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Updated: Aug 17, 2026
Transgenic Rodent Assay for Quantifying Male Germ Cell Mutant Frequency
Published on: August 6, 2014
Protein expression analysis of rat testes induced testicular toxicity with several reproductive toxicants
Toshinori Yamamoto1, Tamio Fukushima, Rie Kikkawa
1Worldwide Safety Sciences, Pfizer Global Research & Development, Nagoya Laboratories, Pfizer Inc., Taketoyo, Aichi, Japan.
Abstract:
The utilization of safety biomarkers to predict the possibility of compound-related toxicity provides several advantages for drug discovery and development, especially at an early stage. The objectives of this study were to investigate the effects of male reproductive toxicants on protein expression profiles in the rat testes and to identify potential biomarker candidates. Four well-known reproductive toxicants, ethylene glycol monomethyl ether (EGME), cyclophosphamide (CP), sulfasalazine (SASP) and 2,5-hexanedione (2,5-HD), were administered to male rats in a single dose, and protein expression profiles were investigated after 24 hr by two-dimensional gel electrophoresis (2DE). Histopathological examination of the testes and serum concentration analysis were also performed. From the results of the comparison of 2D-gels among different doses of a compound and among compounds, 52, 20, 24 and 111 spots were nominated as differentially expressed spots with EGME, CP, SASP and 2,5-HD treatments, respectively. Several spermatogenesis-involved proteins were identified, including glutathione S-transferase (GST), testis-specific heat shock protein 70-2 (HSP70-2), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and phosphatidylethanolamine-binding protein (PEBP). Some of them were altered by more than one compound. In summary, remarkable histopathological findings were observed only in the EGME high-dose group, and most of the protein changes were detected before histopathological changes occurred. Therefore, the proteins identified in this study could potentially serve as biomarkers to evaluate male reproductive toxicity at an early stage of drug discovery and development.
Insights
This study identified potential protein biomarkers in rat testes for early detection of male reproductive toxicity. These biomarkers show changes before visible histopathological damage, aiding drug discovery.
Area of Science:
- Toxicology
- Proteomics
- Drug Discovery
Background:
- Safety biomarkers are crucial for predicting compound-related toxicity in early drug development.
- Identifying early indicators of male reproductive toxicity is essential for safer drug discovery.
Purpose of the Study:
- To investigate the impact of known male reproductive toxicants on protein expression in rat testes.
- To identify potential protein biomarker candidates for early detection of reproductive toxicity.
Main Methods:
- Four toxicants (EGME, CP, SASP, 2,5-HD) were administered to male rats.
- Protein expression profiles were analyzed using two-dimensional gel electrophoresis (2DE) after 24 hours.
- Histopathological examination and serum concentration analysis were also conducted.
Main Results:
- Differential protein expression was observed across all toxicant treatments, with 52 (EGME), 20 (CP), 24 (SASP), and 111 (2,5-HD) spots identified.
- Key proteins involved in spermatogenesis, such as GST, HSP70-2, GAPDH, and PEBP, were identified.
- Protein expression changes occurred before significant histopathological alterations, except in the high-dose EGME group.
Conclusions:
- Proteins identified in this study show promise as early biomarkers for male reproductive toxicity.
- These biomarkers can aid in the early stages of drug discovery and development by detecting toxicity before irreversible damage occurs.
