The expression of secretory leukocyte protease inhibitor (SLPI) in the fallopian tube: SLPI protects the acrosome reaction of sperm from inhibitory effects of elastase.
BACKGROUND
Secretory leukocyte protease inhibitor (SLPI) is a protein found in various fluids, including parotid secretions, cervical mucus, seminal plasma and ascites, and is a potent inhibitor of human leukocyte elastase activity. The objective of the study was 2-fold, to evaluate (i) the presence of SLPI in the Fallopian tube, and (ii) the effect of SLPI on the acrosome reaction of sperm.


RESULTS
Western blot analysis revealed that SLPI protein was detected as a 12 kDa band in the isthmus, ampulla and infundibulum of the Fallopian tube. Immunohistochemistry using an anti-SLPI polyclonal antibody revealed positive staining of epithelial cells in the Fallopian tube. RT-PCR demonstrated that SLPI transcripts were expressed in the Fallopian tube. To determine the function of SLPI in the Fallopian tube, the effects of SLPI and elastase on the sperm acrosome reaction were examined. SLPI prevented the reduction of the acrosome reaction by elastase in a dose-dependent manner.


CONCLUSIONS
The present findings suggest that SLPI in the Fallopian tube contributes to sperm-oocyte interaction.
D020101:Acrosome Reaction / Q000187:drug effects*; D000328:Adult; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000737:chemistry; D005187:Fallopian Tubes / Q000737:chemistry*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D010196:Pancreatic Elastase / Q000494:pharmacology*; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins / Q000032:analysis / Q000235:genetics* / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053481:Secretory Leukocyte Peptidase Inhibitor; D013084:Sperm-Ovum Interactions; D014018:Tissue Distribution
D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; D012333:RNA, Messenger; C506814:SLPI protein, human; D053481:Secretory Leukocyte Peptidase Inhibitor; D010196:Pancreatic Elastase