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Published on: July 8, 2020
Cysteine Supplementation During In Vitro Maturation Enhances Bovine Oocyte Developmental Competence Through Improved
Xingyu Zhang1,2,3, Xin Chen1,2,3, Ruizhen Jian1,2,3,4
1College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010011, China.
Biology
|June 25, 2026
Summary
Supplementing bovine oocyte in vitro maturation (IVM) with 75 μM cysteine enhances antioxidant capacity and mitochondrial function. This improves oocyte quality and early embryo development, crucial for efficient bovine embryo production.
Area of Science:
- Reproductive Biology
- Developmental Biology
- Cellular Physiology
Background:
- In vitro maturation (IVM) is vital for bovine embryo production but susceptible to oxidative stress, compromising oocyte quality.
- Oxidative stress negatively impacts oocyte maturation and subsequent embryonic development, necessitating strategies to improve IVM efficiency.
Purpose of the Study:
- To investigate the effects of cysteine supplementation on bovine oocyte IVM, focusing on redox homeostasis, mitochondrial status, and gene expression.
- To determine the optimal cysteine concentration for improving bovine oocyte quality during in vitro maturation.
Main Methods:
- Bovine cumulus-oocyte complexes were cultured in IVM medium with varying cysteine concentrations (0-125 μM).
- Evaluated oocyte maturation rates, fertilization, cleavage, and early embryonic development.
- Assessed cellular parameters including reactive oxygen species (ROS), glutathione (GSH), mitochondrial membrane potential, and lipid droplets.
- Conducted transcriptomic analysis (Smart-seq2) and qRT-PCR to identify differentially expressed genes.
Main Results:
- 75 μM cysteine was optimal, increasing first polar body extrusion and fertilization/cleavage rates.
- Significantly enhanced early embryonic development (2-cell to 8-cell stages) and improved redox balance (reduced ROS, increased GSH).
- Improved mitochondrial membrane potential, increased lipid droplet accumulation, and altered gene expression related to metabolism and translation.
Conclusions:
- Cysteine supplementation, particularly at 75 μM, significantly enhances bovine oocyte IVM quality and developmental potential.
- Improved outcomes are attributed to enhanced antioxidant capacity, better mitochondrial function, and optimized energy metabolism pathways.
- This finding offers a strategy to improve the efficiency of bovine in vitro embryo production.
