Mild hypothermia as an approach to increase cryotolerance of in vitro-produced bovine embryos

• Grant number: 22/10065-1
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2023
• End date: May 31, 2025
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Agreement: CONFAP - National Council of State Research Support Foundations
• Principal Investigator: Marcos Roberto Chiaratti
• Grantee: Marcos Roberto Chiaratti
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated researchers: Rafael Vilar Sampaio ; Ricardo Perecin Nociti
• Associated scholarship(s): 24/21740-7 - Determination of chromatin and transcriptomic changes in bovine embryos exposed to cold shock and slow freezing, BP.TT; 23/02285-4 - Determination of chromatin and transcriptomic changes in bovine embryos exposed to cold shock and slow freezing, BP.TT

Abstract

Bovine in vitro embryo production (IVP) is one of the most used reproductive biotechnologies, being Brazil raked in the runner-up position among countries making use of this technology. Embryo cryopreservation is required for storing exceeding embryos and transport to other regions/countries, but the efficiency of this technology is considered low, with a range of outcomes following cryopreservation. Cryotolerance can be influenced by exposition to a mild cold stress, seeking to prime the embryo to freezing. Mammalian cells own na intracelular mechanism that protect them from cold temperature, being this orchastrated by cold shock proteins that are rapidly expressed following a decreased in temperature. Here, we aim to investigate the cellular and molecular effects of exposing IVP-derived bovine embryos to mild hypothermia (cold priming), which we expect to have a protective role during cryopreservation. According to our hypothesis, the cold priming will induce a rapid epigenetic and trasncriptional adaptative response to the cold (including expression of cold shock proteins), enhancing the cryotolerance of IVP-derived embryos. In a 1st phase (UFPA), IVP-derived bovine embryos will be produced, subjected or not to cold priming, then cryopreserved/thawed, and assessed as for expansion, hatching, number of cells, and apoptosis. In a 2nd phase (UFSCar), the experimental group that best responded to the cold priming and cryopreservation, including controls, will be assessed as for chromatin (ATAC-Seq) and transcriptome (RNA-Seq) profiles. Western blotting, fluorescence microscopy, among other approaches depending on the findings, will be used to confirm/explore the data. The present proposal é unique and we expect to contribute with a more efficient protocol for embryo cryopreservation, benefiting Pará, São Paulo, and Brazilian agrobusiness. (AU)