The effects of temperature variation treatments on embryonic development: a mouse study

Dóris Ferreira Moriyama,Mary-Naya Maalouf,Petra Adamova,Irineu Francisco Delfino Silva Massaia,Marcela De Oliveira Pinheiro,Gabrielle Ferrante Alves De Moraes,Dimitra Makri,Walid E Maalouf,Danilo Lessa Bernardineli,Edson Guimarães Lo Turco

doi:10.1038/s41598-022-06158-y

Abstract

Since the development of ART, embryos have been cultured at 37 °C in an attempt to mimic the in vivo conditions and the average body temperature of an adult. However, a gradient of temperatures within the reproductive tract has been demonstrated in humans and several other mammalian species. Therefore, the aim of this study was to evaluate the effects of temperature variation treatments on mouse embryo quality through morphokinetic events, blastocyst morphology, the relative gene expression of Igf2, Bax, Bcl2 and Apaf1 and the metabolomics of individual culture media. Study groups consisted of 2 circadian treatments, T1 with embryos being cultured at 37 °C during the day and 35.5 °C during the night, T2 with 38.5 °C during the day and 37 °C during the night and a control group with constant 37 °C. Our main findings are that the lower-temperature group (T1) showed a consistent negative effect on mouse embryo development with “slow” cleaving embryos, poor-quality blastocysts, a higher expression of the apoptotic gene Apaf1, and a significantly different set of amino acids representing a more stressed metabolism. On the other hand, our higher-temperature group (T2) showed similar results to the control group, with no adverse effects on blastocyst viability.

Highlights

Since the development of ART, embryos have been cultured at 37 °C in an attempt to mimic the in vivo conditions and the average body temperature of an adult
Data from 161 blastocysts were analysed to examine the effects of temperature variation treatments on morphokinetic events of embryo development before implantation
The Treatment 1 (T1) group showed a higher mean of relative timings, which indicates a slower development of the embryos cultured at 37/35.5 °C when compared to Treatment 2 (T2) (38.5/37 °C) and C (37 °C)

Summary

Introduction

Since the development of ART, embryos have been cultured at 37 °C in an attempt to mimic the in vivo conditions and the average body temperature of an adult. The aim of this study was to evaluate the effects of temperature variation treatments on mouse embryo quality through morphokinetic events, blastocyst morphology, the relative gene expression of Igf[2], Bax, Bcl[2] and Apaf[1] and the metabolomics of individual culture media. This study aimed to investigate the effects of temperature variation treatments on mouse embryo quality through morphokinetic events and blastocyst morphology. Blastocyst quality was evaluated individually at the molecular level through the relative gene expression of the following stress and apoptotic genes: Igf[2], Bax, Bcl[2] and Apaf[1] and through the targeted metabolomics of culture media, focusing on the main amino acids involved in preimplantation embryonic development. Based on the existing knowledge, the hypothesis of the present study is whether temperature variation treatments impair the developmental competence and quality of mouse embryos

Objectives

Methods

Results

Discussion

Conclusion