HIGHER FREQUENCY OF TAIL DEFECTS IN HUMAN SPERMATOZOA CORRESPOND TO HIGHER LEVELS OF DNA FRAGMENTATION
DIMITAR PARVANOV* , VILYANA GEORGIEVA, VLADIMIR STAYKOV, GUEORGUI STAMENOV,
TODOR CHAUSHEV
Nadezhda,Women’s Health Hospital, 3 “Blaga vest” Street, Sofia, Bulgaria
*Corresponding author: dimparvanov@abv.bg
Keywords: human spermatozoa, tail defects, DNA fragmentation
Abstract: Numerous studies have demonstrated the presence of increased levels of sperm DNA fragmentation in patients with poor sperm morphology. The majority of studies have shown that specific head abnormalities (long, amorphous and micro heads) are associated with the presence of spermatozoa with immature chromatin and higher DFI (DNA fragmentation index). During spermatogenesis the process of chromatin compaction is considered to be tightly linked to the head morphology. However, it could also be suggested that there is relationship between DNA integrity and other morphological defects.
A retrospective study was performed during the period 2015 - 2016. A native sperm from 98 patients undergoing ICSI procedure were used for analysis of DNA fragmentation and sperm morphology. Using the Sperm Chromatin Structure Assay (SCSA), the number of DNA fragmented sperm, expressed as DNA fragmentation index (DFI) was evaluated. Sperm morphology was assessed by Kruger strict criteria after staining procedure with Sperm Stain kit (Microptic S.L.). Spearman’s rank correlation test was performed to evaluate the correlation between the frequency of the morphological defects and levels of DNA fragmentation.
Among all types of morphological defects, tail defects showed the strongest correlation with DNA fragmentation of human spermatozoa. A significant positive correlation was observed between DFI and percentage of cumulative tail defects (r = 0.54; p < 0.001), acephalic cell (pinhead) (r = 0.46; p < 0.001), short tail (r = 0.37; p = 0.022) and coiled tail (r = 0.34; p = 0.015).
In conclusion, the analysis of our data indicates that the frequency of occurrence of tail defects should be considered as a valuable biomarker of sperm DNA fragmentation.