Objectives. Cryopreservation of semen is associated with reduced motil
ity after thawing, resulting in a decreased pregnancy rate. Artificial
stimulation of motility has been used in fresh semen samples. This st
udy measured the effect of motility stimulants on various motion chara
cteristics and other sperm functions using cryopreserved semen. Method
s. Frozen semen samples from healthy donors were thawed, and motility
stimulants were added in vitro and incubated for 60 minutes. The perce
ntages of motile spermatozoa in each specimen and other motion charact
eristics were measured. In addition, spermatozoon's viability, membran
e integrity, and ability to penetrate bovine cervical mucus were studi
ed after addition of stimulants. Results. Percentage motility and all
other motion characteristics improved after stimulation with pentoxify
lline, caffeine, or 2-deoxyadenosine. Linearity did not significantly
differ in the control samples after adding any of the stimulants. Viab
ility, membrane integrity, and penetration ability did not improve sig
nificantly and were comparable with control values. Conclusions. Pento
xifylline, caffeine, and 2-deoxyadenosine can stimulate sperm motility
and other motion characteristics. This may be beneficial in the cryop
reservation of sperm from normal donors and oligozoospermic patients f
or use in assisted reproduction.