Evaluation of acrosomal status and sperm viability in fresh and cryopreserved specimens by the use of fluorescent peanut agglutinin lectin in conjunction with hypo-osmotic swelling test.

Autor: Esteves SC; Androfert, Center for Male Infertility, Campinas, Sao Paulo, Brazil. s.esteves@androfert.com.br, Sharma RK, Thomas AJ Jr, Agarwal A
Jazyk: angličtina
Zdroj: International braz j urol : official journal of the Brazilian Society of Urology [Int Braz J Urol] 2007 May-Jun; Vol. 33 (3), pp. 364-74; discussion 375-6.
DOI: 10.1590/s1677-55382007000300009
Abstrakt: Objective: In this study, we evaluated whether the hypo-osmotic swelling test (HOST) can be used as a vital marker in combination with peanut agglutinin (PNA) - labeling in fresh and cryopreserved spermatozoa.
Materials and Methods: Human sperm populations were exposed to a hypo-osmotic medium for 60 minutes, and then incubated in a 1 microg/mL solution of the fluorescent dye Hoescht 33258 (H33258) for 10 minutes. Excess stain was removed by washing in phosphate-buffered saline (PBS) solution, and the pellet was resuspended in 100 microL of culture medium. Twenty microliters of this solution were subsequently smeared on a microscope slide, and fixed in ice-cold methanol to permeabilize the sperm membranes. The fixed smears were finally incubated in a 40-microg/mL FITC-PNA solution for 20 minutes. Simultaneous assessment of acrosome and viability scores was done in a fluorescent microscope equipped with appropriate filters and phase contrast illumination. The same slide was examined for FITC-PNA labeling, tail swelling, and for Hoechst-33258 staining by interchanging the filters and phase contrast optics.
Results: In fresh specimens, HOST was found to provide viability assessments comparable to those obtained using the H33258 method (r = 0.95). However, the results of HOST and H33258 were not correlated in cryopreserved specimens (r = 0.22). There was no alteration of PNA-labeling due to the HOST or H33258.
Conclusions: FITC-PNA labeling in conjunction with the visualization of the morphological change induced by exposure to hypo-osmotic solution provides a simple but effective method for establishing the state of acrosomal membrane and viability in fresh human spermatozoa, but this technique is not reliable for cryopreserved ones.
Databáze: MEDLINE