Nonylphenol exposure affects mouse oocyte quality by inducing spindle defects and mitochondria dysfunction

Area of Science:

• Reproductive Biology
• Environmental Toxicology
• Cell Biology

Background:

• Nonylphenol (NP) is an industrial chemical with known toxicity to multiple systems.
• NP's effects on mammalian oocyte quality and maturation are not well understood.
• Oocyte quality is crucial for successful fertilization and embryonic development.

Purpose of the Study:

• To investigate the impact of Nonylphenol exposure on mouse oocyte maturation and quality.
• To elucidate the cellular and molecular mechanisms underlying NP-induced oocyte damage.

Main Methods:

• Mice were exposed to NP for 4 weeks.
• Oocyte maturation, follicle counts, and developmental competence were assessed.
• Transcriptomic analysis, spindle/chromosome staining, mitochondrial membrane potential, ROS, and apoptosis assays were performed.

Main Results:

• NP exposure increased atretic follicles and reduced oocyte developmental competence.
• Over 800 genes were differentially expressed in NP-exposed oocytes, affecting multiple pathways.
• NP disrupted meiotic spindle organization, caused chromosome misalignment, and impaired mitochondrial function.
• NP exposure led to increased reactive oxygen species (ROS), oxidative stress, and early apoptosis in oocytes.

Conclusions:

• Nonylphenol exposure significantly reduces mouse oocyte quality.
• NP affects cytoskeletal dynamics and mitochondrial function, leading to oxidative stress and apoptosis.
• These findings highlight the reproductive risks associated with NP environmental exposure.