This work was supported in part by a DoD Breakthrough Award to AMW (BCRP W81XWH-14-1-0425). KCR was partially supported by intramural fellowships: the Pease Cancer Pre-Doctoral Fellowship and the Mary Galvin Burden Pre-Doctoral Fellowship in Biomedical Sciences and University of California, Riverside, intramural awards: the Graduate Council Fellowship Committee Dissertation Research Grant and the Graduate Division Dissertation Year Program Award. The authors thank Gillian M. Wright and Alyssa M. Kumari for assistance in early troubleshooting of this method.

All animal handling and procedures were approved by the University of California, Riverside institutional animal care and use committee and were in accordance with guidelines from the American Association for Laboratory Animal Care, the United States Department of Agriculture, and the National Institutes of Health. The described method utilized C57BL/6 adult, female mice. All animals were euthanized by decapitation prior to tissue harvesting.
NOTE: An overview of the protocol, which uses a blu...

<ol>
	<li>Stewart, C. A., et al., Kubiak, J. Z., 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> Mouse oviduct developmemt in Mouse Development: From Oocyte to Stem Cells. , 247-262 (2012).</li><li>Ford, M. J., 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=Oviduct+epithelial+cells+constitute+two+developmentally+distinct+lineages+that+are+spatially+separated+along+the+distal-proximal+axis.">Oviduct epithelial cells constitute two developmentally distinct lineages that are spatially separated along the distal-proximal axis.</a> Cell Reports. 36 (10), 109677 (2021).</li><li>Harwalkar, 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=Anatomical+and+cellular+heterogeneity+in+the+mouse+oviduct-its+potential+roles+in+reproduction+and+preimplantation+development.">Anatomical and cellular heterogeneity in the mouse oviduct-its potential roles in reproduction and preimplantation development.</a> Biology of Reproduction. 104 (6), 1249-1261 (2021).</li><li>Agduhr, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+on+the+structure+and+development+of+the+bursa+ovarica+and+the+tuba+uterina+in+the+mouse.">Studies on the structure and development of the bursa ovarica and the tuba uterina in the mouse.</a> Acta Zoologica. 8 (1), 1 (1927).</li><li>Pulkkinen, M. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oviductal+function+is+critical+for+very+early+human+life.">Oviductal function is critical for very early human life.</a> Annals of Medicine. 27 (3), 307-310 (1995).</li><li>Kindelberger, D. W., 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=Intraepithelial+carcinoma+of+the+fimbria+and+pelvic+serous+carcinoma:+Evidence+for+a+causal+relationship.">Intraepithelial carcinoma of the fimbria and pelvic serous carcinoma: Evidence for a causal relationship.</a> American Journal of Surgical Pathology. 31 (2), 161-169 (2007).</li><li>Ghosh, A., Syed, S. M., Tanwar, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+genetic+cell+lineage+tracing+reveals+that+oviductal+secretory+cells+self-renew+and+give+rise+to+ciliated+cells.">In vivo genetic cell lineage tracing reveals that oviductal secretory cells self-renew and give rise to ciliated cells.</a> Development. 144 (17), 3031-3041 (2017).</li><li>Lee, Y., 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+candidate+precursor+to+serous+carcinoma+that+originates+in+the+distal+fallopian+tube.">A candidate precursor to serous carcinoma that originates in the distal fallopian tube.</a> Journal of Pathology. 211 (1), 26-35 (2007).</li><li>Kim, J., 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-grade+serous+ovarian+cancer+arises+from+fallopian+tube+in+a+mouse+model.">High-grade serous ovarian cancer arises from fallopian tube in a mouse model.</a> Proceedings of the National Academy of Sciences of the United States of America. 109 (10), 3921-3926 (2012).