ABSTRACT
Objective To assess sperm chromatin structure assay (SCSA) and sperm chromatin dispersion test (SCD) for DNA fragmentation evaluation in human infertility, and the correlation between these two methods. Methods We used SCSA and SCD assays to detect DNA fragmentation in sperm from 134 infertile men. The correlation of SCSA and SCD assays was analyzed. The sperm DNA fragmentation index (DFI) was divided into 3 groups (≤15%DFI, >15~≤30%DFI and>30%DFI), and the difference between SCSA and SCD assays was assessed. Results The SCSA assay was strongly correlated with the SCD assay for sperm DNA fragmentation (r=0.915, P15~ ≤30%DFI and>30%DFI groups. However, SCD showed higher levels of DNA fragmentation than that measured by SCSA for≤15%DFI group (13.50 4.82 vs 9.79 2.60, P<0.001). Conclusion There is a strong positive correlation between SCSA and SCD assays in detection of DNA fragmentation. SCD assay showed higher levels of DNA fragmentation than that measured by SCSA for≤15%DFI group.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate variation of sperm DNA fragmentation index (DFI) in male partners of infertile couples.</p><p><b>METHODS</b>A total of 539 males between April 2009 and April 2012 were analyzed. At least one repeated routine semen analysis and sperm DNA fragmentation test were performed for each sample by sperm chromatin dispersion (SCD) analysis following World Health Organization guidelines. Coefficient of variation (CV) for DFI was calculated.</p><p><b>RESULTS</b>Respectively, 1, 2, 3 and 4 repeated SCD analyses were carried out on 473, 59, 6 and 1 semen samples. The median interval between the first and repeated SCD measurements was 3.0 (1.0-11.0) months. For the first tested samples, the between-sample coefficient of variation (CVB) for DFI was 71.2%. A significant difference has been found between DFI of the first measurement and DFI of repeated measurement in 0.5 to 3 months, 3 to 12 months and 12 to 34 months (P< 0.01). Compared with the first test, 26.3% of males were on both sides of the cut-off point of 18%. The median within-subject coefficient of variation (CVw) for DFI of 539 men was 26.0% (12.6%-42.8%). And the median CVw DFI was significantly lower compared with CVw of sperm count, concentration, progressive motility and normal morphology (P< 0.01). Significant correlations were found between the CVw DFI and sperm count, concentration and interval among the samples (P< 0.05).</p><p><b>CONCLUSION</b>DFI of male partners for infertile couples is a parameter with substantial variation, repeated SCD measurements are therefore recommended.</p>