Delayed and Progressive Post Exposure Testicular Injury in Rats Due to Fine Particulate Matter (PM2.5)

Area of Science:

• Environmental Toxicology
• Reproductive Biology
• Male Reproductive Health

Background:

• Fine particulate matter (PM2.5) is linked to male reproductive issues.
• Existing research primarily focuses on acute effects, leaving long-term, progressive testicular damage poorly understood.

Purpose of the Study:

• To investigate the persistent and progressive nature of testicular damage following PM2.5 exposure.
• To assess recovery and long-term consequences of PM2.5 exposure on male reproductive health in a rat model.

Main Methods:

• A time-resolved rat model exposed intranasally to PM2.5 for 7 days.
• Evaluation of sperm quality, reproductive organ indices, testicular histology, and ultrastructure.
• Measurement of serum reproductive hormones and inflammatory cytokines, assessment of germ cell apoptosis, and analysis of junctional and stress-related proteins.

Main Results:

• Sustained declines in sperm concentration and motility, increased malformations, and testicular/epididymal atrophy were observed post-exposure.
• Progressive thinning of seminiferous epithelium, ultrastructural degeneration, and persistent endocrine disruption (reduced testosterone, altered gonadotropins).
• Elevated inflammatory cytokines (IL-1β, IL-6), increased germ cell apoptosis, downregulated junctional proteins (Connexin-43, Occludin), and JNK pathway activation.

Conclusions:

• PM2.5 exposure induces delayed and progressive testicular toxicity that does not recover after exposure cessation.
• Maintaining junctional integrity and targeting the JNK pathway may be potential strategies to mitigate long-term reproductive harm from PM2.5.