Name: accurate follicle enumeration in adult mouse ovaries
Uploaded: 2020-10-16T15:00:00
Description: Watch this Scientific Journal Video about Accurate Follicle Enumeration in Adult Mouse Ovaries at JoVE.com

This work was made possible through Victorian State Government Operational Infrastructure Support and Australian Government NHMRC IRIISS and supported by funding from National Health and Medical Research Council (ALW #1120300) and Australian Research Council (KJH #FT190100265). The authors would like to acknowledge the technical support of the Monash Animal Research Platform, Monash Histology Platform and Monash Micro Imaging facility.

Ovaries were collected from female C57BL6J mice. All animal procedures and experiments were performed in accordance with the NHMRC Australian Code of Practice for the Care and Use of Animals and approved by the Monash Animal Research Platform Animal Ethics Committee.
NOTE: A chemotherapy agent shown to deplete primordial follicle oocytes, as determined using stereology11 and direct counts12,13 was used in this r...

<ol>
	<li>Stringer, J. M., Winship, A., Liew, S. H., Hutt, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+capacity+of+oocytes+for+DNA+repair.">The capacity of oocytes for DNA repair.</a> Cellular and Molecular Life Sciences. 75 (15), 2777-2792 (2018).</li><li>Winship, A. L., Stringer, J. M., Liew, S. H., Hutt, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+importance+of+DNA+repair+for+maintaining+oocyte+quality+in+response+to+anti-cancer+treatments,+environmental+toxins+and+maternal+ageing.">The importance of DNA repair for maintaining oocyte quality in response to anti-cancer treatments, environmental toxins and maternal ageing.</a> Human Reproduction Update. 24 (2), 119-134 (2018).</li><li>Broer, S. L., Broekmans, F. J., Laven, J. S., Fauser, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anti-Mullerian+hormone:+ovarian+reserve+testing+and+its+potential+clinical+implications.">Anti-Mullerian hormone: ovarian reserve testing and its potential clinical implications.</a> Human Reproduction Update. 20 (5), 688-701 (2014).</li><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>Boyce, R. W., Dorph-Petersen, K. A., Lyck, L., Gundersen, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design-based+stereology:+introduction+to+basic+concepts+and+practical+approaches+for+estimation+of+cell+number.">Design-based stereology: introduction to basic concepts and practical approaches for estimation of cell number.</a> Toxicologic Pathology. 38 (7), 1011-1025 (2010).</li><li>Ristic, 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=Maternal+dexamethasone+treatment+reduces+ovarian+follicle+number+in+neonatal+rat+offspring.">Maternal dexamethasone treatment reduces ovarian follicle number in neonatal rat offspring.</a> Journal of Microscopy. 232 (3), 549-557 (2008).</li><li>Soleimani Mehranjani, M., Mansoori, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereological+study+on+the+effect+of+vitamin+C+in+preventing+the+adverse+effects+of+bisphenol+A+on+rat+ovary.">Stereological study on the effect of vitamin C in preventing the adverse effects of bisphenol A on rat ovary.</a> International Journal of Reproductive Biomedicine (Yazd). 14 (6), 403-410 (2016).</li><li>Brown, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bias+in+image+analysis+and+its+solution:+unbiased+stereology.">Bias in image analysis and its solution: unbiased stereology.</a> Journal of Toxicologic Pathology. 