Mystery of idiopathic male infertility: is oxidative stress an actual risk?

Objective: To study the role of oxidative stress in sperm dysfunction in Turkish idiopathic infertile men.

Design: Prospective study.

Setting: Medical laboratory.

Patient(s): Semen samples from 28 idiopathic infertile men and 14 fertile men.

Intervention(s): Sperm DNA fragmentation and reactive oxygen species (ROS) formation were assayed with the terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL) test and 2',7'-dichlorodihydrofluorescein, respectively. Seminal plasma protein carbonyl groups (PC), nitrotyrosine (NT), malondialdehyde (MDA), and total thiol (SH) levels and ferric reducing antioxidant power (FRAP) were determined.

Main Outcome Measure(s): Sperm DNA fragmentation in relation to ROS formation and seminal plasma oxidative parameters.

Result(s): The number of TUNEL-positive spermatozoa from idiopathic infertile men was higher than from fertile men, and ROS formation was increased as well in infertile males. A positive correlation was detected between TUNEL-positive cells and ROS content. Seminal plasma MDA, PC, and NT levels were elevated in idiopathic infertile males. No difference was observed in the total SH content and FRAP. Seminal plasma MDA levels correlated positively with both NT and PC levels. Positive correlations were detected between DNA fragmentation and MDA, NT, and PC of seminal plasma, and between sperm ROS content and MDA levels.

Conclusion(s): The results of this study support the presence of oxidative stress in sperm dysfunction in Turkish idiopathic infertile men.