</li><li>Perets, 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=Transformation+of+the+fallopian+tube+secretory+epithelium+leads+to+high-grade+serous+ovarian+cancer+in+Brca;Tp53;Pten+models.">Transformation of the fallopian tube secretory epithelium leads to high-grade serous ovarian cancer in Brca;Tp53;Pten models.</a> Cancer Cell. 24 (6), 751-765 (2013).</li><li>Sherman-Baust, C. 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=A+genetically+engineered+ovarian+cancer+mouse+model+based+on+fallopian+tube+transformation+mimics+human+high-grade+serous+carcinoma+development.">A genetically engineered ovarian cancer mouse model based on fallopian tube transformation mimics human high-grade serous carcinoma development.</a> Journal of Pathology. 233 (3), 228-237 (2014).</li><li>Zhai, Y. 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=High-grade+serous+carcinomas+arise+in+the+mouse+oviduct+via+defects+linked+to+the+human+disease.">High-grade serous carcinomas arise in the mouse oviduct via defects linked to the human disease.</a> Journal of Pathology. 243 (1), 16-25 (2017).</li><li>Karthikeyan, 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=Prolactin+signaling+drives+tumorigenesis+in+human+high+grade+serous+ovarian+cancer+cells+and+in+a+spontaneous+fallopian+tube+derived+model.">Prolactin signaling drives tumorigenesis in human high grade serous ovarian cancer cells and in a spontaneous fallopian tube derived model.</a> Cancer Letters. 433, 221-231 (2018).</li><li>Shao, 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=Differences+in+prolactin+receptor+(PRLR)+in+mouse+and+human+fallopian+tubes:+Evidence+for+multiple+regulatory+mechanisms+controlling+PRLR+isoform+expression+in+mice.">Differences in prolactin receptor (PRLR) in mouse and human fallopian tubes: Evidence for multiple regulatory mechanisms controlling PRLR isoform expression in mice.</a> Biology of Reproduction. 79 (4), 748-757 (2008).</li><li>Alwosaibai, 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=PAX2+maintains+the+differentiation+of+mouse+oviductal+epithelium+and+inhibits+the+transition+to+a+stem+cell-like+state.">PAX2 maintains the differentiation of mouse oviductal epithelium and inhibits the transition to a stem cell-like state.</a> Oncotarget. 8 (44), 76881-76897 (2017).</li><li>Peri, L. E., 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+novel+class+of+interstitial+cells+in+the+mouse+and+monkey+female+reproductive+tracts.">A novel class of interstitial cells in the mouse and monkey female reproductive tracts.</a> Biology of Reproduction. 92 (4), 102 (2015).</li><li>L&#245;hmussaar, 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=Assessing+the+origin+of+high-grade+serous+ovarian+cancer+using+CRISPR-modification+of+mouse+organoids.">Assessing the origin of high-grade serous ovarian cancer using CRISPR-modification of mouse organoids.</a> Nature Communications. 11 (1), 2660 (2020).</li><li>Chen, 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=An+air-liquid+interphase+approach+for+modeling+the+early+embryo-maternal+contact+zone.">An air-liquid interphase approach for modeling the early embryo-maternal contact zone.</a> Scientific Reports. 7, 42298 (2017).</li><li>Desjardins, P., Conklin, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NanoDrop+microvolume+quantitation+of+nucleic+acids.">NanoDrop microvolume quantitation of nucleic acids.</a> Journal of Visualized Experiments: JoVE. (45), e2565 (2010).</li><li>Schroeder, 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=The+RIN:+an+RNA+integrity+number+for+assigning+integrity+values+to+RNA+measurements.">The RIN: an RNA integrity number for assigning integrity values to RNA measurements.</a> BMC Molecular Biology. 7, 3 (2006).</li><li>McGlade, E. 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=Cell-type+specific+analysis+of+physiological+action+of+estrogen+in+mouse+oviducts.">Cell-type specific analysis of physiological action of estrogen in mouse oviducts.</a> The FASEB Journal. 35 (5), 21563 (2021).</li></ol>

