title: In vitro capacitation of fresh, chilled and frozen-thawed dog spermatozoa assessed by the chloretetracycline assay and changes in motility patterns.
abstract: The effect of preservation on capacitation status of dog spermatozoa was investigated. Split ejaculates from six dogs were assessed as fresh, chilled for 24 h and rewarmed, and frozen-thawed samples. Capacitation-like status was assessed using the chlortetracycline (CTC)-assay and the measurement of sperm motility patterns using a computer-assisted sperm analyzer. Evaluations were performed on washed spermatozoa immediately after dilution in a Tris-fructose-citrate buffer (TFC) or in canine capacitation medium (CCM), and at 2-h intervals during 8 h of incubation in 5% CO2 in air, at 37 degrees C. Preservation decreased significantly the proportion of uncapacitated spermatozoa. In TFC, at hour 0, chilled-rewarmed and frozen-thawed samples had a significantly lower proportion of uncapacitated, viable spermatozoa than the fresh samples (P<0.05) according to the CTC-assay. The time course of capacitation was accelerated in the preserved samples, compared to the fresh ones. During incubation in CCM, the mean time from hour 0 to when, according to the CTC-assay, the highest proportion of capacitated spermatozoawas present in the samples (time-to-peak), was 4 h for fresh and 2 h for chilled-rewarmed and frozen-thawed samples (P<0.1). The highest values for curvilinear line velocity (VCL) and lateral head displacement (LHD), thought to be descriptive of sperm hyperactivation, were also observed 4 and 2 h after incubation began, in the fresh and the preserved samples, respectively. The difference in time-to-peak for VCL and LHD between fresh, chilled-rewarmed and frozen-thawed semen samples was statistically significant (P<0.02). It can be concluded that based on the CTC-assay and the analysis of motility patterns, capacitation-like changes in dog semen seem to be both initiated and accelerated by the preservation procedures.
authors.affiliation: Department of Obstetrics and Gynaecology, Centre for Reproductive Biology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
authors.forename: A
authors.initials: A
authors.lastname: Rota
authors.forename: A I
authors.initials: AI
authors.lastname: Peña
authors.forename: C
authors.initials: C
authors.lastname: Linde-Forsberg
authors.forename: H
authors.initials: H
authors.lastname: Rodriguez-Martinez
mesh_terms: D020101:Acrosome Reaction / Q000502:physiology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry; D006690:Bisbenzimidazole / Q000737:chemistry; D002462:Cell Membrane / Q000502:physiology; D002751:Chlortetracycline / Q000737:chemistry; D015925:Cryopreservation / Q000662:veterinary*; D004285:Dogs / Q000502:physiology*; D005456:Fluorescent Dyes / Q000737:chemistry; D008297:Male; D008856:Microscopy, Fluorescence / Q000662:veterinary; D008858:Microscopy, Phase-Contrast / Q000662:veterinary; D012662:Semen Preservation / Q000662:veterinary*; D013075:Sperm Capacitation / Q000502:physiology*; D013081:Sperm Motility / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D005456:Fluorescent Dyes; D006690:Bisbenzimidazole; D002751:Chlortetracycline