# Effect of Alpha-Lipoic Acid on the Development, Oxidative Stress, and Cryotolerance of Bovine Embryos Produced In Vitro

## TL;DR

This study explores how alpha-lipoic acid affects oxidative stress, development, and freezing tolerance in lab-grown bovine embryos.

## Contribution

The study reveals that alpha-lipoic acid reduces oxidative stress and improves hatching rates in bovine embryos after thawing.

## Key findings

- Alpha-lipoic acid reduced reactive oxygen species levels in grade II embryos.
- Hatching rates increased in grade I and II embryos after warming when alpha-lipoic acid was used.
- Embryo development and quality were not affected by alpha-lipoic acid inclusion.

## Abstract

Antioxidants are used to control reactive oxygen species for optimizing in vitro embryo development. We evaluated the effects of including alpha-lipoic acid (ALA) in in vitro production media on the alleviation of oxidative stress, development, and cryotolerance of bovine embryos. Embryos were produced in vitro using conventional protocols, with the inclusion of ALA in production media at different stages. Embryo development and hatching kinetics were not affected when different ALA concentrations were included only in the maturation or culture medium or in both. However, ALA inclusion in both the media reduced reactive oxygen species levels in grade II embryos and increased hatching after 12 h on day 7 in grade I embryos and on day 8 in grade II embryos after warming. These findings prompt questions regarding the potential of ALA in improving embryonic metabolism.

Oxidative stress (OS) induced by an imbalance in reactive oxygen species (ROS) levels in vitro impairs embryonic development. Here, we assessed the effects of alpha-lipoic acid (ALA) in in vitro production media on OS reduction, embryonic development, and cryotolerance of bovine embryos. We evaluated the effects of adding different concentrations of ALA (2.5, 5, 10, and 25 μM) to in vitro maturation (IVM) or in vitro culture (IVC) medium on embryonic development. We also determined the effects of adding ALA (25 μM) to the IVM and IVC medium in the same routine on the development and quality of embryos, ROS levels, and cryotolerance. Embryos were produced in vitro using conventional protocols for each treatment. The inclusion of ALA in the IVM and IVC media did not affect the development or quality of embryos; however, it reduced ROS levels in grade II embryos and increased hatching after 12 h on day 7 in grade I embryos and on day 8 in grade II embryos after warming. These findings prompt questions regarding the potential of ALA in improving embryo metabolism, considering the initial embryo recovery in the first few hours of embryo warming.