Study of the Metabolomics of Equine Preovulatory Follicular Fluid: A Way to Improve Current In Vitro Maturation Media

Abstract

Production of equine embryos in vitro is currently a commercial technique and a reliable way of obtaining offspring. In order to produce those embryos, immature oocytes are retrieved from postmortem ovaries or live mares by ovum pick-up (OPU), matured in vitro (IVM), fertilized by intracytoplasmic sperm injection (ICSI), and cultured until day 8–10 of development. However, at best, roughly 10% of the oocytes matured in vitro and followed by ICSI end up in successful pregnancy and foaling, and this could be due to suboptimal IVM conditions. Hence, in the present work, we aimed to elucidate the major metabolites present in equine preovulatory follicular fluid (FF) obtained from postmortem mares using proton nuclear magnetic resonance spectroscopy (1H-NMR). The results were contrasted against the composition of the most commonly used media for equine oocyte IVM: tissue culture medium 199 (TCM-199) and Dulbecco’s modified eagle medium/nutrient mixture F-12 Ham (DMEM/F-12). Twenty-two metabolites were identified in equine FF; among these, nine of them are not included in the composition of DMEM/F-12 or TCM-199 media, including (mean ± SEM): acetylcarnitine (0.37 ± 0.2 mM), carnitine (0.09 ± 0.01 mM), citrate (0.4 ± 0.04 mM), creatine (0.36 ± 0.14 mM), creatine phosphate (0.36 ± 0.05 mM), fumarate (0.05 ± 0.007 mM), glucose-1-phosphate (6.9 ± 0.4 mM), histamine (0.25 ± 0.01 mM), or lactate (27.3 ± 2.2 mM). Besides, the mean concentration of core metabolites such as glucose varied (4.3 mM in FF vs. 5.55 mM in TCM-199 vs. 17.5 mM in DMEM/F-12). Hence, our data suggest that the currently used media for equine oocyte IVM can be further improved.

Oocyte metabolic function, lipid composition, and developmental potential are altered by diet in older mares

“…Omega-3 PUFA supplementation has been associated with systemic hypolipidemic effects ( Madsen et al 1999 ), but it did not affect fatty acid concentrations in the serum of pregnant and lactating mares ( Hodge et al 2017 ). The concentrations of l -carnitine in the present study were consistent with previous reports in equine follicular fluid and plasma ( Foster et al 1988 , Zeyner & Harmeyer 1999 , Fernández-Hernández et al 2020 ). A short-term increase in systemic l -carnitine occurs after oral ingestion in horses; however, plasma concentrations are only increased for a few hours after ingestion ( Zeyner & Harmeyer 1999 ).…”

A drastic shift in the energetic landscape of toothed whale sperm cells

“…Data analysis was done using the TopSpin 3.5 software (Bruker Biospin GmbH). 69 Free induction decays were multiplied by an exponential function equivalent to 0.3 Hz line-broadening before applying Fourier transform. All transformed spectra were corrected for phase and baseline distortions and referenced to the DSS singlet at 0 ppm.…”

Human Adipose-Derived Stem Cells’ Paracrine Factors in Conditioned Medium Can Enhance Porcine Oocyte Maturation and Subsequent Embryo Development

“…An essential requirement for the success of IVM of the mammalian oocyte is to provide a rich microenvironment for oocyte culture, mimicking the in vivo reproductive tract [ 4 , 5 ]. Despite great efforts to the establishment of optimal culture medium conditions [ 6 , 7 ], numerous studies still have been performed to seek new additives [ 8 , 9 , 10 ] or somatic cell-based coculture systems [ 4 , 11 ] to obtain a better quality of oocytes. The somatic cell coculture system removes reactive oxygen species (ROS) and provides paracrine factors, which gives beneficial effects on oocyte development [ 12 ].…”