Claudia G Petersen, Ana L Mauri, Laura D Vagnini, Adriana Renzi, Bruna Petersen, Mariana Mattila, Vanessa Comar, Juliana Ricci, Felipe Dieamant, Joao Batista A Oliveira, Ricardo L R Baruffi, José Gonçalves Franco Jr
JBRA Assist. Reprod. 2018; 22 (4):323-330
Received December 08, 2017
Accepted June 30, 2018
Abstract
Objective: This study aimed to evaluate the effects of male age on sperm DNA damage.
Methods: This cross-sectional study included semen samples collected from 2,178 men seen at an infertility clinic. For DNA integrity analysis, the proportions of spermatozoa showing DNA fragmentation (TUNEL assay), abnormal chromatin packaging/underprotamination (chromomycin A3), abnormal mitochondrial membrane potential (MMP/MitoTracker Green), and apoptosis (annexin V) were recorded. For group comparisons, enrolled subjects were divided into three groups based on their ages: ≤35 years; 36-44 years; and ≥45 years. The associations between age and sperm parameters were assessed using Spearman's rank correlation coefficient.
Results: Although aging did not affect sperm apoptosis (p>.05), sperm DNA fragmentation and MMP deteriorated significantly with age (p<.05). Chromatin packaging/protamination improved significantly with age (p<.05).
Conclusion: Sperm DNA fragmentation worsened with age and was apparently associated with mitochondrial damage. The age-related increase in sperm DNA damage suggests that delaying childbearing, not only in women but also in men, might jeopardize a couple’s reproductive capacity. The increase seen in chromatin packaging might represent a protective feature for DNA. However, additional studies must be performed to confirm the results concerning chromatin packaging/protamination.
