Related Experiment Video
Updated: May 17, 2026
Whole Ovary Immunofluorescence, Clearing, and Multiphoton Microscopy for Quantitative 3D Analysis of the Developing Ovarian Reserve in Mouse
Published on: September 3, 2021
Factors related to unstained areas in whole ewe ovaries perfused with a metabolic marker
A Torre1, F Ben Brahim, T Popowski
1INSERM U846, Stem-cell and Brain Research Institute, 18 Avenue Doyen Lepine, Bron 69500, France. antoinetorre@voila.fr
Study Question:
What factors are associated with the presence of areas unexposed to the perfusate after whole ovary perfusion?
Summary Answer:
Over half the ovaries perfused with the metabolic marker methylthiazolyl blue tetrazolium (MTT) were incompletely stained. Incomplete staining was statistically significantly associated with a small ovarian slice surface area, inexperience of the experimenter, and the presence of a corpus luteum.
What Is Known Already:
Whole ovary cryopreservation followed by vascular auto-transplantation has provided poor outcomes as an alternative way to safeguard fertility. Perfusion, commonly used to expose the ovaries to cryoprotectants, may miss areas excluded from the vascular network, explaining subsequent poor ovarian functionality.
Study Design, Size, Duration:
An observational study of 360 ewe ovaries stained by in vitro perfusion with MTT as a qualitative marker of tissue blood supply was performed. A logistic regression model was built to identify factors associated with incomplete ovary staining.
Materials, Setting, Methods:
Whole ewe ovaries with their vascular pedicles were perfused at 0.35 ml/min with 1 g/l MTT for 2 h at 39°C under 19 experimental conditions. The pedicles were removed and the ovaries cut in half sagittally and photographed. The unstained area of the slice surface was measured. Times from ovary collection to ovary rinsing and to MTT perfusion initiation, ovary weight and slice surface area, presence of a corpus luteum and operator experience (number of ovaries previously perfused) were recorded. Pedicle MTT staining was quantified at 564 nm after solubilization in alcohol.
Main Results And The Role Of Chance:
Unstained areas were observed in 64.4% of the ovaries. Multivariate analysis found that incomplete ovary staining was independently associated with lower experimenter experience (P < 0.02), smaller ovary slice surface area (P < 0.0001) and presence of a corpus luteum (P < 0.01). The presence of unstained areas was independent from experimental conditions. The rate of incomplete ovary staining decreased from 83 to 60% beyond the 80th perfused ovary (P < 0.0001).
Limitations, Reasons For Caution:
Descriptive study.
Wider Implications Of The Findings:
Blood-supply impairments that result in incomplete perfusion might adversely affect outcomes after whole ovary cryopreservation. Improved perfusion techniques should enhance success.
Insights
Whole ovary perfusion is often incomplete, with over half of ovaries showing unstained areas. Factors like smaller ovarian size, less experimenter experience, and the presence of a corpus luteum are linked to poor perfusion.
Area of Science:
- Reproductive biology
- Cryopreservation techniques
- Vascular perfusion studies
Background:
- Whole ovary cryopreservation for fertility preservation has yielded poor outcomes.
- Vascular perfusion is crucial for cryoprotectant delivery but may miss tissue areas.
- This can lead to reduced ovarian functionality post-transplantation.
Purpose of the Study:
- To identify factors associated with incomplete perfusate distribution in whole ovaries.
- To understand the causes of perfusion-related issues in ovarian cryopreservation.
Main Methods:
- An observational study involving 360 ewe ovaries.
- In vitro perfusion with methylthiazolyl blue tetrazolium (MTT) as a blood supply marker.
- Logistic regression analysis to determine factors linked to incomplete staining.
Main Results:
- 64.4% of ovaries exhibited unstained areas, indicating incomplete perfusion.
- Smaller ovarian slice surface area, less operator experience, and the presence of a corpus luteum were significant factors.
- Perfusion success improved with operator experience, with rates decreasing beyond the 80th perfused ovary.
Conclusions:
- Incomplete ovarian perfusion is common and linked to specific anatomical and procedural factors.
- Impaired blood supply due to poor perfusion may negatively impact whole ovary cryopreservation outcomes.
- Improving perfusion techniques is essential for enhancing the success of fertility preservation strategies.
