Unraveling how in vitro capacitation alters ram sperm chromatin before and after cryopreservation

This study aimed to investigate dynamic modifications produced in the chromatin structure of ram spermatozoa duringin vitro capacitation before and after cryopreservation.Materials and methodsChromatin decondensation (AB+), DNA methylation, DNA fragmentation index (%DFI) and high DNA stainability (HDS) were evaluated in fresh and frozen ‐thawed ram spermatozoa incubated under capacitating (CAP) conditions at 1, 5, 15, 30, 60, 120, 180 and 240 min and under non‐capacitating (NC) conditions at 0, 15 and 240 min.ResultsIncubation in NC conditions did not induce significant changes in chromatin condensation (P> 0.05; AB+ and HDS). However, incubation of fresh and cryopreserved ram spermatozoa under CAP conditions significantly increased chromatin decondensation (P< 0.05), reaching the highest percentage of AB+ and HDS from 180 to 240 min in fresh samples and from 5 to 30 min in cryopreserved samples. Both variables (HDS and AB+) were positively correlated with tyrosine phosphorylation, total motility, progressive motility, curvilinear velocity, and amplitude of lateral head displacement, as well as between them under CAP conditions in fresh and cryopreserved spermatozoa. DNA methylation significantly increased in cryopreserved spermatozoa (P< 0.05), but only after extended incubation under CAP conditions (60 ‐240 min), while the %DFI, albeit higher in cryopreserved samples, remained constant under CAP and NC conditions in both types of sample (P> 0.05).Discussio...
Source: Andrology - Category: Urology & Nephrology Authors: Tags: ORIGINAL ARTICLE Source Type: research