ObjectiveTo investigate the correlation of the levels of reproductive hormones and oxidative stress in the seminal plasma with semen parameters in obese males.

METHODSBased on the body mass index (BMI), we divided 138 infertile men into three groups: normal (BMI <24 kg/m2, n = 48), overweight (24 kg/m2≤BMI<28 kg/m2, n = 47), and obesity (BMI ≥28 kg/m2, n = 43). We determined the concentrations of follicle-stimulating hormone (FSH), luteotropic hormone (LH), prolactin (PRL), testosterone (T) and estradiol (E2) in the serum by electrochemiluminescence and measured the levels of superoxide dismutase (SOD), glutathione-S-transferases (GSTs), reactive oxygen species (ROS) and malondialdehyde (MDA) in the seminal plasma by ELISA, compared the above indexes among the three groups, and analyzed their correlation with the semen volume, sperm concentration, total sperm count, and percentage of progressively motile sperm (PMS).

RESULTSThe semen volume was significantly lower in the obesity than in the normal group (［2.63 ± 0.74］ vs ［3.37 ± 1.00］ ml, P < 0.05), and so was the percentage of PMS in the overweight and even lower in the obesity than in the normal group (［47.91 ± 12.89］ and ［41.27 ± 15.77］ vs ［54.04 ± 13.29］%, P < 0.05). Compared with the normal group, both the overweight and obesity groups showed markedly decreased levels of serum T (［4.83 ± 1.42］ vs ［3.71 ± 1.22］ and ［3.49 ± 1.12］ ng/ml, P<0.05), T/LH ratio (1.53 ± 0.57 vs 1.19 ± 0.54 and 0.97 ± 0.51, P<0.05), SOD (［112.05 ± 10.54］ vs ［105.85 ± 6.93］ and ［99.33 ± 8.39］ U/ml, P<0.05), and GSTs (［31.75±6.03］ vs ［29.54±5.78］ and ［29.02±4.52］ U/L, P<0.05), but remarkably increased seminal plasma ROS (［549.93±82.41］ vs ［620.61±96.13］ and ［701.47±110.60］ IU/ml, P<0.05) and MDA (［7.46 ± 2.13］ vs ［8.72 ± 1.89］ and ［10.47 ± 2.10］ nmol/L, P<0.05). BMI was correlated positively with ROS and MDA, but negatively with the semen volume, PMS, T, T/LH, SOD and GSTs (P<0.05); LH negatively with sperm concentration, total sperm count and GSTs (P<0.05); PRL negatively GSTs (P<0.05); E2 positively with SOD (P<0.05); T positively with SOD (P<0.05) but negatively with MDA (P<0.05); T/LH positively with PMS and SOD (P<0.05) but negatively with ROS and MDA (P<0.05); SOD positively with semen volume, PMS and GSTs (P<0.05) but negatively with ROS and MDA (P<0.05); GSTs negatively with sperm concentration; total sperm count and MDA (P<0.05); ROS positively with MDA (P<0.01) but negatively with PMS (P<0.05); and MDA negatively with semen volume (P<0.05). Multivariate logistic regression analysis showed that the independent factors influencing the semen volume were BMI and GSTs, those influencing the total sperm count were BMI and T, and those influencing PMS were BMI and MDA.

CONCLUSIONSIncreased BMI induces changes in the levels of male reproductive hormones and seminal plasma oxidative stress and affects semen quality, which may be associated with male infertility.