Abstract Study question Does sperm DNA integrity evaluated by DNA fragmentation index (DFI) and big halo pattern correlate with sperm decondensation index (SDI) and semen sample parameters? Summary answer DFI correlates with SDI and semen sample parameters in a stronger way than the big halo pattern What is known already The sperm chromatin dispersion test evaluates DNA integrity by measuring the susceptibility of sperm DNA containing breaks to denature when treated by an acid solution. Spermatozoa with intact DNA produce big or medium size halos of dispersed DNA loops, whereas small halos or no halos indicate fragmented DNA. The DFI calculates the proportion of spermatozoa with fragmented DNA. Data have been published documenting the negative effect of sperm DFI on embryo viability, suggesting that its evaluation could contribute to the prediction of the male reproductive potential Study design, size, duration A prospective study between 2011 to 2019 included 300 patients attending our clinic for fertility treatment. All sperm samples were analyzed according to WHO criteria, and the results from the DNA integrity analysis were related to the semen sample indices Participants/materials, setting, methods Of the 300 males included in the study, 118 were normozoospermic, 16 were oligozoospermic (O), 63 were asthenozoospermic (A), 9 were teratozoospermic, 7 were AT, 51 were OA, 5 were OT, and 31 OAT. The DNA integrity was assessed by the Halosperm test, and DNA decondensation by the aniline blue assay. A big halo was defined as a dispersion greater or equal to the length of the minor diameter of the core Main results and the role of chance DFI showed negative correlations with progressive motility (r= –0.532, p = 2.816 E–23), total motility (r= –0.598, p = 1.688 E–30) and morphology (r= –0.338, p = 2.954 E–9). Accordingly, when compared with normozoospermic, DFI was significantly higher in A and T samples (29.5 ±12.0 and 36.5±4.8 respectively, p < 0.002) with the highest levels found in samples with combined defects (45.2±12.5 in AT, p < 0.002; 51.3±17.2 in OAT, p < 0.002). DFI also showed a negative correlation with the big halo pattern (r= –0.656, p = 2.934 E–38) and a positive correlation with the SDI (r = 0.429, p = 7.314 E–15). For the big halo, negative correlations were found with progressive motility (r = 0.429, p = 7.314 E–15) and morphology (r = 0.407, p = 4.077 E–13) resulting in a lower incidence in T samples (27.0±9.6, p < 0.002) that was especially relevant in AT (18.3±14.5, p < 0.002), OT (33.0±10.2, p < 0.02) and OAT samples (20.6±15.8, p < 0.002). SDI presented a negative correlation with total motility (r= –0.403, p = 3.849 E–13) and was fond to be increased in A samples (32.4±11.8, p < 0.002) as well as in samples with double defects (38.9±19.2 in AT samples and 38.8±15.9 in OA samples, p < 0.002) and triple defects (42.6±16.8 in OAT, p < 0.002) Limitations, reasons for caution The study did not evaluate the lifestyle and reproductive history of the patients Wider implications of the findings: Although the effects of sperm DNA damage on reproductive outcomes are still unclear, the correlation between sperm DNA fragmentation, semen parameters and reproductive potential is emerging. DFI, big halo and SDI could contribute to the diagnosis of male infertility especially in categories of patients with poor prognosis of pregnancy. Trial registration number Not applicable
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