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 37uC, and aliquots were analyzed at 30 minutes and 2 hours using computerassisted semen analysis. After incubation, 250 mL of each sample was frozen at 280uC 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.

Red light improves spermatozoa motility and does not induce oxidative DNA damage

“…These methods are not always successful and could benefit from additional means of improving fertilization. Several studies have indicated that low doses of red light cause an increase in sperm motility and overall fertilizing potential in several species1234. By increasing sperm swimming speed in vitro , the likelihood of contact with the oocyte is increased.…”

“…However, DNA damage was not tested in this the study. Several studies235 have also used the well-known computer-assisted sperm analysis (CASA) system for measurement of sperm motility by measuring swimming speed directly after light irradiation. Such studies assume that optically induced effects last several minutes following irradiation.…”

“…Firestone et al . found that 30 seconds of irradiation with 905 nm light did not result in significant levels of DNA fragmentation as measured using acridine orange2. This method distinguishes single-stranded from double-stranded DNA based on fluorescence emission of sperm that have been acid treated.…”

Experimental justification of laser therapy efficiency of men's infertility

“…Более того, есть вполне убедительные дока-зательства, что низкоинтенсивный, как лазерный, так и некогерентный, свет позволяет существенно повысить выживаемость, подвижность и скорость перемещения сперматозоидов человека [52][53][54][55].…”

“…Лишь в одной работе использовали импульсный ИК-лазер (длина волны -905 нм) мощностью 50 Вт (длительность импульса -200 нс), плотность мощ-ности -50 Вт/см 2 , причем даже при далеко неопти-мальной (мягко говоря) частоте 10 000 Гц наблюдали повышение подвижности и отсутствие повреж-дений ДНК. Вероятно, положительный результат был получен вследствие небольшой экспозиции (30 с), причем он отсутствовал при нормо-и асте-носпермии, а наблюдался, и весьма значительный (в 8,4 раза), только при олигоастенотератозооспер-мии через 30 мин после лазерного освечивания [55]. Это подтверждает известное мнение, что степень влияния НИЛИ коррелирует с выраженностью имеющихся нарушений [31].…”