30 (3), 183-191 (2017).</li><li>Hasselholt, S., Lykkesfeldt, J., Overgaard Larsen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thick+methacrylate+sections+devoid+of+lost+caps+simplify+stereological+quantifications+based+on+the+optical+fractionator+design.">Thick methacrylate sections devoid of lost caps simplify stereological quantifications based on the optical fractionator design.</a> Anatomical Record (Hoboken). 298 (12), 2141-2150 (2015).</li><li>Tilly, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ovarian+follicle+counts--not+as+simple+as+1,+2,+3.">Ovarian follicle counts--not as simple as 1, 2, 3.</a> Reproductive Biology and Endocrinology. 1, 11 (2003).</li><li>Nguyen, Q. 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=Loss+of+PUMA+protects+the+ovarian+reserve+during+DNA-damaging+chemotherapy+and+preserves+fertility.">Loss of PUMA protects the ovarian reserve during DNA-damaging chemotherapy and preserves fertility.</a> Cell Death and Disease. 9 (6), 618 (2018).</li><li>Meirow, D., Assad, G., Dor, J., Rabinovici, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+GnRH+antagonist+cetrorelix+reduces+cyclophosphamide-induced+ovarian+follicular+destruction+in+mice.">The GnRH antagonist cetrorelix reduces cyclophosphamide-induced ovarian follicular destruction in mice.</a> Human Reproduction. 19 (6), 1294-1299 (2004).</li><li>Winship, A. L., 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+PARP+inhibitor,+olaparib,+depletes+the+ovarian+reserve+in+mice:+implications+for+fertility+preservation.">The PARP inhibitor, olaparib, depletes the ovarian reserve in mice: implications for fertility preservation.</a> Human Reproduction. , (2020).</li><li>Meirow, D., Lewis, H., Nugent, D., Epstein, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subclinical+depletion+of+primordial+follicular+reserve+in+mice+treated+with+cyclophosphamide:+clinical+importance+and+proposed+accurate+investigative+tool.">Subclinical depletion of primordial follicular reserve in mice treated with cyclophosphamide: clinical importance and proposed accurate investigative tool.</a> Human Reproduction. 14 (7), 1903-1907 (1999).</li><li>Nguyen, Q. 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=Cisplatin-+and+cyclophosphamide-induced+primordial+follicle+depletion+is+caused+by+direct+damage+to+oocytes.">Cisplatin- and cyclophosphamide-induced primordial follicle depletion is caused by direct damage to oocytes.</a> Molecular Human Reproduction. , (2019).</li><li>Gundersen, H. J., Jensen, E. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+efficiency+of+systematic+sampling+in+stereology+and+its+prediction.">The efficiency of systematic sampling in stereology and its prediction.</a> Journal of Microscopy. 147, 229-263 (1987).</li><li>Olesen, M. V., Needham, E. K., Pakkenberg, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Optical+Fractionator+Technique+to+Estimate+Cell+Numbers+in+a+Rat+Model+of+Electroconvulsive+Therapy.">The Optical Fractionator Technique to Estimate Cell Numbers in a Rat Model of Electroconvulsive Therapy.</a> Journal of Visualized Experiments. (125), e55737 (2017).</li><li>Findlay, J. K., Hutt, K. J., Hickey, M., Anderson, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+Is+the+Number+of+Primordial+Follicles+in+the+Ovarian+Reserve+Established.">How Is the Number of Primordial Follicles in the Ovarian Reserve Established.</a> Biology of Reproduction. 93 (5), 111 (2015).