The authors have nothing to disclose.

The three segments of the oviduct are histologically, morphologically, and functionally distinct1,2,3. The epithelium varies greatly from one end of the oviduct to the other. Ciliated cells dominate at the fimbrial/infundibular end, while secretory cells dominate in the isthmic region1. While this overall gradient has been recognized for some time, recent work has uncovered more distinctions among the ovi...

The murine oviduct is similar in function and morphology to the human fallopian tube1. Both consist of a pseudostratified ciliated epithelium, consisting of two historically described epithelial resident cells: ciliated cells and secretory cells1,2. The oviduct has three classically recognized segments: the infundibulum, the ampulla, and the isthmus. In a recent study, Harwalkar et al.3 investigated oviduct morphology and gene expression leading to the expansion of the categorization of resident epithelial cells to seven distinct populations. In addition, they established the ampullary-isthmus junction as a distinct segment of the oviduct3. The method described herein, which focuses on the infundibulum, ampulla, and isthmus, could easily be extended to include the ampullary-isthmic junction as well2,3. The infundibular region contains the ostium, or opening of the oviduct, and includes the fimbrial region as well as the proximal stalk. Moving toward the uterus, next is the ampulla, and then the isthmus. Ciliated cells are most prominent in the distal end of the region, proximal to the ovary, or infundibulum, while secretory cells are most prominent in the proximal end or isthmus segment1. Unlike the human fallopian tube, the murine oviduct is a coiled structure supported by the mesosalpinx, an extension of the broad ligament peritoneum1,4. In addition, the mouse oviduct is encased in a bursal sac that increases the likelihood of oocyte transfer into the oviduct4. The ampulla is identified as the location of fertilization, from which developing embryos pass into the isthmus before entering the uterus5. Tubal segments are 200-400 &#956;m in diameter and the longer ampullary and isthmus regions are approximately 0.5-1.0 cm in length4. The oviduct distends during the estrous cycle and the ampulla and infundibulum are more distensible than the isthmus1.
Over proliferation of cells, especially secretory cells, characterize precursor lesions to serous tumors found in the pelvic cavity6. These precursor serous intraepithelial lesions arise in the oviduct epithelium solely in the fimbrial region; it is unknown why lesion formation is restricted to this region where normally the predominant cell type is ciliated, not secretory2,7,8. The regionality in terms of normal physiological function, as well as heightened interest in the oviductal origin of ovarian cancer9,10,11,12,13, underscores the importance of separate evaluation of the oviduct segments.
The method described here details the collection of separate oviductal segments for subsequent downstream analyses of segment-specific gene expression and function of dissociated cells. Traditionally, many tissues are processed for whole RNA extraction following either the phenol: chloroform method or an on-column complete extraction method; however, we found that RNA quality was maintained while producing sufficient yield with the described combination method. Utilizing this method, very small functional segments of the oviduct can be processed for downstream analyses rather than investigating the oviduct as a whole, which can mask results representative of the different segments14.
Dissociated murine oviductal cells have rarely been investigated by flow cytometry, most likely due to the limiting cell yield from this tissue. One approach to overcome this problem has been to dissociate cells, grow them in culture, and then stimulate re-differentiation in vitro to obtain appropriate cell numbers for downstream cell analysis15,16,17,18. A limitation to this approach is the time ex vivo and altered microenvironment in culture, both of which likely change gene expression. There is also an assumption that morphological re-differentiation has the same transcriptional and proteomic signature as was present in the intact animal. The current dissociation method was designed to achieve the highest number of epithelial cells in a heterogenous oviductal cell population while maintaining single cell differentiation. Further, the mostly non-enzymatic approach likely limits the loss of cell surface proteins.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.5 mm Stainless steel bead mix</td>
			<td>Next Advance</td>
			<td>SSB05</td>
			<td>Mix 1:1 with 1.4 mm SSB14B, sterilized</td>
		</tr>
		<tr>
			<td>1.4 mm Stainless steel bead mix</td>
			<td>Next Advance</td>
			<td>SSB14B</td>
			<td>Mix 1:1 with 0.5 mm SSB05, sterilized</td>
		</tr>
		<tr>
