Background: Previous studies have demonstrated an association between obesity and the decreased male fertility.
Objective: to observe the mechanisms by which obesity affects semen quality.
Materials and methods: A prospective study was performed including 47 male volunteers, of which 27 were obese group (body mass index >30 kg/m2 ) and 20 were eutrophic (body mass index between 18.5 and 25 kg/m2 ) controls. Sperm functional analysis was performed. The remaining seminal plasma was pooled-four pools per group- and submitted to proteomic analysis by liquid chromatography coupled to tandem mass spectrometry. Groups were compared by an unpaired Student's t-test. Differentially expressed proteins were submitted to functional enrichment analysis using the online platform PantherDB.
Results: Obese men presented decreased non-progressive motility, morphology, acrosome integrity, mitochondrial activity, and increased sperm DNA fragmentation. In proteomics analysis, 69 proteins were differentially expressed between the two groups. Among them, one protein was absent, 19 were down-regulated, 49 were up-regulated, and one was exclusive in the study group. The main functions enriched were as follows: negative regulation of the intrinsic pathway of apoptosis, activation of immune and inflammatory, antioxidant activity, among others.
Conclusion: molecular pathways suggest there is a causative link, and that the effector mechanisms alter sperm metabolic status and defective testicular selection 5 mechanisms.
Keywords: DNA fragmentation; obesity; proteomics; seminal plasma; spermatozoa.
© 2019 American Society of Andrology and European Academy of Andrology.