</li><li>Omari, S., 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=Mcl-1+is+a+key+regulator+of+the+ovarian+reserve.">Mcl-1 is a key regulator of the ovarian reserve.</a> Cell Death and Disease. 6, 1755 (2015).</li><li>Winship, A. L., Bakai, M., Sarma, U., Liew, S. H., Hutt, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dacarbazine+depletes+the+ovarian+reserve+in+mice+and+depletion+is+enhanced+with+age.">Dacarbazine depletes the ovarian reserve in mice and depletion is enhanced with age.</a> Scientific Reports. 8 (1), 6516 (2018).</li><li>Miller, P. B., Charleston, J. S., Battaglia, D. E., Klein, N. A., Soules, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+accurate,+simple+method+for+unbiased+determination+of+primordial+follicle+number+in+the+primate+ovary.">An accurate, simple method for unbiased determination of primordial follicle number in the primate ovary.</a> Biology of Reproduction. 56 (4), 909-915 (1997).</li><li>Miller, P. B., Charleston, J. S., Battaglia, D. E., Klein, N. A., Soules, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphometric+analysis+of+primordial+follicle+number+in+pigtailed+monkey+ovaries:+symmetry+and+relationship+with+age.">Morphometric analysis of primordial follicle number in pigtailed monkey ovaries: symmetry and relationship with age.</a> Biology of Reproduction. 61 (2), 553-556 (1999).</li><li>Charleston, J. S., 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=Estimating+human+ovarian+non-growing+follicle+number:+the+application+of+modern+stereology+techniques+to+an+old+problem.">Estimating human ovarian non-growing follicle number: the application of modern stereology techniques to an old problem.</a> Human Reproduction. 22 (8), 2103-2110 (2007).</li><li>Hansen, K. R., Craig, L. B., Zavy, M. T., Klein, N. A., Soules, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ovarian+primordial+and+nongrowing+follicle+counts+according+to+the+Stages+of+Reproductive+Aging+Workshop+(STRAW)+staging+system.">Ovarian primordial and nongrowing follicle counts according to the Stages of Reproductive Aging Workshop (STRAW) staging system.</a> Menopause. 19 (2), 164-171 (2012).</li><li>Hansen, K. R., 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=A+new+model+of+reproductive+aging:+the+decline+in+ovarian+non-growing+follicle+number+from+birth+to+menopause.">A new model of reproductive aging: the decline in ovarian non-growing follicle number from birth to menopause.</a> Human Reproduction. 23 (3), 699-708 (2008).</li><li>Sonigo, C., 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=High-throughput+ovarian+follicle+counting+by+an+innovative+deep+learning+approach.">High-throughput ovarian follicle counting by an innovative deep learning approach.</a> Scientific Reports. 8 (1), 13499 (2018).</li><li>McKey, J., Cameron, L. A., Lewis, D., Batchvarov, I. S., Capel, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+iDISCO+and+CUBIC+tissue+clearing+and+lightsheet+microscopy+for+in+toto+analysis+of+the+adult+mouse+ovarydagger.">Combined iDISCO and CUBIC tissue clearing and lightsheet microscopy for in toto analysis of the adult mouse ovarydagger.</a> Biology of Reproduction. 102 (5), 1080-1089 (2020).</li><li>Kagami, K., Shinmyo, Y., Ono, M., Kawasaki, H., Fujiwara, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+evaluation+of+murine+ovarian+follicles+using+a+modified+CUBIC+tissue+clearing+method.">Three-dimensional evaluation of murine ovarian follicles using a modified CUBIC tissue clearing method.</a> Reproductive Biology and Endocrinology. 16 (1), 72 (2018).</li></ol>

