Rodent Estrous Cycle Monitoring Utilizing Vaginal Lavage: No Such Thing As a Normal Cycle

Podsumowanie

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.

Streszczenie

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.

Wprowadzenie

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....

Protokół

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. Determine the strain based on the objective of the study in known databases⁴⁷.
   NOTE: The current data reflect that....

Wyniki

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.......

Dyskusje

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.......

Materiały

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