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Doxorubicin induces male germ cell apoptosis in rats
K Shinoda1, K Mitsumori, K Yasuhara
1Pathology Unit, Hita Research Laboratories, Chemicals Inspection and Testing Institute, Hita-shi, Oita, Japan. shinodak@hita.citi.or.jp
Abstract:
To clarify whether apoptosis is involved in doxorubicin (DXR)-induced testicular toxicity and to identify the target germ cell type, adult Sprague-Dawley rats were treated with a single intravenous dose of DXR (8 or 12 mg/kg) and euthanized at 3, 6, 12, 24, and 48 h subsequently. Histologically, germ cell degeneration was first found 6 h after dosing in meiotically dividing spermatocytes and early round spermatids of seminiferous tubules at stage 1, and subsequently observed in spermatogonia at stages I-VI showing ultrastructural characteristics of apoptosis. Coincident with the appearance of morphological changes, degenerating germ cells were shown to be undergoing apoptosis as revealed by in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The frequency of TUNEL-labeled germ cells increased in a stage- and cell type-specific manner, the peak of frequency gradually progressing from stage I of seminiferous tubules to later stages with time after dosing, suggesting that the damaged germ cells, especially spermatogonia, gradually underwent the processes leading to apoptosis. DNA laddering on gel electrophoresis was apparent 24 and 48 h after dosing. The results demonstrate that apoptosis plays an important role in the induction of testicular toxicity caused by DXR with meiotically dividing spermatocytes and type A and intermediate spermatogonia as highly vulnerable target cells.
Insights
Doxorubicin causes testicular toxicity through apoptosis, primarily affecting spermatocytes and spermatogonia. This study identifies key vulnerable germ cell types in rats exposed to doxorubicin.
Area of Science:
- Reproductive Toxicology
- Cell Biology
- Oncology Drug Toxicity
Background:
- Doxorubicin (DXR) is a widely used chemotherapy agent.
- Potential testicular toxicity is a significant concern with DXR treatment.
Purpose of the Study:
- To investigate the role of apoptosis in doxorubicin-induced testicular toxicity.
- To identify specific germ cell populations targeted by doxorubicin.
Main Methods:
- Adult Sprague-Dawley rats were administered single intravenous doses of doxorubicin (8 or 12 mg/kg).
- Animals were euthanized at various time points (3, 6, 12, 24, 48 hours) for histological and molecular analysis.
- In situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was used to detect apoptosis.
- DNA laddering was assessed by gel electrophoresis.
Main Results:
- Germ cell degeneration, characterized by apoptotic ultrastructure, was observed as early as 6 hours post-dosing.
- TUNEL-positive cells, indicating apoptosis, increased in a stage- and cell type-specific manner.
- Meiotically dividing spermatocytes and spermatogonia (Type A and intermediate) were identified as highly vulnerable target cells.
- DNA laddering, a marker of apoptosis, was evident 24 and 48 hours after doxorubicin administration.
Conclusions:
- Apoptosis is a critical mechanism underlying doxorubicin-induced testicular damage.
- Specific germ cell types, including spermatocytes and spermatogonia, are particularly susceptible to doxorubicin's apoptotic effects.
- These findings are crucial for understanding and potentially mitigating the reproductive side effects of doxorubicin chemotherapy.