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Adenovirus-mediated p53 gene transfer to rat testis impairs spermatogenesis
M Fujisawa1, T Shirakawa, H Fujioka
1Department of Urology, Kobe University School of Medicine, Japan. masato@med.kobe-u.ac.jp
Abstract:
The tumor suppressor protein p53 participates in normal cell differentiation as well as induction of programmed cell death. The authors investigated the effect of p53 overexpression on spermatogenesis by transferring p53 gene into the rat testes. Replication-deficient recombinant adenovirus vectors were constructed to include cytomegalovirus (CMV) promoter driving wild-type p53 (Ad-CMV-p53) or beta-galactosidase (Ad-CMV-beta-gal). Virus was delivered to cells of the tubules by slow retrograde injection through the rete testis. At 0, 4, 7, and 14 days, testes were removed, weighed, and analyzed histopathologically, including immunohistochemistry for p53, Bcl-2, Bax, and interleukin-1beta converting enzyme (ICE). Testicular weight was decreased in Ad-CMV-p53 group at 14 days after injection, while no change occurred in phosphate-buffered saline-injected controls or Ad-CMV-beta-gal-infected testes. Beyond 4 days, cell degradation in tubules interfered with immunohistochemical observation in the Ad-CMV-p53 group. At 4 days, p53 was expressed mostly in spermatocytes. Bax showed greater expression in the p53 group than in the control or Ad-CMV-beta-gal group. ICE, expressed mostly in spermatids, was more abundant in the p53 group than in controls. Overall, p53 overexpression in the testis impaired spermatogenesis.
Insights
Overexpressing the tumor suppressor protein p53 in rat testes impaired spermatogenesis. This gene transfer led to decreased testicular weight and increased pro-apoptotic markers, indicating cell damage.
Area of Science:
- Molecular Biology
- Reproductive Biology
- Genetics
Background:
- The tumor suppressor protein p53 is crucial for cell differentiation and apoptosis.
- Understanding p53's role in spermatogenesis is vital for reproductive health research.
Purpose of the Study:
- To investigate the impact of p53 gene overexpression on spermatogenesis in rats.
- To analyze the molecular and histological changes in testes following p53 gene transfer.
Main Methods:
- Replication-deficient recombinant adenovirus vectors carrying the wild-type p53 gene (Ad-CMV-p53) were constructed.
- Virus was delivered to rat testes via retrograde injection through the rete testis.
- Testes were analyzed histopathologically and immunohistochemically for p53, Bax, and ICE at various time points.
Main Results:
- Ad-CMV-p53 injection led to a significant decrease in testicular weight by day 14.
- Increased expression of Bax (pro-apoptotic) and ICE (caspase) was observed in the p53-overexpressing group.
- Histological analysis revealed cell degradation in tubules of Ad-CMV-p53 testes, particularly after 4 days.
Conclusions:
- Overexpression of p53 in the testis negatively impacts spermatogenesis.
- The findings suggest p53-induced apoptosis contributes to the impairment of sperm production.