Swollen Ampulla as an Indicator of Successful Pregnancy in B6C3F1 Recipient Mice used for Assisted Reproduction

Journal of the American Association for Laboratory Animal Science, vol. 63, pp. 89–98

Abstract

In vitro fertilization (IVF), embryo cryopreservation, and embryo transfer (ET) are assisted reproductive technologies (ARTs) that are used extensively for the maintenance of mouse models in animal research. Inbred mouse strains with different genetic backgrounds vary in their reproductive performance. Cryopreservation can affect embryo quality and viability, and the genetic background of ET recipients can influence the ET result. In this retrospective study, we analyzed the out- comes of ETs performed in our facility during the last 6 y. We found that B6C3F1 mice with swollen ampullae show almost 3-fold higher pregnancy rates than mice with nonswollen ampullae when either freshly isolated or frozen-thawed embryos are implanted. Implantation of freshly collected embryos in recipients with swollen ampullae led to significantly higher pregnancy rates in comparison to implantation of frozen-thawed embryos, regardless of whether the latter were fertilized in vivo or in vitro. Moreover, we found a significant effect of genetic background on the birth rate; C57BL/6J mice and mice with a mixed genetic background had 34% higher birth rates than did C57BL/6N mice. Within the C57BL/6J group, the birth rates were significantly higher when using fresh in vivo-fertilized embryos, and cryopreservation negatively affected both in vivo- and in vitro-fertilized embryos. The success rate of obtaining one living pup was not significantly different between frozen-thawed and fresh embryos. Overall, a swollen ampulla is a strong indicator for a successful pregnancy, together with the embryo manipulation and genetic background. A better understanding of the factors that affect the reproductive outcome might lead to optimization of the ART protocols and contribute to a reduction in the number of mice used for these procedures.

Authors 7

1. Christina Gougoula

   Heinrich Heine University Düsseldorf

   Affiliation as printed

   Central Unit for Animal Research and Animal Welfare Affairs (ZETT) of the Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany;

2. W. Peter M. Benten

   Heinrich Heine University Düsseldorf

   Affiliation as printed

   Central Unit for Animal Research and Animal Welfare Affairs (ZETT) of the Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany;

3. Ani Kaplanian

   Academy of Athens · Biomedical Research Foundation of the Academy of Athens

   Affiliation as printed

   Center for Basic Research, Biomedical Research Foundation Academy of Athens (BRFAA), Athens, Greece; and

4. Laurentiu Benga

   Heinrich Heine University Düsseldorf

   Affiliation as printed

   Central Unit for Animal Research and Animal Welfare Affairs (ZETT) of the Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany;

5. Ivonne Jeanette Knorr Aachen Faculty of Medicine Institute for Laboratory Animal Science and Experimental Surgery

   RWTH Aachen University · Heinrich Heine University Düsseldorf

   Affiliation as printed

   Central Unit for Animal Research and Animal Welfare Affairs (ZETT) of the Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany;

   Institute for Laboratory Animal Science and Experimental Surgery, Rheinische-Westfälische Technische Hochschule Aachen University, Faculty of Medicine, Aachen, Germany

6. Eva Engelhardt

   Heinrich Heine University Düsseldorf

   Affiliation as printed

   Central Unit for Animal Research and Animal Welfare Affairs (ZETT) of the Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany;

7. Martin Sager

   Heinrich Heine University Düsseldorf

   Affiliation as printed

   Central Unit for Animal Research and Animal Welfare Affairs (ZETT) of the Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany;