High-throughput sperm DNA analysis at the single-cell and population levels

Area of Science:

• Reproductive Biology
• Biomedical Engineering
• Clinical Diagnostics

Background:

• Semen quality assessment is crucial for infertility treatment and offspring health.
• Sperm DNA integrity testing offers vital prognostic information.
• Current gold-standard flow cytometry is not widely used clinically; simpler methods like the sperm chromatin dispersion (SCD) assay are low-throughput and subjective.

Purpose of the Study:

• To develop and validate an automated method for quantitative sperm DNA quality assessment.
• To enable a clinically viable, high-throughput, and objective alternative to manual SCD assays.

Main Methods:

• Development of an automated optical microscopy system for chromatin diffusion-based analysis.
• Leveraging automated analysis to measure the sperm DNA diffusion coefficient (D_DNA) and population-level sperm DNA fragmentation (% sDF).
• Comparison of automated SCD results with flow cytometry-based sperm chromatin structure assay (SCSA) metrics.

Main Results:

• The automated SCD assay assesses thousands of sperm in under 10 minutes, a significant improvement over manual methods.
• Automated D_DNA measurements strongly correlate with SCSA DNA fragmentation index (DFI) (R² = 0.96).
• Automated % sDF measurements show excellent agreement with SCSA % DFI (R² = 0.98) and eliminate inter-observer variations.

Conclusions:

• The automated SCD analysis provides a standardized, rapid, and quantitative method for assessing sperm DNA integrity.
• This technology facilitates the clinical application of sperm DNA integrity testing, improving infertility diagnosis and treatment.
• The developed method addresses the limitations of traditional SCD assays, offering objective and efficient sperm quality assessment.