This article provides a step-by-step protocol for the gold standard technique for enumerating mouse primordial follicles, stereology, and the more commonly employed method of direct follicle counting. Chemotherapy treatment was used to compare and contrast the results obtained from these two different methods within the left and right ovary from the same animal. Both methods revealed high inter-animal variability in primordial follicle numbers. A significant depletion of the ovarian reserve was recorded using stereology,...

The immature, meiotically-arrested oocytes stored within primordial follicles in the ovary are the storage unit for the female germline and comprise an individual&#8217;s lifetime ovarian reserve. Primordial follicle numbers decline naturally with age1, or alternatively, can be prematurely depleted following exposure to exogenous chemicals, including some pharmaceuticals and environmental toxicants in air, food and water2. Given that the primordial follicle number is finite, the quantity and quality of follicles present within the ovary largely determine female fertility and offspring health. Thus, accurate quantification of primordial follicle number in women is essential for evaluating the off-target impacts of exogenous insults on the ovarian reserve.
In women, analysis of the whole ovary is generally not possible, thus non-invasive surrogate measures of the ovarian reserve must be utilized in a clinical setting. Anti-M&#971;llerian hormone (AMH) is the most widely used surrogate biomarker clinically3. Serum AMH levels are often measured in women of advanced maternal age, or before and after cancer treatment, such as chemotherapy. However, AMH is produced by growing follicles and not by primordial follicles, and thus, serum levels do not inform on absolute primordial follicle number.
With the absence of methods to accurately determine primordial follicle number in women in situ, counting ovarian follicles in small animal models, such as rodents, remains an essential research tool to assess the degree by which exogenous insults impact on primordial follicles and thus, fertility. Unfortunately though, reports throughout the literature of primordial follicle numbers in rodent models are highly variable4. A major reason for this is widely reported technical differences in the counting method employed. Predominately, there are two different techniques described in the literature for enumerating primordial follicles in mice. These include stereology, which employs the fractionator optical dissector method, and direct follicle counts.
Stereology is widely regarded the gold standard as it uses systematic uniform random sampling5, making it the most accurate method of quantifying primordial follicle number in whole mouse, or rat ovaries4,6,7. Stereology is unbiased, as it accounts for the three-dimensional structure of the object of interest8. Using an optical dissector/fractionator method, three levels of sampling are applied to quantify primordial follicles using thick tissue sections (e.g., 20 &#181;m) within a known fraction of the total mouse ovary. Firstly, the sampling interval is chosen (e.g., every 3rd section) at a random start (sampling fraction 1, f1)4. Sections are then sampled in a systematic, uniform manner from this point through the whole ovary. Then, an unbiased counting frame is superimposed over the ovarian section and progressively moved along a defined, randomized counting grid (sampling fraction 2, f2)8. Lastly, a known fraction of the section thickness is optically sampled (e.g., 10 &#181;m) and follicles within this area are counted (sampling fraction 3, f3)4. The raw follicle number is multiplied by the inverse of these sampling fractions to obtain the final value. This method requires expert training and equipment, including a microscope with a motorized stage driven by stereological software. Tissues should be preserved in a specialized Bouin&#8217;s fixative, and embedded in glycolmethacrylate resin to allow for thick tissue sections to be cut using a glycolmethacrylate resin microtome with a glass knife. This method is designed to account for tissue shrinkage and deformation, to best preserve the three-dimensional morphological structure of the ovary and follicles9.
Direct follicle counting is the most frequently used method for counting follicles10. More common fixatives (i.e., formalin) can be used, followed by paraffin wax embedding and exhaustive serial sectioning using a standard microtome at a thickness of between 4-6 &#181;m. Follicles are systematically counted in the entire tissue section at a defined interval, and then multiplied by the inverse of the sampling interval to obtain the total follicle estimate. This method is quick, easy, can be performed using archived tissues, and prepared using standard histological techniques. It requires only a light microscope with standard imaging capabilities. However, despite these advantages, direct follicle counting lacks the accuracy and strict counting parameters of stereology, making it more prone to investigator bias. Additionally, tissues may undergo shrinkage and deformation during processing, disrupting the integrity and morphology of the ovary and thus making follicle classification and quantification difficult.
The aim of this article is to describe two commonly-used methods to quantitatively assess primordial follicle number in mouse ovaries: stereology and direct follicle counting. We will provide detailed protocols for these two methods and highlight some of their strengths and weaknesses, in order to enhance reproducibility in our field and allow researchers to make an informed decision of the most appropriate counting method for their studies.

