title: Leptin and leptin receptor are detectable in equine spermatozoa but are not involved in in vitro fertilisation.
abstract: In human and swine, leptin (OB) has been identified in seminal plasma and leptin receptors (OB-R) on the cell surface of spermatozoa, indicating that spermatozoa are a target for OB. This hormone has also been detected in follicular fluid (FF) in women and mares, although its role requires further study. The aims of this study were to investigate the immunolocalisation and the expression of OB and OB-R in equine spermatozoa and to evaluate the involvement of OB in equine in vitro fertilisation (IVF). Since progesterone (P) and OB are both found in FF, the individual and combined effects of these two hormones were studied in equine IVF and compared with the results obtained from the use of FF for in vitro sperm preparation. For the first time, we were able to identify OB and OB-R mRNA and their corresponding proteins in equine spermatozoa. When spermatozoa were treated with OB, there was a decrease in the three motility parameters VSL, STR and LIN, commonly associated with hyperactivation, whilst the acrosome reaction rate increased (P<0.05). The fertilisation rate was 51% with FF, 46.15% with P, 43.64% with P+OB and 0% with OB alone. The percentage of eight-cell stage embryos was 18.7% with FF, 17.1% with P and 16.7% with OB+P. OB alone did not permit oocyte fertilisation, indicating that, in the horse, OB is involved in capacitation and hyperactivation but not in sperm penetration.
authors.affiliation: Large Animal Hospital, Reproduction Unit, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Lange-Consiglio
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: Bruna
authors.initials: B
authors.lastname: Corradetti
authors.affiliation: Large Animal Hospital, Reproduction Unit, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Perrini
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Bizzaro
authors.affiliation: Large Animal Hospital, Reproduction Unit, Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy.
authors.forename: Fausto
authors.initials: F
authors.lastname: Cremonesi
mesh_terms: D020101:Acrosome Reaction; D000818:Animals; D017209:Apoptosis; D002470:Cell Survival; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D015571:Follicular Fluid / Q000378:metabolism; D006736:Horses; D020738:Leptin / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism*; D013075:Sperm Capacitation; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
chemical_list: D020738:Leptin; D054411:Receptors, Leptin; D011374:Progesterone