Fig. 7.

Immunofluorescent detection of TOP2A in spermatozoa demonstrates the protein is associated with amorphous heads. Spermatozoa were fixed and settled onto poly-lysine slides. Following permeabilization with 0.2% Triton-X and blocking with 3% BSA, the cells were incubated with primary anti-TOP2A antibody then secondary alexafluor-488-congucated antibody and counterstained with DAPI A, (i) Phase image of spermatozoa, (ii) Immunofluorescent image using anti-TOP2A antibody fluorescence within spermatozoa, (iii) DAPI staining of spermatozoon DNA, (iv) composite image of DAPI and TOP2A fluorescence. Scale bar = 10 μm. B, Comparison of cells with detected TOP2A fluorescence between high- and low-quality cell populations (n = 3, *p = <0.0001).