3-Methyl-4-nitrophenol Exposure Deteriorates Oocyte Maturation by Inducing Spindle Instability and Mitochondrial...

Area of Science:

• Reproductive toxicology
• Environmental health
• Cell biology

Background:

• 3-methyl-4-nitrophenol (PNMC) is a widespread environmental contaminant found in diesel exhaust and insecticide degradation.
• PNMC is known to be toxic to the female reproductive system.
• The specific effects of PNMC on oocyte meiosis progression remain largely unknown.

Purpose of the Study:

• To investigate the deleterious effects of PNMC on mouse oocyte maturation in vitro.
• To elucidate the mechanisms underlying PNMC-induced oocyte dysfunction, focusing on spindle stability and mitochondrial function.

Main Methods:

• In vitro maturation of mouse oocytes.
• Assessment of spindle morphology and stability.
• Analysis of mitochondrial distribution, membrane potential, ATP production, and reactive oxygen species (ROS) levels.
• Measurement of mRNA levels for mitochondria-related genes.
• Evaluation of early apoptosis markers.

Main Results:

• PNMC exposure significantly compromised oocyte maturation.
• PNMC disturbed spindle stability, decreasing density and increasing length, potentially involving the Fignl1 enzyme.
• Significant mitochondrial dysfunction was observed, including altered distribution, reduced ATP production, decreased membrane potential, and increased ROS.
• Impaired mRNA levels of mitochondria-related genes were noted.
• PNMC-induced alterations triggered early apoptosis in oocytes.

Conclusions:

• PNMC exposure negatively impacts oocyte maturation and quality.
• PNMC disrupts oocyte quality by affecting spindle stability and mitochondrial function.
• These cellular dysfunctions ultimately lead to oocyte apoptosis.