Impact of metabolic syndrome on testicular redox status: role of an antioxidant

Abstract

Metabolic syndrome (MS) has a harmful effect on the male reproductive system. This work was aimed to elucidate the mechanisms by which MS is affecting tissues of the male reproductive system and the possible role of quercetin (QT) to revert these alterations.

Male Wistar rats were divided into: 1) controls; 2) MS (treated with 10% fructose in the drinking water for 60 days); 3) MS+ QT (50 mg/kg b.w. during last 15 days of fructose treatment); 4) control+ QT (50 mg/kg b.w. during last 15 days).  Waist circumference and body weight were measured in control and treated rats. Glucose, triglycerides, cholesterol, HDLc and testosterone were determined in blood samples. Sperm concentration, motility and acrosomal reaction were evaluated from the epididymis. Spermatogenesis and morphology were assessed in testicular sections stained with hematoxylin-PAS. Glutathione (GSH) content and superoxide dismutase (SOD) activity were determined in testis homogenates. Results were evaluated by one-way analysis of variance (ANOVA) and Tukey’s test as a post hoc.

Waist circumference, body weight, and serum triglycerides were increased and HDLc was decreased in MS rats compared to control values. All animals showed complete spermatogenesis. In MS rats, testosterone level (C:4.72±0.60; MS:2.43±0.31*; MS+QT:4.39±0.52 ng/dL; *p<0.05 vs C and MS+QT) and the motile spermatozoa percentage (C:61.7±2.33; MS:47.3±2.01*; MS+QT:74.6±2.12 %, *p<0.05 vs C and MS+QT) were lower than controls whereas QT restored those parameters. The seminiferous tubules area from MS rats was smaller than Control group. The MS rats presented lower GSH content (C:54.27±3.16; MS:39.22±1.90*; MS+QT:58.30±2.64 nmol/mg prot., *p<0.05 vs C and MS+QT) and higher SOD activity (C:9.24±0.69; MS:15.60±1.50*; MS+QT:10.95±1.92 UI/mg prot, *p<0.05 vs C and MS+QT) compared to those from the control rats. QT administration prevented those alterations and additionally, decreased spontaneous acrosomal reaction.

The results suggest that MS induced by fructose intake could decrease the testosterone synthesis and the sperm motility as a consequence of oxidative stress. QT treatment could improve the testis oxidative state and the general conditions of MS.