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

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 µg/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 µL 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-µg/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.

EFFECT OF PROTEIN DEFICIENCY ON PEANUT AGGLUTININ(PNA)RECEPTORS OF THYMOCYTES IN MICE / 营养学报

The change of PNA receptors on the surface of thymocytes in protein deficient mice was investigated. After the mice were fed with protein deficient diet, the body weight continuously declined and the thymus gradually a-trophied. Qualitative test of FITC-PNA indicated the number of PNA positive cells was reduced and the fluorescent antibody reaction on the surface of PNA positive cells weakened. Quantitative test of FITC-PNA showed the amount of FITC-PNA coupled on the surface of PNA positive cells was mark- edly decreased as compared with the cotrol (P