Role of seminal osmolarity in the reduction of XXXX sperm motility.

@entity1 @entity972 @entity4810 @entity19474 @entity2865 @entity1372 @entity28842 @entity460
@entity1 sperm at ejaculation are suspended in the seminal plasma, a heterogeneous mixture deriving from the testicular/epididymal fluid and from secretions of seminal vesicles, prostate and bulbourethral glands. Biochemical characteristics of seminal fluid change along the male reproductive tract when considering its inorganic and organic composition and pH but it is known that in each region of the male genital tract seminal osmolarity is higher than that of serum. It has been previously demonstrated that in invertebrate and vertebrate sperm, seminal plasma osmolarity influences sperm motility and activity, and @entity1 sperm have been shown to possess osmosensitive @entity460 entry pathway that controls important functions such as acrosome reaction and oocyte penetration. In the present study, we have determined seminal plasma osmolarity in a large number of normozoospermic fertile and asthenozoospermic infertile subjects correlating it with sperm motility percentages and kinematic characteristics determined utilizing a computerized motion analysis system. Our results confirm that seminal plasma osmolarity is higher than that of serum (336.1 +/- 20.2 vs. 291.1 +/- 6.9 @entity28842 /L, respectively). Normozoospermic subjects show seminal osmolarity values that are significantly lower with respect to asthenozoospermic @entity1 (317.8 +/- 12.2 vs. 345.2 +/- 22.6 @entity28842 /L, p<0.001), irrespective of the cause of @entity19474 . Seminal plasma osmolarity negatively correlates with sperm progressive motility percentages and kinetic characteristics (curvilinear velocity, linear velocity, linear coefficient and lateral displacements of sperm head). Furthermore, when sperm from fertile subjects were suspended in medium with an osmolarity increasing from 300 to 600 @entity28842 , sperm motility percentages and kinetics characteristics were progressively reduced and nearly abolished when medium osmolarity was 600 @entity28842 . On the contrary, when sperm from asthenozoospermic subjects with high semen osmolarity were resuspended in medium with lower osmolarity, sperm motility parameters improved significantly. Sperm motility parameters did not correlate with seminal plasma concentrations of @entity1372 , @entity972 , @entity2865 with a weak correlation only with seminal @entity460 concentration. No correlations are present between seminal plasma osmolarity and ionic composition. In conclusion, the present study confirms and extends the knowledge that, in @entity1 , seminal plasma osmolarity is higher than that of serum and demonstrates that seminal osmolarity influences sperm motility characteristics and then it may contribute to the pathogenesis of some forms of @entity19474 and @entity4810 .