<table>
	<tbody>
		<tr>
			<td>1-Butanol (HPLC)</td>
			<td>Fisher Chemical</td>
			<td>#A383-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Acid alcohol</td>
			<td>Amber Scientific</td>
			<td>#ACDL</td>
			<td></td>
		</tr>
		<tr>
			<td>Bouin&#8217;s fixative</td>
			<td>Sigma-Aldrich</td>
			<td>#HT10132</td>
			<td>Picric acid 0.9% (w/v), formaldehyde 9% (v/v), acetic acid 5% (w/v)</td>
		</tr>
		<tr>
			<td>Cyclophosphamide</td>
			<td>Sigma-Aldrich</td>
			<td>#C0768-5G</td>
			<td></td>
		</tr>
		<tr>
			<td>Dibutylphthalate Polystyrene Xylene (DPX)</td>
			<td>Sigma-Aldrich</td>
			<td>#06522</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Amber Scientific</td>
			<td>#ETH</td>
			<td>Ethanol 100%</td>
		</tr>
		<tr>
			<td>Micro Feather opthalmic scalpel with aluminium handle</td>
			<td>Designs for Vision</td>
			<td>#FEA-745-SR</td>
			<td>Feather blade for dissections (seen in Figure 1)</td>
		</tr>
		<tr>
			<td>Formalin fixative</td>
			<td>Australian Biostain</td>
			<td>#ANBFC</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass coverslip</td>
			<td>Thermo Scientific</td>
			<td>#MENCS22501GP</td>
			<td>22 mm x 50 mm</td>
		</tr>
		<tr>
			<td>Glycomethacrylate resin RM2165 microtome</td>
			<td>Leica Microsystems</td>
			<td>#RM2165</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycolmethacrylate DPX</td>
			<td>*made in house</td>
			<td></td>
			<td>*Mix 1.5 L Xylene; 800 g polystyrene pellets; 100mL Dibutyl phthalate for 3 weeks</td>
		</tr>
		<tr>
			<td>Histolene</td>
			<td>Trajan</td>
			<td>#11031</td>
			<td></td>
		</tr>
		<tr>
			<td>Mayer&#8217;s haematoxylin</td>
			<td>Amber Scientific</td>
			<td>#MH</td>
			<td></td>
		</tr>
		<tr>
			<td>Olympus BX50 microscope</td>
			<td>Olympus</td>
			<td>#BX50</td>
			<td>Brightfield microscope fitted with 10x dry &#38; 100x oil immersion objective (numerical aperture 1.3)</td>
		</tr>
		<tr>
			<td>Olympus immersion oil type-F</td>
			<td>Olympus</td>
			<td>#IMMOIL-F30CC</td>
			<td></td>
		</tr>
		<tr>
			<td>Olympus TH4-200 light source</td>
			<td>Olympus</td>
			<td>#TH4-200</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraffin wax</td>
			<td>Sigma-Aldrich</td>
			<td>#03987</td>
			<td></td>
		</tr>
		<tr>
			<td>Periodic acid</td>
			<td>Trajan</td>
			<td>#PERI1%</td>
			<td>Periodic acid 1%</td>
		</tr>
		<tr>
			<td>Rotary Microtome CUT 4060</td>
			<td>MicroTec</td>
			<td>#4060R/F</td>
			<td>Used to cut paraffin sections</td>
		</tr>
		<tr>
			<td>Schiff&#8217;s reagent</td>
			<td>Trajan</td>
			<td>#SCHF</td>
			<td></td>
		</tr>
		<tr>
			<td>Scott&#39;s tap water</td>
			<td>Amber Scientific</td>
			<td>#SCOT</td>
			<td>Potassium carbonate, magnesium sulphate, water</td>
		</tr>
		<tr>
			<td>StereoInvestigator Stereological System</td>
			<td>MBF Bioscience</td>
			<td></td>
			<td>Includes StereoInvestigator software, multi-control unit, automatic stage and joystick</td>
		</tr>
		<tr>
			<td>Superfrost microscope slides</td>
			<td>Thermo Scientific</td>
			<td>#MENSF41296SP</td>
			<td>1 mm, 72 pcs</td>
		</tr>
		<tr>
			<td>Technovit 7100 Plastic embedding system</td>
			<td>Emgrid Australia</td>
			<td>#64709003</td>
			<td>500 mL/5 x 1 g/40 mL</td>
		</tr>
		<tr>
			<td>Technovit 3040 yellow</td>
			<td>Emgrid Australia</td>
			<td>#64708805</td>
			<td>100 g/80 mL</td>
		</tr>
	</tbody>
</table>

