X-ray induced DNA double-strand breaks in human sperm

Area of Science:

• Reproductive biology
• Molecular toxicology
• Genetics

Background:

• DNA double-strand breaks (DSBs) are critical lesions impacting male fertility.
• Quantifying DSBs in human sperm is essential for assessing reproductive risks.
• Existing methods may lack sensitivity or require extensive sample preparation.

Purpose of the Study:

• To establish and validate a novel methodology for quantifying DNA double-strand breaks in human sperm.
• To assess the dose-dependent effects of X-ray irradiation on sperm DNA integrity.
• To investigate the potential for early repair of X-ray-induced DSBs in human sperm.

Main Methods:

• Human sperm samples from healthy donors were exposed to varying doses of X-rays (12.5-100 cGy).
• Neutral electrophoresis was employed to quantify DNA migration, indicative of DSBs.
• Sperm chromatin decondensation was achieved using extended RNase and proteinase K treatments.

Main Results:

• A linear dose-response relationship was observed between X-ray dose and DNA migration.
• Significant DNA migration, indicating DSBs, was detected at doses as low as 12.5 cGy.
• All samples irradiated at 25 cGy and above showed clear evidence of DNA damage.
• No significant repair of X-ray-induced DSBs was detected within a 2-hour post-irradiation period.

Conclusions:

• The described methodology effectively quantifies X-ray-induced DNA double-strand breaks in human sperm.
• Human sperm DNA is sensitive to low doses of ionizing radiation, with rapid induction of DSBs.
• Short-term repair mechanisms for these DSBs appear limited in human sperm.