title: Nuclear degraded sperm subpopulation is affected by poor chromatin compaction and nuclease activity.
abstract: There is an interest in the nuclear degraded sperm subpopulation because, although it is present in a low percentage in all semen samples, patient groups such as varicocele and rearranged genome carriers show high levels of these degraded spermatozoa. This study is designed with two objectives in mind: first, incubations of H2 O2 and nuclease on DTT-treated and untreated samples to show the aetiology of this subpopulation and second, assessment of the correlation between the protamine ratio and nuclear degraded spermatozoa. A very high increase in the nuclear degraded subpopulation has been found with nuclease incubation, and it is even higher when it has been merged with nuclear decompaction using DTT. Alternatively, incubation with H2 O2 with and without DTT did not show such a significant increase in nuclear degraded spermatozoa. The protamine ratio correlated with this subpopulation, showing, in patients, that poor nuclear compaction would turn the sperm susceptible to degradation. Then, the assessment of nuclear degraded spermatozoa might not be only a measure of DNA degradation but also an indicator of chromatin compaction in the spermatozoa. Different patient groups would fit this model for sperm nuclear degradation, such as varicocele patients, who show a high percentage of immature spermatozoa and nuclear degraded spermatozoa, and reorganised genome carriers, where reorganisation might also cause poor chromatin compaction on the sperm nucleus.
authors.affiliation: Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Ribas-Maynou
authors.forename: A
authors.initials: A
authors.lastname: García-Peiró
authors.forename: J
authors.initials: J
authors.lastname: Martínez-Heredia
authors.forename: A
authors.initials: A
authors.lastname: Fernández-Encinas
authors.forename: C
authors.initials: C
authors.lastname: Abad
authors.forename: M J
authors.initials: MJ
authors.lastname: Amengual
authors.forename: J
authors.initials: J
authors.lastname: Navarro
authors.forename: J
authors.initials: J
authors.lastname: Benet
mesh_terms: D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D053938:DNA Fragmentation; D003851:Deoxyribonucleases / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007248:Infertility, Male / Q000235:genetics / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002843:Chromatin; D006861:Hydrogen Peroxide; D003851:Deoxyribonucleases
keywords: Nuclear degraded spermatozoa; nuclease activity; oxidative stress; sperm DNA fragmentation; varicocele