Stain-free interferometric phase microscopy correlation with DNA fragmentation stain in human spermatozoa

Area of Science:

• Reproductive Biology
• Optical Imaging
• Sperm Analysis

Background:

• Acridine orange (AO) staining is a standard method for assessing sperm DNA fragmentation.
• This staining method can be time-consuming and may introduce artifacts.
• There is a need for non-invasive, quantitative methods for sperm evaluation.

Purpose of the Study:

• To evaluate the potential of stain-free Interferometric Phase Microscopy (IPM) for assessing sperm DNA fragmentation.
• To correlate IPM-derived parameters with traditional embryologist assessments and AO staining results.
• To determine if IPM can aid in selecting sperm with intact DNA for assisted reproductive technologies.

Main Methods:

• Sperm cells were imaged using stain-free Interferometric Phase Microscopy (IPM) to obtain morphological and refractive index data.
• IPM parameters (acrosome dry mass, size) were measured.
• The same sperm cells were subsequently stained with Acridine Orange (AO) and analyzed for DNA fragmentation levels.
• IPM parameters were correlated with embryologist (WHO-2010) and AO-based DNA fragmentation classifications.

Main Results:

• Significant differences in IPM-based parameters were observed between sperm groups with varying DNA fragmentation levels.
• IPM-derived measurements showed a correlation with both embryologist assessments and AO staining results.
• Stain-free IPM effectively distinguished between sperm cells with intact and fragmented DNA.

Conclusions:

• Stain-free Interferometric Phase Microscopy (IPM) is a viable method for assessing sperm DNA fragmentation without the need for staining.
• Digital analysis of IPM images can assist in selecting sperm with intact DNA for intracytoplasmic sperm injection (ICSI).
• This approach may enhance the efficiency of ICSI and improve pregnancy rates.