			<td>1X Dulbecco&#39;s Phosphate Buffered Saline A, pH 7.4 (DPBS)</td>
			<td>Gibco</td>
			<td>21600-010</td>
			<td>Cold, sterile</td>
		</tr>
		<tr>
			<td>25G needle</td>
			<td>BD</td>
			<td>305122</td>
			<td></td>
		</tr>
		<tr>
			<td>60 mm sterile petri dishes</td>
			<td>Corning</td>
			<td>430166</td>
			<td></td>
		</tr>
		<tr>
			<td>70 &#956;m cell meshes</td>
			<td>Fisherbrand</td>
			<td>22-636-548</td>
			<td></td>
		</tr>
		<tr>
			<td>Agilent Eukaryote Total RNA 6000 Pico Chip kit</td>
			<td>Agilent 2100 Bioanalyzer</td>
			<td>5067-1513</td>
			<td></td>
		</tr>
		<tr>
			<td>Bead Bullet Blender Tissue Homogenizer</td>
			<td>Next Advance</td>
			<td>BBY24M</td>
			<td></td>
		</tr>
		<tr>
			<td>Bioanlyzer</td>
			<td>Agilent 2100 Bioanalyzer</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Sigma Aldrich</td>
			<td>A7906</td>
			<td></td>
		</tr>
		<tr>
			<td>Cold plate/pack/surface of choice</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Kept at -20C for dissection</td>
		</tr>
		<tr>
			<td>Dental wax</td>
			<td>Polysciences Inc.</td>
			<td>403</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s Modified Eagle&#8217;s Medium (DMEM)/ Ham&#8217;s F12</td>
			<td>Corning</td>
			<td>10-090-CV</td>
			<td>Prepare dissection medium: DMEM/ Ham&#8217;s F12, 10% FBS, 25 mM Hepes, 1% Pen-Strep</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Corning</td>
			<td>35-015CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine point forceps of choice</td>
			<td>N/A</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Sigma Aldrich</td>
			<td>G712b</td>
			<td>Immunocytochemical validation images</td>
		</tr>
		<tr>
			<td>Goat anti-mouse IgG Alexa Fluor 555</td>
			<td>Invitrogen</td>
			<td>A-21422</td>
			<td>Immunocytochemical validation images</td>
		</tr>
		<tr>
			<td>Goat anti-rabbit IgG Alexa Fluor 488</td>
			<td>Invitrogen</td>
			<td>A-11001</td>
			<td>Immunocytochemical validation images</td>
		</tr>
		<tr>
			<td>Hepes</td>
			<td>Sigma Aldrich</td>
			<td>H-3784</td>
			<td></td>
		</tr>
		<tr>
			<td>Hoescht 33342</td>
			<td>Cell Signaling Technologies</td>
			<td>4082S</td>
			<td>Immunocytochemical validation images</td>
		</tr>
		<tr>
			<td>Inverted compound microscope</td>
			<td>Keyence BZ-X700</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse anti-mouse Occludin</td>
			<td>Invitrogen</td>
			<td>33-1500</td>
			<td>Immunocytochemical validation images</td>
		</tr>
		<tr>
			<td>Non-enzymatic dissociation buffer</td>
			<td>N/A</td>
			<td></td>
			<td>5 mM EDTA, 1 g/L glucose, 0.4% BSA, 1X DPBS</td>
		</tr>
		<tr>
			<td>Nylon macro-mesh 1 mm x 1 mm</td>
			<td>Thomas Scientific</td>
			<td>1210U04</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma Aldrich</td>
			<td>P-6148</td>
			<td>Immunocytochemical validation images</td>
		</tr>
		<tr>
			<td>Pen-Strep</td>
			<td>MP Biomedicals</td>
			<td>10220-718</td>
			<td></td>
		</tr>
		<tr>
			<td>Prolong Gold Antifade Reagent</td>
			<td>Cell Signaling Technologies</td>
			<td>9071S</td>
			<td>Immunocytochemical validation images: antifade mounting medium</td>
		</tr>
		<tr>
			<td>Pronase</td>
			<td>Sigma Aldrich</td>
			<td>10165921001</td>
			<td>Prepare pronase digestion medium: 0.15% Pronase in DMEM/Ham&#39;s F12, sterile</td>
		</tr>
		<tr>
			<td>Propidium Iodide</td>
			<td>Roche</td>
			<td>11 348 639 001</td>
			<td>Viability validation images</td>
		</tr>
		<tr>
			<td>Rabbit anti-mouse Acetylated-Tubulin</td>
			<td>Abcam</td>
			<td>ab179484</td>
			<td>Immunocytochemical validation images</td>
		</tr>
		<tr>
			<td>RBC lysis buffer</td>
			<td>BD Biosciences</td>
			<td>555899</td>
			<td></td>
		</tr>
		<tr>
			<td>RNeasy Mini Kit</td>
			<td>Qiagen</td>
			<td>74134</td>
			<td>Utilized for on-column purification in text.</td>
		</tr>
		<tr>
			<td>Spring form microdissection scissors</td>
			<td>Roboz Surgical</td>
			<td>RS-5610</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile 3 mL bulb pipettors</td>
			<td>Globe Scientific</td>
			<td>137135</td>
			<td></td>
		</tr>
		<tr>
			<td>Toluidine blue</td>
			<td>Alfa Aesar</td>
			<td>J66015</td>
			<td>Prepare toluidine blue solution: 1% in 1X DPBS, sterile</td>
		</tr>
		<tr>
			<td>Tris-Buffered Saline-Tween (TBST)</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Immunocytochemical validation images; 0.1 N NaCl, 10 mM Tris-Cl pH 7.5, 1% Tween 20</td>
		</tr>
		<tr>
			<td>Triton-X-100</td>
			<td>Mallinckrodt Inc.</td>
			<td>3555</td>
			<td>Immunocytochemical validation images</td>
		</tr>
		<tr>
			<td>Trizol RNA Extraction Reagent</td>
			<td>Invitrogen</td>
			<td>15596026</td>
			<td>Referred to as RNA extraction reagent. Nucelase-free water, chloroform and isoproponal are required in supplement of performing Trizol extraction per manufacturer&#39;s guidelines</td>
		</tr>
	</tbody>
</table>