accurate follicle enumeration in adult mouse ovaries

Sexually reproducing female mammals are born with their entire lifetime supply of oocytes. Immature, quiescent oocytes are found within primordial follicles, the storage unit of the female germline. They are non-renewable, thus their number at birth and subsequent rate of loss largely dictates the female fertile lifespan. Accurate quantification of primordial follicle numbers in women and animals is essential for determining the impact of medicines and toxicants on the ovarian reserve. It is also necessary for evaluating the need for, and success of, existing and emerging fertility preservation techniques. Currently, no methods exist to accurately measure the number of primordial follicles comprising the ovarian reserve in women. Furthermore, obtaining ovarian tissue from large animals or endangered species for experimentation is often not feasible. Thus, mice have become an essential model for such studies, and the ability to evaluate primordial follicle numbers in whole mouse ovaries is a critical tool. However, reports of absolute follicle numbers in mouse ovaries in the literature are highly variable, making it difficult to compare and/or replicate data. This is due to a number of factors including strain, age, treatment groups, as well as technical differences in the methods of counting employed. In this article, we provide a step-by-step instructional guide for preparing histological sections and counting primordial follicles in mouse ovaries using two different methods: [1] stereology, which relies on the fractionator/optical dissector technique; and [2] the direct count technique. Some of the key advantages and drawbacks of each method will be highlighted so that reproducibility can be improved in the field and to enable researchers to select the most appropriate method for their studies.

A well-characterized model of follicle depletion was used, whereby young adult female mice were administered a single dose of cyclophosphamide chemotherapy, or saline vehicle control (n=5/group) and both ovaries were harvested from each animal after 48 hours. One ovary per animal was prepared as described in Step 1 for each of the two methods: stereology or direct counts. The left and right ovary from each animal was randomly assigned to each group. These data show that when using stereology, a significant depletion of m...

Watch this Scientific Journal Video about Accurate Follicle Enumeration in Adult Mouse Ovaries at JoVE.com

Accurate Follicle Enumeration in Adult Mouse Ovaries

Here, we describe, compare, and contrast two different techniques for accurate follicle counting of fixed mouse ovarian tissues.

Sexually reproducing female mammals are born with their entire lifetime supply of oocytes. Immature, quiescent oocytes are found within primordial ...

Research

JoVE Journal

Developmental Biology

Culture and Co-Culture of Mouse Ovaries and Ovarian Follicles

The mammalian ovary is composed of ovarian follicles, each follicle consisting of a single oocyte surrounded by somatic granulosa cells, enclosed together ...

Accurate and Phenol Free DNA Sexing of Day 30 Porcine Embryos by PCR

Research into prenatal programming in the pig has shown that the sex of the developing embryo or fetus can influence the developmental outcome. Therefore, ...

Isolating Hair Follicle Stem Cells and Epidermal Keratinocytes from Dorsal Mouse Skin

The hair follicle (HF) is an ideal system for studying the biology and regulation of adult stem cells (SCs). This dynamic mini organ is replenished by ...

Dissection and Immunofluorescent Staining of Mushroom Body and Photoreceptor Neurons in Adult Drosophila melanogaster Brains

Dissection and Immunofluorescent Staining of Mushroom Body and Photoreceptor Neurons in Adult Drosophila melanogaster Brains

Nervous system development involves a sequential series of events that are coordinated by several signaling pathways and regulatory networks. Many of the ...

Methods for Imaging Intracellular pH of the Follicle Stem Cell Lineage in Live Drosophila Ovarian Tissue

Methods for Imaging Intracellular pH of the Follicle Stem Cell Lineage in Live Drosophila Ovarian Tissue

Changes in intracellular pH (pHi) play important roles in the regulation of many cellular functions, including metabolism, proliferation, and ...

Dissection and Staining of Drosophila Pupal Ovaries

Dissection and Staining of Drosophila Pupal Ovaries

Unlike adult Drosophila ovaries, pupal ovaries are relatively difficult to access and examine due to their small size, translucence, and encasing within a ...

Whole Mount Immunofluorescence and Follicle Quantification of Cultured Mouse Ovaries

Research in the field of mammalian reproductive biology often involves evaluating the overall health of ovaries and testes. Specifically, in females, ...

Visualizing the Node and Notochordal Plate In Gastrulating Mouse Embryos Using Scanning Electron Microscopy and Whole Mount Immunofluorescence

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is ...

Direct Lineage Reprogramming of Adult Mouse Fibroblast to Erythroid Progenitors

Erythroid cell commitment and differentiation proceed through activation of a lineage-restricted transcriptional network orchestrated by a group of cell ...

Determining Bile Duct Density in the Mouse Liver

Mouse is broadly used as a model organism to study biliary diseases. To evaluate the development and function of the biliary system, various techniques ...