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[Chromosomal aberrations induced in human spermatozoa by mitomycin C]
Abstract:
Human spermatozoa were exposed to Mitomycin C (MM() at the concentrations of 7.5, 15, 3O micrograms/ml for 1 hour respectively before interspecific in vitro fertilization with zona-free hamster ova. The first cleavage metaphases was analyzed to investigate MMC-induced effects on human spermatozoa. The results showed a distinct dose-response relationship in the induction of chromosomal aberrations. The chromatid aberrations were the predominant types in MMC-induced changes. Some chromosome-type aberrations were also observed. This suggested that the induced effects of MMC on human spermatozoa were some different from that of ultraviolet light-like clastogens on somatic cells. 36.89% of MMC-induced aberrations were rejoining-type. This indicated that the DNA repair systems present in golden hamster oocytes were effective in repairing MMC-induced DNA lesions in human spermatozoa.
Insights
Mitomycin C (MMC) exposure caused dose-dependent chromosomal aberrations in human sperm. Hamster oocytes effectively repaired these MMC-induced DNA lesions, indicating functional DNA repair mechanisms.
Area of Science:
- Reproductive Biology
- Genetics
- Toxicology
Context:
- Investigating the genotoxic effects of chemical agents on human spermatozoa is crucial for understanding male reproductive health.
- Interspecific in vitro fertilization provides a model to assess sperm DNA integrity and repair capacity.
Purpose:
- To evaluate the clastogenic effects of Mitomycin C (MMC) on human spermatozoa.
- To analyze the types of chromosomal aberrations induced by MMC.
- To determine the efficacy of hamster oocyte DNA repair systems on MMC-induced sperm DNA damage.
Summary:
- Human spermatozoa were treated with varying concentrations of Mitomycin C (MMC) (7.5, 15, 30 µg/ml) and used for in vitro fertilization with zona-free hamster oocytes.
- Analysis of first cleavage metaphases revealed a dose-response relationship for MMC-induced chromosomal aberrations, predominantly chromatid-type, with some chromosome-type aberrations also observed.
- A significant portion (36.89%) of MMC-induced aberrations were rejoining-type, suggesting that the golden hamster oocytes possess effective DNA repair systems capable of repairing MMC-induced DNA lesions in human spermatozoa.
Impact:
- This study highlights the differential genotoxic effects of MMC on human sperm compared to known clastogens like UV light on somatic cells.
- Demonstrates the potential of the hamster oocyte as a model system to assess the repair of chemical-induced DNA damage in human sperm.
- Provides insights into the DNA repair capacity of oocytes, relevant for assisted reproductive technologies and understanding male infertility factors.