Advanced methods for evaluation of sperm quality

Uso do diluente água de coco em pó (ACP-103®) na conservação prolongada do sêmen do varrão: avaliação in vitro e in vivo

O sêmen de oito reprodutores foi coletado e de cada ejaculado separou-se um total de 1,75x10(9)sptz, com concentração de 35x10(6)sptz/mL. Usou-se o Beltsville Thawing Solution (BTS) como controle para testar o diluente água de coco em pó (ACP). O dia de coleta foi o dia zero (D0), sendo o sêmen conservado durante cinco dias, com análises diárias no D0 e nos quatro dias seguintes (D1, D2, D3 e D4). A avaliação da qualidade espermática baseou-se nos resultados do vigor espermático, da porcentagem de células móveis, da morfologia espermática, da integridade da membrana plasmática e dos resultados de fertilidade. As avaliações do vigor espermático (4,1) e da porcentagem de espermatozoides móveis (91%) ficaram acima dos parâmetros mínimos exigidos (3,0 e 70%) para sua utilização em programas de inseminação artificial, pois não houve influência sobre as variáveis analisadas pelo protocolo experimental. O resultado médio da resistência osmótica foi de 71,3% de espermatozoides com cauda enrolada. Não houve diferenças entre os dois diluentes testados para a característica células com acrossoma intacto (BTS = 67,1%; ACP = 71,2%). O sêmen diluído em ACP apresentou maior número de células vivas (77,7 %) com membrana plasmática íntegra (74,2%) após a conservação. A escolha do diluente ACP é aconselhável para uso de rotina em laboratórios que trabalhem com conservação de sêmen suíno. Apesar dos bons resultados in vitro obtidos com o diluente ACP, o BTS apresentou os melhores resultados de fertilidade, 86,7% e 96,7%, respectivamente.

Effects of the hypo-osmotic swelling test on the outcome of intracytoplasmic sperm injection for patients with only nonmotile spermatozoa available for injection: a prospective randomized trial

OBJECTIVE

Hypo-osmotic swelling test (HOST) has been shown to be an effective method for the selection of live sperm. On-going pregnancies were obtained by using HOST-selected sperm. The aim of this study was to evaluate the effect of using HOST-selected "live" sperm versus nonselected sperm on the outcome of intracytoplasmic sperm injection cycles when only nonmotile sperm were available for injection.

DESIGN

Prospective randomized study.

SETTING

Governmental tertiary care hospital.

PATIENT(S)

Thirty ICSI cycles with no motile sperm were included in this study.

INTERVENTION(S)

For the HOST group, potentially live spermatozoa detected by hypo-osmotic reaction of the tail were injected into oocytes. For the No-HOST group, the sperm were randomly injected into the oocytes without checking the viability.

MAIN OUTCOME MEASURE(S)

The fertilization, cleavage, embryo quality, pregnancy, and implantation rates were assessed for the two groups.

RESULT(S)

Among 30 cycles, 15 fall into each group. Fertilization, cleavage rates, and the number of good quality embryos were similar between two groups.

CONCLUSION(S)

HOST-selected live spermatozoa can be safely used for intracytoplasmic sperm injection to establish pregnancies. There is a tendency for higher pregnancy and implantation rates to result, but it does not reach statistical significance.

In vitro evaluation of frozen-thawed stallion semen: a review

The article reviews methods used for in vitro evaluation of sperm, with particular emphasis on frozen-thawed stallion sperm. The techniques, limitations of the methods and correlations with fertility results are discussed. Very few studies have tried to find correlation between fertility of frozen stallion semen and laboratory tests. It is difficult and expensive to inseminate an adequate number of mares to achieve statistically significant differences. Significant, but low correlations have been demonstrated between the foaling rate and subjective motility of sperm incubated for 2 h and 4 h at 37 degrees C and hypoosmotic swelling test after 0 and 3 h of incubation. Significant correlations have been reported between the pregnancy rate and viability of propidium iodide-stained sperm assessed by flow cytometry as well as for glass wool and Sephadex filtration tests. No correlations have been detected between fertility and motility immediately after thawing. In spite of that, motility estimation by light microscope is the most commonly used method to evaluate frozen-thawed stallion sperm. Computer assisted automatic sperm analyzers have replaced light microscopy in research projects, but so far nobody has been able to demonstrate a correlation between fertility of frozen stallion semen and any of the motility parameters obtained by these instruments.

The hypoosmotic swelling test performed with coulter counter: a method to assay functional integrity of sperm membrane in rainbow trout

The hypoosmotic swelling test (HOS) is one of the methods used to evaluate sperm quality in mammals. This test is based on the swelling ability that functional spermatozoa have when submitted to hypoosmotic solutions. Only a slight increase in size is caused in rainbow trout spermatozoa in such conditions and it is not possible to distinguish between reactive cells (cells who were capable to increase in volume) and non-reactive cells (did not increase in volume) under light microscopy. In our approach we have used the coulter counter to verify the effectiveness of the HOS test in this species. Semen was diluted in different hypoosmotic solutions (50, 100, 150, 200, 250 and 320 mosM/kg) and cell volume measured at different times after dilution (30 s, 2, 5, 10, 20, and 30 min). The higher percentage of reactive cells was achieved with the 100 mosM/kg solution and swelling occurred before 30 s. Even with this solution, the small increase in cell size caused the overlapping of volumes from swollen and non-swollen spermatozoa. In order to analyse the data and to choose a parameter suitable for assessing cell reactivity, the test was performed in samples containing known rates of live/dead cells. Two parameters were analysed after swelling: the increase in volume and the percentage of cells over a standard volume (reactive cells). Results showed a high correlation between the percentages of reactive cells and the known rate of live cells (r2 = 0.65). This fact suggests that HOS test could be used to analyse the integrity and functionality of rainbow trout fresh sperm. To study the reliability of this test in cryopreserved sperm, simple linear regressions were made between cell viability determined by Hoechst 33285 dye and the two parameters obtained from coulter counter data. No significant correlation was observed in either case, showing that structural and functional integrity do not correlate after freeze/thaw. Consistently, the HOS test is not a reliable method to evaluate cryopreserved sperm quality in rainbow trout.