PARENT SESSION
IVF and Assisted Reproductive Technologies
515
EFFECTS OF REACTIVE OXYGEN SPECIES ON DNA STABILITY IN HUMAN SPERMATOZOA.
Kang, Hee Gyoo1,3, Kim, Dong Hoon1, Kim, Myo Kyung1, Han, Sung Won1, Lee, Ho Joon1,2, Kim, Moon Kyoo3, 1 3 2
ABSTRACT- This study was designed to investigate the effects of reactive oxygen species (ROS) on DNA stability in human spermatozoa. To verify human spermatozoa were incubated with xanthine-xanthine oxidase (X; 100uM-XO; 50 mIU ~ 400mIU), H2O2 (125uM ~ 1mM) , sodium nitroprusside (SNP; 0.1uM ~ 100 uM) or lymphocyte. Otherwise, spermatozoa were incubated under low O2 (5%) condition. Damage of sperm DNA was analyzed by single cell electrophoresis (Comet assay) and flow cytometry after acridine orange staining. In the presence of ROS, there was increase in DNA damage. The rate of DNA single strand breakage (9.0±1.0% ~ 46.0±4.6%) and DNA fragmentation (7.5±1.0% ~ 29.5±4.6%) were similar regardless of the kinds of ROS and exposure time. DNA damage in the lower O2 condition (5%) was lower than ambient O2 condition (20%). Taken together, it suggested that sperm DNA might be damaged by ROS. In the presence of ROS, increase in DNA damage and chromatin instability was obvious in spite of short exposure. Although present study reconfirmed that sperm incubation in the low concentration of ROS have the benefit in the induction of capacitation and AR, the increase in DNA damage by ROS and possible genetic problem should be considered before the human trials.
KEY WORDS: Reactive oxygen species, Human spermatozoa, DNA instability, Single cell electrophoresis