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In This Article

  • Summary
  • Abstract
  • Introduction
  • Protocol
  • Representative Results
  • Discussion
  • Acknowledgements
  • Materials
  • References
  • Reprints and Permissions

Summary

This study details the crucial factors to consider in experimental designs involving female rats. In a larger sense, these data serve to decrease stigma and assist in the development of more inclusive diagnostic and intervention tools.

Abstract

The current methodology establishes a reproducible, standardized, and cost-effective approach to monitoring the estrous cycle of female Sprague Dawley (SD) adolescent rats. This study demonstrates the complexity of hormonal cycles and the broad spectrum of understanding required to construct a reliable and valid monitoring technique. Through an in-depth examination of principal experimental design and procedural elements, this description of the cycle and its fundamental principles provides a framework for further understanding and deconstructs misconceptions for future replication.

Along with an outline of the sample collection process employing vaginal lavage, the procedure describes the mechanism of data categorization into the four-stage model of proestrus, estrus, metestrus, and diestrus. These stages are characterized by a new proposed approach, utilizing the 4 categorizing determinants of vaginal fluid condition, cell type(s) present, cell arrangement, and cell quantity at the time of collection. Variations of each stage, favorable and unfavorable samples, the distinction between cyclicity and acyclicity, and graphic depictions of the collected categorizing components are presented alongside effective interpretive and organizational practices of the data. Overall, these tools allow for the publication of quantifiable data ranges for the first time, leading to the standardization of categorization factors upon replication.

Introduction

Novel contributions
The rodent estrous cycle has been identified as an essential indicator of wellness. However, unconscious biases of investigators and inaccurate interpretations regarding the female body hinder the scientific community. The very etymology of the word "estrous" implies a sense of inferiority and negativity. Euripides used the term to describe a "frenzy" or madness, Homer to describe panic, and Plato to describe an irrational drive. This study highlights how these primeval perspectives influence the current scientific community and addresses these concerns through a novel mosaic paradigm—an update....

Protocol

All handling and procedure methods outlined in this protocol align with National Institutes of Health (NIH) animal care and use guidelines and have been approved by the Institutional Animal Care and Use Committee (IACUC) of Pepperdine University and The UCLA Chancellor's Animal Research Committee (ARC).

1. Animal care and use

  1. Acquire female rats, in numbers according to power analysis, and male rats to promote the Whitten effect or more consistent cycling46

Representative Results

The current data reflect that of female adolescent SD International Genetic Standardization Program (IGS) in the presence of male SD rats. These animals were located at both Pepperdine University and UCLA laboratories as part of a collaborative study. Figure 5 presents multiple variations of the 4 cycle stages. Figure 5A1 was identified as a diestrus sample with several cell types present. This example demonstrates that samples with a larger num.......

Discussion

Key steps and important considerations
Certain critical steps in the provided protocol require emphasis, especially within the collection of vaginal cells. During the vaginal fluid extraction, ensuring the proper angle and depth of syringe insertion is key to producing satisfactory results and ultimately preventing irritation, injury, or cervical stimulation to the animal. The stimulation of the cervix can be one source of pseudopregnancy induction, indicated by 12-14 days of a leukocyte-only vagin.......

Acknowledgements

This study was conducted through an NIH-funded collaboration between the University of California Los Angeles Brain Injury Research Center (BIRC).

....