microdissection and dissociation of the murine oviduct: individual segment identification and single cell isolation

Mouse model systems are unmatched for the analysis of disease processes because of their genetic manipulability and the low cost of experimental treatments. However, because of their small body size, some structures, such as the oviduct with a diameter of 200-400 &#956;m, have proven to be relatively difficult to study except by immunohistochemistry. Recently, immunohistochemical studies have uncovered more complex differences in oviduct segments than were previously recognized; thus, the oviduct is divided into four functional segments with different ratios of seven distinct epithelial cell types. The different embryological origins and ratios of the epithelial cell types likely make the four functional regions differentially susceptible to disease. For example, precursor lesions to serous intraepithelial carcinomas arise from the infundibulum in mouse models and from the corresponding fimbrial region in the human fallopian tube. The protocol described here details a method for microdissection to subdivide the oviduct in such a way to yield a sufficient amount and purity of RNA necessary for downstream analysis such as reverse transcription-quantitative PCR (RT-qPCR) and RNA sequencing (RNAseq). Also described is a mostly non-enzymatic tissue dissociation method appropriate for flow cytometry or single cell RNAseq analysis of fully differentiated oviductal cells. The methods described will facilitate further research utilizing the murine oviduct in the field of reproduction, fertility, cancer, and immunology.

The described dissociation protocol yields 100,000-120,000 cells per mouse with pooling of both oviducts. The method is gentle enough to leave multi-ciliated cell borders intact, allowing for a distinction between multi-ciliated cells and secretory cells, and verifying that the digestion method is gentle enough to prevent de-differentiation. Representative immunofluorescence images in Figure 5 show small cell clumps following step 4.2.1, fixed for 3 min in 4% paraformaldehyde (PFA)/ DPBS, wa...

Watch this Scientific Journal Video about Microdissection and Dissociation of the Murine Oviduct: Individual Segment Identification and Single Cell Isolation at JoVE.com

Microdissection and Dissociation of the Murine Oviduct: Individual Segment Identification and Single Cell Isolation

A method for microdissection of the mouse oviduct that allows collection of the individual segments while maintaining RNA integrity is presented. In addition, non-enzymatic oviductal cell dissociation procedure is described. The methods are appropriate for subsequent gene and protein analysis of the functionally different oviductal segments and dissociated oviductal cells.

Mouse model systems are unmatched for the analysis of disease processes because of their genetic manipulability and the low cost of experimental ...

