Concentration of granulocyte elastase in seminal plasma is not associated with sperm motility

Although elastase could affect sperm motility in vitro, secretory leukocyte s protease inhibitor (SLPI) prevents sperm from being attacked by elastase. The authors investigated the correlations of elastase level with sperm mot ility and SLPI level in vivo. Semen samples (n = 116) were collected and ce ntrifuged after semen analysis. Elastase and SLPI levels were determined by an enzyme immunosorbent assay. Samples were classified by elastase levels into low (<250 ng/mL), moderate (250-1,000 ng/mL), and high elastase groups (<greater than or equal to>1,000 ng/mL). Elastase levels (range, 2.8-23,97 4.4 ng/mL) were not associated with sperm motility. The median SLPI level i n the high elastase group was 15,900 ng/mL (range, 2,860-46,900 ng/mL). How ever, there was no significant correlation between elastase and SLPI levels in seminal plasma. Since SLPI forms a 1:1 complex with elastase, these res ults suggest that seminal plasma has a sufficient amount of SLPI to protect spermatozoa from elastase.