Fig. 4

Analyses on cryopreserved chimpanzee spermatozoa revealed no differences between control and collagenase-treated groups. a Propidium iodine (PI) was used to quickly assess the viability of cryopreserved semen samples; alive sperm cells showed negative signal while dead sperm cells were stained in red (indicated with arrow heads). b-d Chimpanzee sperm cells treated with 0.1% collagenase showed no differences in sperm abnormality, viability, capacitation rate or acrosome integrity compared with control sperm cells after cryopreserved with either 2.5% glycerol (b-c) or 7.8% glycerol (D-E). f A slight increase in tyrosine phosphorylation was detected in collagenase-treated group when 7.8% glycerol was used for cryoprotectant. Arrowheads indicate tyrosine phosphorylated protein signals; N.S: not significantly different. At least 200 sperm cells were evaluated in each sample. Data were analyzed from 16 ejaculates from 4 individuals