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Testicular abnormalities in male rats after lactational exposure to nonylphenols
P C Lee1, P Arndt, K C Nickels
1Department of Pediatrics, Medical College of Wisconsin, Milwaukee, USA. pclee@mcw.edu
Abstract:
Lactational exposure of male rat pups to nonylphenols (NPs) decreased the size of their testes and male accessory glands. At 31 d of age, NP-treatment of male rats resulted in less cellular differentiation of the seminiferous tubules (STs) and increased intertubular space compared to controls. At maturity, NP-treated males showed varying degrees of abnormalities in the affected testes. In the moderately affected ones, about 20-30% of their STs had poorly differentiated germinal elements. Cell lineage was less organized. In extreme cases, all STs of the affected testis failed to differentiate into germinal elements. These abnormalities in germinal element differentiation might be the primary cause for a number of the NP-treated males having a lower epididymal sperm count and a lower percentage of motile sperm compared to age-matched control males. Zymogram analysis of testis homogenates by sodium dodecyl sulfate gelatin gels revealed two major forms (64-66 kDa and 50-52 kDa) of gelatinases. Only the 50-52-kDa form was greatly reduced or absent in the affected testis. Lactational exposure of male pups to NPs thus leads to various testicular abnormalities including lack of differentiation of STs, lowering of sperm count, and reduction in the percentage of motile sperm and modulation of a specific form of testicular proteinases.
Insights
Lactational exposure to nonylphenols (NPs) harms male rat pup reproductive development, causing testicular abnormalities and reduced sperm quality. These findings highlight the impact of environmental endocrine disruptors on male reproductive health.
Area of Science:
- Reproductive Toxicology
- Endocrinology
- Environmental Health
Background:
- Nonylphenols (NPs) are environmental contaminants with endocrine-disrupting potential.
- Prenatal and lactational exposures are critical windows for reproductive system development.
Purpose of the Study:
- To investigate the effects of lactational nonylphenol exposure on male rat pup reproductive development.
- To assess testicular morphology, sperm parameters, and specific proteinase activity.
Main Methods:
- Male rat pups were exposed to nonylphenols during lactation.
- Testicular size, seminiferous tubule differentiation, and intertubular space were evaluated.
- Epididymal sperm count and motility were assessed.
- Zymogram analysis identified gelatinase forms in testis homogenates.
Main Results:
- Nonylphenol exposure led to decreased testes and accessory gland size.
- Reduced seminiferous tubule cellular differentiation and increased intertubular space were observed.
- NP-treated males exhibited lower sperm counts and motility, with reduced 50-52 kDa gelatinase activity.
Conclusions:
- Lactational nonylphenol exposure causes significant testicular abnormalities in male rats.
- Impaired germinal element differentiation and altered proteinase activity contribute to reduced sperm quality.
- These findings underscore the reproductive risks associated with nonylphenol exposure during development.
