Redox regulation of sperm surface thiols modulates adhesion to the fallopian tube epithelium.
Sperm that adhere to the fallopian tube epithelium are of superior quality and adhesion extends their fertile life. It has been postulated that periovulatory signals, as yet undefined, promote sperm release. In the in vitro studies described here, we examined the effects of several antioxidants, reportedly present within oviductal fluid, on the modulation of sperm-oviduct adhesion in bovine species. Results showed that 1) the cell-permeant thiols (penicillamine, beta mercaptoethanol, cysteine, and dithiotreitol), as well as the nonpermeant thiol, reduced glutathione, cause adhering spermatozoa to release from the epithelium; 2) thiol action is exerted on spermatozoa; and 3) oxidized glutathione, as well as the non-thiol antioxidants (dimethylthiourea, trolox, superoxide dismutase, and catalase) have no effect. Sperm surface sulfhydryls labeled with iodoacetamide fluorescein showed that spermatozoa devoid of sulfhydryls on the head surface adhered to the fallopian epithelium in vitro, whereas thiol-induced release increased the exposure of sulfhydryls on the sperm head surface. Finally, analysis of capacitation status demonstrated that uncapacitated spermatozoa adhered to the oviduct, and that thiol-induced release of spermatozoa was accompanied by capacitation. In conclusion, thiol-reducing agents in the oviductal fluid may modulate the redox status of sperm surface proteins, leading to the release of spermatozoa selected and stored through adhesion to the fallopian tube epithelium in the bovine species.
Talevi
Riccardo
R
Dipartimento di Biologia Strutturale e Funzionale, Università di Napoli Federico II, Complesso Universitario di Monte S Angelo, 80126 Napoli, Italy. riccardo.talevi@unina.it
Zagami
Maria
M
Castaldo
Marianna
M
Gualtieri
Roberto
R
D000177:Acrosome / Q000187:drug effects; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D002478:Cells, Cultured; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005187:Fallopian Tubes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005978:Glutathione / Q000494:pharmacology; D008297:Male; D010084:Oxidation-Reduction; D019163:Reducing Agents / Q000494:pharmacology; D013075:Sperm Capacitation / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology*; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013499:Surface Properties
D019163:Reducing Agents; D013438:Sulfhydryl Compounds; D005978:Glutathione