Evaluation of DNA integrity and chromatin condensation in cat sperm collected by urethral catheterization and epididymis slicing

Abstract

Chromatin damage is an inclusive term that accounts for any defects in DNA structure, such as DNA single or double-strand breaks, base deletion or modification, DNA inter-strand or intra-strand cross-linkage and protamine deficiency and/or mispackage (Esteves et al., 2020). It may occur during spermatogenesis, spermiogenesis, epididymal transit or post-ejaculation (Esteves et al., 2020).However, assessment of DNA structure is not usually included in routine semen analysis despite DNA status is associated with embryo development and pregnancy rates, being a better marker of fertility than conventional semen parameters (Evenson, 2016;Vernocchi et al., 2014).Techniques to evaluate chromatin damage can be divided into two main groups: (1) Sperm DNA fragmentation tests such as TUNEL (terminal dUTP nick-end labelling), ISNT (in situ nick translation assay), SCSA (sperm chromatin structure assay), SCD (sperm chromatin dispersion assay) and Comet assay; and (2) Sperm chromatin