Fig. 5

Collagenase-treated sperm cells exhibited relatively stable motility, progressive motility, beat frequency cross and linearity within 1 h post thaw. a In contrast to control sperm cells (in gray), 2.5% glycerol cryopreserved and collagenase-treated chimpanzee spermatozoa (in black) exhibited a sharp decrease in motility at first 20 min. Similar to motility, control sperm showed a gradual decrease in progressive motility (− 29%); however, collagenase-treated sperm displayed a relatively static pattern throughout the time. b Under 7.8% glycerol preservation, collagenase-treated group (in black) showed a relatively stable pattern throughout the time when compared with control group (in gray). *Indicates significant differences between groups. Relative changes within each group (t60 vs. t10) were also indicated. Data were analyzed from 16 ejaculates from 4 individuals