Influência da cinética espermática sobre a taxa de prenhez na inseminação artificial em tempo fixo em bovinos / Influence of sperm kinetics on pregnancy rate in fixed-time artificial inseminations in cattle

The aim of the study was to evaluate the influence of hyperactivated sperm kinetics on pregnancy rate in IATF. Two experimental groups were established, based on the results of the semen analysis in the CASA system: groups of bulls with hyperactivated sperm (N = 10; HIPER) and bulls with non-hyperactivated sperm (N = 14; N HIPER). Differences between groups were estimated by the t test, and a significance level <5% was considered. Highervalues for the variables were identified in the HIPER group: VAP; VSL; VCL; ALH; RAPID cells and SLOW cells. On the other hand: BCF; STR; LIN; WOB and MEDIUM cells, which had higher values in the N HIPER group. No difference was found for the pregnancy rate variable between groups (p=0.454). Therefore, although the CASA system is an objective method of analysis, we can consider that it alone is not sufficient to predict seminal fertility, but when associated with other techniques such as: specific software and multivariate statistics that identify subpopulations, if makes it an important methodology for assessing semen quality.

Características do comportamento hiperativado de espermatozoides de felinos domésticos / Characteristics of the cat sperm hyperactivated behavior

Sperm hyperactivity is a physiological behavior, and in the feline species it is characterized by an increase in the curvilinear velocity (VCL) and a greater head beat (ALH) evaluated by the CASA system. The study aimed to compare and correlate kinetic parameters of Hyperactive and Non-Hyperactive feline ejaculates when considering the means of VCL and ALH. Ejaculates were collected by electro ejaculation from 21 cats. The seminal samples had the kinetic parameters evaluated by the CASA system. From the average values of VCL and ALH, the ejaculates were classified in group HP (Hyperactivated, when VCL>190.17µm/s and ALH>6.44µm) and NHP (Non-Hyperactivated, when VCL<190.17 and ALH<6.44 µm). A T test and Pearson's correlation were performed with a significance of p<0.05. Among the groups, were detected higher values of total (HP: 68,2% vs NHP: 35,9%) and progressive (HP:40,1% vs NPH: 17,18%) motility, VAP (HP: 165,85µm/s vs NHP: 97,72 µm/s), VSL (HP:137,63µm/s vs NHP 82,6µm/s), VCL (HP: 237,31µm/s vs NHP: 147,94µm/s) and ALH (HP: 7,28µm vs NHP:5,42µm) for the HP group. There was a correlation in the HP ejaculates between total and progressive motility. In the NHP group, a correlation was observed between motility and progressive motility, and between progressive motility and STR and LIN. It was concluded that HP spermatozoa have a higher curvilinear speed, while NHP spermatozoa stand out due to their straight path.

Influência da cinética espermática sobre a taxa de prenhez na inseminação artificial em tempo fixo em bovinos / Influence of sperm kinetics on pregnancy rate in fixed-time artificial inseminations in cattle

The aim of the study was to evaluate the influence of hyperactivated sperm kinetics on pregnancy rate in IATF. Two experimental groups were established, based on the results of the semen analysis in the CASA system: groups of bulls with hyperactivated sperm (N = 10; HIPER) and bulls with non-hyperactivated sperm (N = 14; N HIPER). Differences between groups were estimated by the t test, and a significance level <5% was considered. Highervalues for the variables were identified in the HIPER group: VAP; VSL; VCL; ALH; RAPID cells and SLOW cells. On the other hand: BCF; STR; LIN; WOB and MEDIUM cells, which had higher values in the N HIPER group. No difference was found for the pregnancy rate variable between groups (p=0.454). Therefore, although the CASA system is an objective method of analysis, we can consider that it alone is not sufficient to predict seminal fertility, but when associated with other techniques such as: specific software and multivariate statistics that identify subpopulations, if makes it an important methodology for assessing semen quality.(AU)

Características do comportamento hiperativado de espermatozoides de felinos domésticos / Characteristics of the cat sperm hyperactivated behavior

Sperm hyperactivity is a physiological behavior, and in the feline species it is characterized by an increase in the curvilinear velocity (VCL) and a greater head beat (ALH) evaluated by the CASA system. The study aimed to compare and correlate kinetic parameters of Hyperactive and Non-Hyperactive feline ejaculates when considering the means of VCL and ALH. Ejaculates were collected by electro ejaculation from 21 cats. The seminal samples had the kinetic parameters evaluated by the CASA system. From the average values of VCL and ALH, the ejaculates were classified in group HP (Hyperactivated, when VCL>190.17µm/s and ALH>6.44µm) and NHP (Non-Hyperactivated, when VCL<190.17 and ALH<6.44 µm). A T test and Pearson's correlation were performed with a significance of p<0.05. Among the groups, were detected higher values of total (HP: 68,2% vs NHP: 35,9%) and progressive (HP:40,1% vs NPH: 17,18%) motility, VAP (HP: 165,85µm/s vs NHP: 97,72 µm/s), VSL (HP:137,63µm/s vs NHP 82,6µm/s), VCL (HP: 237,31µm/s vs NHP: 147,94µm/s) and ALH (HP: 7,28µm vs NHP:5,42µm) for the HP group. There was a correlation in the HP ejaculates between total and progressive motility. In the NHP group, a correlation was observed between motility and progressive motility, and between progressive motility and STR and LIN. It was concluded that HP spermatozoa have a higher curvilinear speed, while NHP spermatozoa stand out due to their straight path.(AU)

Cyclic nucleotide phosphodiesterase inhibition increases tyrosine phosphorylation and hyper motility in normal and pathological human spermatozoa

Our objective was to determine the effect of phosphodiesterase (PDE) inhibition on: 1) tyrosine phosphorylation of human spermatozoa at the tail level; and 2) sperm motion parameters and hyperactivated motility. The study was conducted with normozoospermic and asthenozoospermic samples incubated under in vitro capacitating conditions. The main outcome measures were computer-assisted sperm motion analysis and fluorescent immunodetection of phosphotyrosine-containing proteins. Pentoxifylline (PTX) was used as PDE inhibitor because of its wide use in the clinic. PTX-treatment significantly increased sperm velocity, hyperactivated motility and tyrosine-phosphorylation, both in normo and asthenozoospermic samples. Tyrosine-phosphorylation of tail proteins was highly conspicuous in both types of samples, showing no differential pattern after PTX-treatment. Normozoospermic samples treated with pentoxifylline showed an increase in the number of spermatozoa displaying hyperactivated movement and tyrosine-phosphorylation at the tail level. Preliminary data on asthenozoospermic samples exhibiting altered motion characteristics and defective phosphorylation of sperm-tail proteins showed that both defects can be concomitantly overcome by pentoxifylline treatment. Tyrosine-phosphorylation of sperm-tail proteins is underlying the enhancement of hyperactivated motility resulting from PDE inhibition by pentoxifylline.