Octocrylene exposure impairs mouse oocyte quality by inducing spindle defects and mitochondria dysfunction.

Area of Science:

• Environmental Science
• Toxicology
• Reproductive Biology

Background:

• Octocrylene (OCL) is a widely used organic UV filter found in cosmetics.
• OCL environmental contamination is increasing, with detected presence in soil, sediment, aquatic systems, and food chains.
• Previous studies indicate OCL's reproductive toxicity in aquatic organisms, but its effects on oocyte quality remain under-investigated.

Purpose of the Study:

• To investigate the impact of Octocrylene (OCL) exposure on mouse oocyte maturation and quality.
• To assess OCL's effects on in vitro oocyte maturation, including germinal vesicle breakdown (GVBD) and polar body extrusion (PBE).
• To evaluate OCL's influence on oocyte cellular functions, such as spindle assembly, chromosome alignment, mitochondrial function, and apoptosis.

Main Methods:

• Mouse oocytes were exposed in vitro to varying concentrations of Octocrylene (OCL) (8, 22, 30, 40, and 50 nM).
• Assessed key meiotic maturation events: germinal vesicle breakdown (GVBD) and polar body extrusion (PBE).
• Analyzed spindle and chromosome status, mitochondrial function (ROS production), apoptosis, cortical granule distribution, and sperm binding ability.

Main Results:

• OCL significantly reduced GVBD rates at 50 nM and PBE rates at 40 and 50 nM.
• OCL exposure disrupted spindle assembly and chromosome alignment, leading to aneuploidy.
• Mitochondrial dysfunction, increased reactive oxygen species (ROS) production, and apoptosis were observed in OCL-exposed oocytes.
• Impaired cortical granule distribution and reduced sperm binding ability were also noted.

Conclusions:

• Octocrylene (OCL) exposure negatively impacts mouse oocyte meiotic maturation.
• OCL disrupts critical cellular processes within oocytes, compromising their overall quality.
• These findings highlight potential risks associated with OCL exposure to female reproductive health.