Figure 3. Acrosomal membrane damage of the rat sperm head.

(A) Spermatozoa were sonicated to separate head and tail. Acrosome and nucleus of sperm head were stained with green (FITC-PNA) and red (PI), respectively. Acrosomal membrane remains “intact” or “damaged”. Bar = 5 µm. (B) Sperm heads that were not heat-dried (control) or heat-dried were randomly counted. Experiments were repeated separately four times using 20 sperm heads per replicate. The values are expressed as mean ± SEM. Values with different letters within each category differ significantly (P<0.05).