Visco-elasticity of seminal fluid in relation to the epididymal and accessory sex gland function and its impact on sperm motility.

Seminal viscopathy was shown to be associated with male infertility. However, our knowledge about the regulatory mechanism of this process is still limited. In semen samples from 411 men attending for fertility assessment, traditional semen parameters including visco-elasticity were assessed according to the World Health Organization guidelines. Sperm motility was evaluated by use of computer aided sperm analysis (CASA). Seminal activity of neutral alpha-glucosidase (NAG) and concentrations of prostate-specific antigen (PSA), zinc, and fructose were measured. The activity of NAG, and the concentrations of PSA and zinc were significantly lower in hyper-visco-elastic semen samples (medians: 5 vs. 8 mU/mL; 741 vs. 924 mg/L; 1 vs. 2 mM/L), than in those with normal visco-elasticity (p = 0.004, 0.005 and 0.011, respectively). When comparing the total amounts, only for seminal fructose there was a difference between samples with high visco-elasticity as compared with those of normal visco-elasticity (median: 74 vs. 53 microM/ejaculate, p = 0.007) This seminal marker was the only significant independent parameter in predicting seminal visco-elasticity in a multiple logistic regression analysis (odds ratio for the highest quartile = 4.67). Hyper-visco-elasticity was associated with a lower percentage of motile spermatozoa (43 vs. 50%, p = 0.045). Similar trend was found for the CASA motility characteristics curvilinear velocity (VCL), average path length (VAP), amplitude of lateral head displacement (ALH) (p = 0.008, 0.038 and 0.020, respectively). Our study demonstrated the interplay between the regulatory effect of post-testicular organs on semen visco-elasticity. Hyper-visco-elasticity was associated with asthenozoospermia and lower levels of VCL, VAP and ALH.