title: The effects of low-level laser light exposure on sperm motion characteristics and DNA damage.
abstract: The objective of this study was to determine the effects of low-level laser  light exposure on the motility of spermatozoa and on DNA damage. Thirty-three  semen samples were collected for routine analysis and were classified as  normospermic, oligospermic, or asthenospermic. After routine semen analysis  was performed, residual semen was divided into treated and control aliquots.  Treated samples were exposed to a 30-second infrared laser pulse of 50  mW/cm(2) at 905 nm, a wavelength thought to increase light-sensitive  cytochrome c oxidase in the mitochondrial electron transport chain.  Samples were then incubated at 37°C, and aliquots were analyzed at 30  minutes and 2 hours using computerassisted semen analysis. After incubation,  250 μL of each sample was frozen at 280°C until DNA fragmentation  analysis by flow cytometry. A significant increase in motility, most prominent  in oligospermic and asthenospermic samples (85% increase), was observed 30  minutes after the treatment (P < .0001). No significant increase  in DNA damage compared with control samples was observed. Significant changes  in sperm motion kinetics were observed. Low-level laser light exposure appears  to have a positive short-term effect on the motility of treated spermatozoa  and did not cause any increase in DNA damage measured at 2 hours. We conclude  that some cases of asthenospermia may be related to mitochondrial dysfunction.  The implications of this study in terms of future clinical applications needs  further investigation.
authors.affiliation: Toronto Centre for Advanced Reproductive Technology, Toronto, Ontario, Canada.
authors.forename: Ross S
authors.initials: RS
authors.lastname: Firestone
authors.forename: Navid
authors.initials: N
authors.lastname: Esfandiari
authors.forename: Sergey I
authors.initials: SI
authors.lastname: Moskovtsev
authors.forename: Eliezer
authors.initials: E
authors.lastname: Burstein
authors.forename: German T
authors.initials: GT
authors.lastname: Videna
authors.forename: Clifford
authors.initials: C
authors.lastname: Librach
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Bentov
authors.forename: Robert F
authors.initials: RF
authors.lastname: Casper
mesh_terms: D053627:Asthenozoospermia / Q000503:physiopathology; D015925:Cryopreservation; D004249:DNA Damage; D053938:DNA Fragmentation; D006801:Humans; D007259:Infrared Rays; D007834:Lasers; D008297:Male; D009845:Oligospermia / Q000503:physiopathology; D013081:Sperm Motility / Q000528:radiation effects*