Figure 1.

Membrane-bound RAGE is a stable marker of low-quality sperm. (a) RAGE localization at the acrosome and equatorial band on the sperm cell head as shown by confocal microscopy. (b and c) Line-graph showing the proportion of IM sperm (analysed using CASA) and sperm expressing RAGE (analysed using flow cytometry) in (b) neat (washed) sperm and (c) DGC purified spermatozoa when incubated over 72 h, n = 6; % mean ± SEM. (d and e) Representative flow cytometry data showing RAGE expression in (d) DGC purified and (e) neat washed spermatozoa over time (0–72 h). (f and g) Proportion of (f) sperm expressing RAGE as measured by flow cytometry and (g) PR sperm as measured by CASA in neat washed sperm and the pellet (low-quality) and supernatant (high-quality) fractions of the swim-up purification, n = 15; % mean ± SEM. One-way ANOVA; **P < 0.01, ***P < 0.001, ****P < 0.0001. IM, immotile sperm; CASA, computer-assisted semen analysis; DGC, differential gradient centrifugation; PR, progressively motile sperm.