Different oviduct segments have distinct physiological functions and are differentially susceptible to pathological change. Identification of the different segments in a very small mouse oviduct is challenging, as is the production of a good yield of well-differentiated cells by tissue dissociation. In this video, we will demonstrate how to uncoil the mouse oviduct, recognize the different segments so that they can be analyzed individually, and finally, how to produce a relatively high yield of differentiated dissociated cells.A better understanding of the environment specific to the ampulla may improve in vitro fertilization techniques. Also, by contrasting the infundibulum with other segments, we may better understand the infundibulum's propensity for malignant transformation. The single-cell dissociation procedure liberates stromal, as well as epithelial cells from the oviduct.Our method also provides opportunities to separately analyze immune, smooth muscle, and epithelial cell contributions to physiology and pathology of the oviduct. Working under a dissection microscope can be difficult at first. I would advise practicing with a larger tube such as the uterus to ensure that your tools are adequate for the oviduct microdissection.Begin by affixing a piece of dental wax to a Petri dish with adhesive and letting it dry. Then sanitize the dish with 70%ethanol. The surface is now ready for dissection.Immobilize the Petri dish containing the dental wax on the cold platform under a dissection microscope when ready for dissection. Disinfect the ventral surface of the animal with 70%ethanol. Then open the abdominal and pelvic cavity with sterile dissection scissors.Move the gastrointestinal tract to one side to locate the dorsal bihornal uterus. Follow each uterine horn rostrally to locate each oviduct and ovary that are enveloped in the uterine fat pad just below the kidney. Then excise both lateral oviducts with the ovaries and a portion of the distal uterine horn still attached using dissection scissors.Cut each lateral uterine horn with approximately one to two centimeters of the horn still attached to the coiled oviduct and ovary. Submerge the tissue immediately in two milliliters of cold dissection medium, then affix the uterine tissue to the dental wax with a sterile 25 gauge needle to secure tissue for dissection. Clean and dissect the ovarian fat pad and connective tissue to visualize the oviduct clearly.Use a one milliliter syringe to dispense one to two drops of sterile 1%toluidine blue dye solution and incubate for 30 seconds to one minute. Rinse with cold DPBS and then remove all the liquid. Lightly pull the ovary from the coiled oviduct.Cut at the bursal membrane in the broad ligament to remove the ovary from the oviduct without compromising the tubal tissue. Locate the distal fimbrial end of the oviduct found lateral to the uterine tubal junction. Gently pull the tube and cut away at the mesosalpinx with springform micro-scissors to uncoil the oviduct.Cut the tube to produce the infundibular region. Then excise the ampullary region by cutting between turns two and three. Finally, cut the remaining portion to the uterine tubal junction which is the isthmic region.Immediately snap freeze the dissected tissue segments in liquid nitrogen and then add 200 microliters of cold RNA extraction reagent and one-to-one homogenization bead mix to the tissue for RNA isolation. Starting at the fimbrial region, slit the tube longitudinally with springform scissors and use forceps as leverage to expose the luminal epithelium. Mince the slit open portions and the remaining oviduct into approximately one to two millimeter segments.Then add five milliliters of warm non-enzymatic dissociation buffer to the tissue and incubate at 37 degrees Celsius. Fluorescent and phase contrast images of a cell cluster positive for occludin, nuclei, and acetylated tubulin are shown here. Red denotes occludin, blue denotes nuclei, and green denotes acetylated tubulin.The ciliated apical border remains intact throughout the protocol and withstands further digestion to single cells. In these representative images, merged, red, blue, phase contrast, and green channels are shown. After a brief pronase incubation, the majority of cells are single.Propidium iodide staining shows approximately 93%viability in Brightfield, red channel PI positive, and merge. Inset on merge shows an intact ciliated border on a single dissociated cell. Such cells have actively beating cilia.Whole RNA was assessed for yield and quality by microvolume spectrophotometer and bioanalyzer. Results show that this method yields 800 to 1, 200 nanogram RNA per segment except for infundibular samples where pooling from two animals may be necessary for appropriate yield for downstream assays. The presented results for infundibulum are pooled from two animals, totaling four infundibular regions.This protocol successfully achieves pure RNA analyzed with a microvolume spectrophotometer and a bioanalyzer. Samples have a 260 by 280 nanometer absorption ratio between 1.8 and 2, typical of pure RNA nucleotide species. Bioanalyzing the samples showed high RNA integrity with assessed RNA integrity number above seven, appropriate for downstream expression and sequencing analysis.Remember to retain one to two centimeters of the uterine horn to affix the tubal system to the dissection platform. In addition, the use of the toluidine blue dye helps in the fast uncoiling of the oviduct. The faster the uncoiling, the better the preservation and the least amount of RNA degradation.This method is sufficient to obtain RNA of appropriate quality for RNA sequencing allowing individual segment sequencing. The cell dissociation is appropriate for single-cell sequencing or flow cytometry allowing a more precise segment and cell analysis. The method will help move the field beyond whole tube analysis that masks differences at the segment or single cell level.

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Research

JoVE Journal

Developmental Biology

3.4K Views.  University of California, Riverside. Different oviduct segments have distinct physiological functions and are differentially susceptible to pathological change. Identification of the different segments in a very small mouse oviduct is challenging, as is the production of a good yield of well-differentiated cells by tissue dissociation. In this video, we will demonstrate how to uncoil the mouse oviduct, recognize the different segments so that they can be analyzed individually, and finally, how to produce a relatively high yield ...