_1776567767 20260419030247000 Rovedar Daryoushbabazadeh@gmail.com Rovedar Journal of Lab Animal Research J Lab Anim. Res 2980-9703 02 11 2026 5 1 Maria Alfonsina Lizárraga https://orcid.org/0000-0001-8890-0406 Guillermo Giovambattista https://orcid.org/0000-0001-8365-3303 Rocío Mola https://orcid.org/0009-0006-6395-7098 Fabricio Maschi https://orcid.org/0000-0001-5842-5026 Martin Rumbo https://orcid.org/0000-0001-9041-6808 Introduction: Embryo transfer in murine models is a fundamental technique in biomedical studies, particularly in reproductive biology, genetic modification, and transgenic animal production. Successful implementation of this method requires appropriate laboratory infrastructure, technical expertise, and careful standardization of procedures. The present study aimed to report the first pilot embryo transfer in mice at the National University of La Plata, Argentina, and to evaluate the technique's initial feasibility and efficiency. Materials and methods: Embryos were generated by ovarian superovulation in an 8-week-old female C57BL/6J donor mouse using a single intraperitoneal injection of 10 IU of equine chorionic gonadotropin (eCG), followed 48 hours later by 10 IU of human chorionic gonadotropin (hCG). The donor female mouse was subsequently mated with a fertile C57BL/6J male mouse. The following day, the mucus plug in the donor female was examined and then euthanized by cervical dislocation. Single-cell embryos (zygotes) were obtained. Thirteen fresh embryos were surgically transferred into a 12-week-old pseudopregnant Swiss recipient female mouse using the conventional oviductal transfer technique.Results: A pregnancy rate of 61.5% was achieved following embryo transfer. The transferred embryos were one-cell zygotes collected at 0.5 days post-coitum. Eight live pups were delivered at 19.5 days post-coitum and exhibited normal postnatal development. The pups were weaned at 21 days of age. The litter consisted of five males and three females. The administration of preoperative analgesia and the use of a standardized anesthesia protocol contributed to a favorable postoperative recovery in the recipient female mouse.Conclusion: This successful pilot study can help establish local murine strain banks in Argentina, where such infrastructure is currently lacking, and highlights the potential to fully implement and benefit from cryopreservation technologies. 02 28 2026 15 20 https://creativecommons.org/licenses/by/4.0 10.58803/jlar.v5i1.97 https://jlar.rovedar.com/index.php/JLAR/article/view/97 https://jlar.rovedar.com/index.php/JLAR/article/download/97/129 https://jlar.rovedar.com/index.php/JLAR/article/download/97/129 Lizarraga MA, Posik DM, Giovambattista G. Genetic contamination in a BALB/cJ colony and the refreshing of the colony as a critical point. J Span Soc Lab Anim Sci. 2023; 99: 37-42. Available at: https://secal.es/ Diaz SL. Analisis de la situacion de la ciencia y la tecnologia de animales de laboratorio en Argentina: Elementos estrategicos para delinear una politica en el area [Analysis of the situation of science and technology laboratory animals in Argentina: Strategic elements to outline a policy in the area]. Mater thesis, Buenos Aires University, Buenos Aires. 2018. Available at: http://bibliotecadigital.econ.uba.ar/econ/collection/tpos/document/1502-1243_DiazSL 10.1177/026119299502300306 Benavides F, and Guenet JL. Murine models for human diseases. Medicina (B Aires). 2001; 61(2): 215-231. Available at: https://pubmed.ncbi.nlm.nih.gov/11374148/ 10.17226/12910 10.1590/1984-3143-ar2020-0524 Lizarraga MA, Mola R, Lombardo E, Maschi F, Ayala M, Rumbo M, et al. The effect of sunflower seed in the diet of embryos obtained by superovulation in BJ6. Nat Council Sci Tech Res. Argentina. 2024; p. 33-38. Available at: https://bicyt.conicet.gov.ar/fichas/produccion/12502500 Nagy A, Gertsenstein M, Vintersten K, Behringer R. Recovery and in vitro culture of preimplantation stage embryos. Manipulating the mouse embryo: A laboratory manual. 4th ed. Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 2014. p. 194-196. 10.19052/mv.2344 10.17843/rpmesp.2016.332.2169 10.1177/0023677219832922 10.1530/RAF-21-0087 10.1007/978-1-4939-9837-1_16 10.1186/s42826-020-00066-w