Materials

NameCompanyCatalog NumberComments
AmScope 40X-1000X LED Student Microscope + 5MP USB CameraAmScopePart Number: M150C-E5 EAN: 0608729747796 Model Number: M150C-E5https://www.amazon.com/AmScope-40X-1000X-Student-Microscope-Camera/dp/B00O9GNOTA/ref=sr_1_15?crid=2W9CHTG8YSOTV&
keywords=usb+camera+for+microscope&
qid=1572477663&s=industrial
&sprefix=USB+camera+for+micr%2Cindustrial%2C177&sr=1-15
BD PrecisionGlide Needle Pack, 20G x 1, Short BevelFischer Scientific14-815-526https://www.fishersci.com/shop/products/bd-precisionglide-single-use-needles-short-bevel-regular-wall-4/14815526#?keyword=BD%20PrecisionGlide%20Needle%20Pack,%2020G%20x%201
Bed O Cob 1/8NEWCO93009https://andersonslabbedding.com/cob-products/bed-ocobs-8b/
Corningâ„¢ Plain Microscope Slides Plain water-white glassFischer Scientific12-553-7Ahttps://www.fishersci.com/shop/products/corning-plain-microscope-slides-microscope-slides-75-x-25mm/125537a
Corningâ„¢ Rectangular Cover GlassesFischer Scientific12-553-464https://www.fishersci.com/shop/products/corning-square-rectangular-cover-glasses-rectangle-no-1-thickness-0-13-0-17mm-size-24-x-50mm/12553464#?keyword=true
Kimberly-Clark Professionalâ„¢ Kimtech Scienceâ„¢ Kimwipesâ„¢ Delicate Task Wipers, 1-PlyFischer Scientific06-666https://www.fishersci.com/shop/products/kimberly-clark-kimtech-science-kimwipes-delicate-task-wipers-7/p-211240?crossRef=kimwipes
Labdiet Rodent Lab Chow 50lb, 15001 NEWCO Specialty and LabDiet5012https://www.labdiet.com/products/standarddiets/rodents/index.html
Linear LED Bulb, UL Type A, T8, Medium Bi-Pin (G13), 4,000 K Color Temperature, Lumens 2550 lmGrainger36UX10https://www.grainger.com/product/36UX10?gclid=CjwKCAjw_
LL2BRAkEiwAv2Y3SW1WdNdkf7
zdIxoT9R6n2DGnrToJHjv-pwCTca4ahQyExrrtWvbgwRoCi4
cQAvD_BwE&s_kwcid=AL!2966!3!335676016696
!p!!g!!led18et8%2F4%2F840&ef_id=
CjwKCAjw_LL2BRAkEiwAv2Y3SW
1WdNdkf7zdIxoT9R6n2DGnrToJ
Hjv-pwCTca4ahQyExrrtWvbgwRo
Ci4cQAvD_BwE:G:s&s_kwcid=AL!2966!3!335676016696!p!!g!!led18et8%2F4%2F840&cm_mmc=
PPC:+Google+PPC
Sodium Chloride Injection Bags, 0.9%Live Action SafetyABB079830939https://www.liveactionsafety.com/injection-iv-solution-9-sodium-chloride-1000ml-bags/
Syringe Sterile 1ml  with Luer Slip Tip - 100 Syringes by BH SuppliesBH SuppliesASIN: B07BQDRDC2 UPC: 638632928821https://www.amazon.com/1ml-Syringe-Sterile-Luer-Slip/dp/B07BQDRDC2/ref=sr_1_1_sspa?crid=13S8EGEUK90G7&
keywords=1ml+sterile+syringe&qid=
1572478649&s=industrial
&sprefix=1+ml+steri%2Cindustrial%2C187&sr=1-1-spons&psc=1&spLa=
ZW5jcnlwdGVkUXVhbGlmaWVy
PUEyRlo4NFdZWkJLWkxGJm
VuY3J5cHRlZElkPUEwMDEzODQ
yMjNWNzdWM0hTNzVBRCZlbmNy
eXB0ZWRBZElkPUEwNDI3NzAzM
0E5SzVKMkxaQVc2JndpZGdldE5h
bWU9c3BfYXRmJmFjdGlvbj1jbGlja
1JlZGlyZWN0JmRvTm90TG9nQ2
xpY2s9dHJ1ZQ==
Wire lids and floors Mouse Maternity Wire Bar LidUsed with Rat Cage (10" X 19" x 8"H )Overall dimenAllentownLV40326013https://www.labx.com/item/wire-lids-and-floors-mouse-maternity-wire-bar-lidused/LV40326013#description
Ultra Lightweight Tissue and Plastic 17' x 24' Disposable UnderpadMedlineEAN: 0480196288558
 Global Trade Identification Number: 40080196288558
https://www.amazon.com/Medline-Industries-MSC281224C-Lightweight-Disposable/dp/B00A2G67YU/ref=sr_1_4?keywords=medline+industries+surgical+pads&qid=1572475853&
sr=8-4

References

  1. Schneider, M. Adolescence as a vulnerable period to alter rodent behavior. Cell and Tissue Research. 354 (1), 99-106 (2013).
  2. Camacho-Arroyo, I., Montor, J. M. Beyond reproductive effects of sex steroids. MiniReview....

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