Semen hyperviscosity (SHV) is one of the factors involved in deficiency in sperm function. It seems to be associated with reduced sperm motility, possibly due to a 'trapping effect', that prevents normal sperm progression through the female genital tract. Although the negative effects of hyperviscosity on sperm parameters quality, especially on motility, are well known, the mechanism in which hyperviscous semen affecting spermatozoa are poorly understood.
It appears that one of these mechanisms includes seminal antioxidants depletion and high sperm membrane lipid peroxidation, showing to have negative effects on sperm quality and function. In the present study, we hypothesized that whether the hyperviscous semen is associated with seminal plasma antioxidants depletion and sperm membrane lipid peroxidation in infertile patients.
Semen samples were collected from fertile (n= 12), infertile patients with hyperviscosity semen (n=22) and infertile patients without hyperviscosity (n=25). After collection, semen specimens were allowed to liquefy at room temperature for 30 minutes and used for parameters analysis. On microscopic examination, sperm count, percentage of motile sperm, and sperm with normal morphology were objectively evaluated. Semen consistency was estimated by introducing a glass rod into the sample and measuring the length of the thread forming on withdrawal of the rod. Ejaculates with normal consistency had a thread length <2 cm, whereas semen classified as hyperviscous showed a thread length >2 cm. Five hundred µl of semen sample were centrifuged at 1400 xg for 7 minutes at 4˚C. The supernatants were removed from pellets and diluted 10-fold with distilled water, then immediately used for total antioxidant capacity (TAC) assay. TAC was measured by ferric reducing of antioxidant power (FRAP) method described. Sperm membrane lipid peroxidation was assessed using the thiobarbituric acid reaction (TBAR) method.
Sperm count, sperm motility and sperm normal morphology in fertile group were significantly (p<0.001, p<0.001 and p<0.01, respectively) higher than those in both infertile groups. In addition, the mean values of sperm parameters, including count, motility and normal morphology, in patient with hyperviscosity were significantly lower than those values in non-hyperviscosity patients (p<0.05, p<0.01 and p<0.001, respectively). The mean value of TAC in seminal plasma of fertile men (2346±743.54 µmol/l) was considerably higher than the related values in patients with hyperviscous (1230.25±352 µmol/l) and non-hyperviscous (1710.31± 458.67 µmol/l) semen (p<0.001). Moreover the mean value of TAC level in hyperviscous group was significantly lower than the related value in non-viscous group (p<0.01). The mean value of MDA in seminal plasma of fertile men (0.62±0.18 nmol/ml) was significantly lower than the related values in patients with hyperviscous (1.01±0.41 nmol/ml) and non-hyperviscous (0.94 ± 0.28 nmol/l) se -men (p<0.001). A trend toward a higher mean of MDA value was seen for hyperviscous com -pared with non-hyperviscous; however, this difference was not significant.
A severe impairment of seminal antioxidative systems and an increased sperm membrane lipid peroxidation are considered as indications for low quality of sperm in patients with hyperviscous semen. But the mechanism in which antioxidants in the seminal plasma of patients with hyperviscous semen occurs has not been fully elucidated. It can also say that treatment with antioxidants may be useful in patients showing abnormal semen consistency to protect sperm cells by peroxidative damage and to improve their functional properties which is merited future studies.
Dr. Eisa Tahmasbpour
Chemical Injury Research Center, Baqiatallah Medical Science University, Tehran, Iran