 10mm glass diameter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Millicell cell culture insert</td>
			<td>Merck Millipore</td>
			<td>PICM0RG50</td>
			<td>Diameter: 315 mm, pore size: 0.4 mm, material: hydrophilic PTTE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:383px;">3.5cm cell culture dishes</td>
			<td style="width:224px;">greiner bio-one</td>
			<td style="width:119px;">627160</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:383px;">50ml / centrifuge tube with triple seal cap</td>
			<td style="width:224px;">IWAKI</td>
			<td style="width:119px;">2345-050</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:383px;">Low-profile disposable blades 819</td>
			<td style="width:224px;">Leica</td>
			<td style="width:119px;">14035838925</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LSM 710</td>
			<td>Carl Zeiss</td>
			<td style="width:119px;"></td>
			<td>Confocal microscope</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CellVoyager, CV1000</td>
			<td>Yokogawa Electric Corporation</td>
			<td style="width:119px;"></td>
			<td>Time-lapse imaging</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BZ-X700</td>
			<td>KEYENCE</td>
			<td style="width:119px;"></td>
			<td>Time-lapse imaging</td>
		</tr>
	</tbody>
</table>

ovarian tissue culture to visualize phenomena in mouse ovary

Mammalian females periodically ovulate an almost constant number of oocytes during each estrus cycle. To sustain such regularity and periodicity, regulation occurs at the hypothalamic-pituitary-gonadal axis level and on developing follicles in the ovary. Despite active studies, follicle development mechanisms are not clear because of the several steps involved from the dormant primordial follicle activation to ovulation, and because of the regulation complexity that differs at each follicular stage. To investigate the mechanisms of follicle development, and the dynamics of follicles throughout the estrus cycle, we developed a mouse ovarian tissue culture model that can be used to observe follicle development using a microscope. Systematic follicle development, periodical ovulation, and follicle atresia can all be reproduced in the cultured ovary model, and the culture conditions can be experimentally modulated. Here, we demonstrate the usefulness of this method in the study of the regulatory mechanisms of follicle development and other ovarian phenomena.

Figure 1&#160;shows the protocol for changes in media during ovarian tissue culture. Following this program, 4-week-old ICR mice ovaries were cultured and imaged at 24-h intervals using confocal microscopy (Figure 2). During culture of ovary tissues for 3 weeks, most antral and secondary follicles were degenerated by follicle atresia and some were ovulated (Figure 2D and Tabl...

Watch this Scientific Journal Video about Ovarian Tissue Culture to Visualize Phenomena in Mouse Ovary at JoVE.com

Ovarian Tissue Culture to Visualize Phenomena in Mouse Ovary

Ovarian tissue cultures can be used as models of follicle development, ovulation, and follicle atresia and indicate regulatory mechanisms of dynamic ovarian processes.

Mammalian females periodically ovulate an almost constant number of oocytes during each estrus cycle. To sustain such regularity and periodicity, ...

This method can help answer key questions in the ovary research field about follicle development, follicle atresia and operation. The main advantage of this technique is that we can reproduce the ovarian phenomena under controlled culture conditions for the observation in real time. To prepare the ovaries from a four week old Institute of Cancer Research mouse for culture:Use scissors and tweezers to trim the surrounding tissue from the ovaries under a stereo microscope, and place the cleaned ovaries into a dish of fresh culture medium.When all of the ovaries have been trimmed, transfer the individual ovaries onto a piece of filter paper moistened with 37 degrees Celsius PBS, and use a microtome blade to slice each ovary into four pieces. Transfer the slices into a 3.5 centimeter dish of 37 degrees Celsius culture medium, and use a micropipette to add an about 0.5 micrometer droplet of culture medium onto one cell culture insert per ovarian tissue section. In a second 3.5 centimeter glass bottom cell culture dish containing one millimeter of medium:Using tweezers, transfer one tissue specimen into each droplet and place the plate in a cell culture incubator.Replace the supernatant in the dish with fresh 37 degrees Celsius culture medium every two days and treat the ovaries with 100 milliunits per milliliter of FSH and LH for 12 hours every fourth day. Begin imaging the cultured ovaries every 24 hours after one day of culture to allow sufficient follicle growth between imaging sessions;capturing images at 30 minute intervals using a time-lapse imaging system under the appropriate experimental conditions. To analyze ovarian follicle development:Open the images in ImageJ and open the analyze menu to select set scale.Enter the side lengths of the captured images and the corresponding numbers of pixels in the known distance and distance in pixels fields, respectively. Then, use the free-hand tool to outline the follicles and click measure. During a three week ovarian tissue slice culture period, most antral and secondary follicles are degenerated by follicle atresia, and some are ovulated.Some follicles develop in groups during each LH surge cycle. While the timing of ovulation and the number of ovulated oocytes differs between mouse ovaries, ovulation from cultured ovaries predominantly occurs within 48 hours of each LH surge. Note that not all ovulated oocytes release first polar bodies after ovulation.Primordial and primary follicles are present simultaneously in postnatal day four mouse ovaries. Whereas, only primordial follicles are present in postnatal day zero ovaries. However, primary follicles become detectable in cultured postnatal day zero ovaries after 30 to 40 hours of culture as demonstrated.Primordial and primary follicles can also be distinguished in the cultured ovaries isolated from mCherry transgenic animals by the mCherry positive nuclei of granulosa cells;allowing the tracking of the follicle stages in the ovary slice cultures. I hope that this technique paves the way for researchers in the field of reproductive technology to explore new techniques for fertility treatment.

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Developmental Biology

13.5K visualizações.  Aichi Medical University. This method can help answer key questions in the ovary research field about follicle development, follicle atresia and operation. The main advantage of this technique is that we can reproduce the ovarian phenomena under controlled culture conditions for the observation in real time. To prepare the ovaries from a four week old Institute of Cancer Research mouse for culture:Use scissors and tweezers to trim the surrounding tissue from the ovaries under a stereo microscope, and place the cleaned...