Full text
| |
| Author(s): |
André Furugen Cesar de Andrade
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2009-03-13 |
| Examining board members: |
Rubens Paes de Arruda;
Eneiva Carla Carvalho Celeghini;
Ed Hoffmann Madureira;
Rodrigo Costa Mattos;
Frederico Ozanam Papa
|
| Advisor: | Rubens Paes de Arruda |
| Field of knowledge: | Agronomical Sciences - Veterinary Medicine |
| Indexed in: | Banco de Dados Bibliográficos da USP-DEDALUS |
| Location: | Universidade de São Paulo. Biblioteca da Faculdade de Medicina Veterinária e Zootecnia |
| Abstract | |
Cryopreservation of equine spermatozoa leads to capacitation-like changes (cryocapacitation). Seminal plasma contains decapacitating factors. Moreover, it has been known that addition of seminal plasma from stallions with good post-thaw semen quality to semen of stallions with low post-thaw semen quality preserve progressive motility and membrane integrity better. Therefore, this study was intended to find out whether the cryopreservation process induces capacitation-like changes and if addition of autologous seminal plasma or seminal plasma from stallion with good post-thaw semen quality (homologous) reduces cryocapacitation effects. For this, five ejaculates were obtained from each of four mature stallions. Samples of in natura semen were analyzed, and submited to cryopreservation. Post-thawed semen was analyzed again so divided in three treatments: only cryopreservation media without cryoprotectants, cryopreservation media without cryoprotectants added 20 % (v/v) of seminal plasma homologous, and cryopreservation media without cryoprotectants added 20 % (v/v) of seminal plasma autologous. All samples were maintained in water bath (37°C) for 120 minutes, while semen analyzes were assessed at time 0, 60 and 120 min. The assessment of each sample was determined by computer-assisted sperm analyses of motility (CASA) and flow cytometry analyzes of acrosome reaction, mitochondrial potential, increased membrane fluidity, lipid peroxidation and degree of protein tyrosine phosphorylation in sperm surface. The variables were submitted to analysis of variance and LSD test at 5% level of significance. Cryopreservation did not increase viable cells with acrosome reaction, neither viable cells with increased membrane fluidity (capacitated). However, cryopreservation led an decrease of cell with mitochondrial potential and an increased in lipid peroxidation, besides increase tyrosine phosphorylation of the equine sperm surface proteins. The cryopreservation caused a reduction of all variables assessed by CASA, including hyperactivated cells. Seminal plasma addition, regardless of origin, improved integrity of plasma membrane, reduced number of viable cells with increased membrane fluidity, besides decrease phosphorylation of sperm surface proteins. Nevertheless, the improved created only was found in the initial analysis (time 0), seminal plasma shown a harmful effect in maintenance of sperm during incubation. Incubation of sperm in seminal plasma damaged majority of variables assessed. Based on results, seminal plasma could be added to post-thawed semen to decrease the cryocapacitation effects. However, post-thawed semen has to be deposited as soon as possible in female reproductive tract when the seminal plasma is added. (AU) | |