Effect of Low-Level Laser Irradiation Versus Room Temperature on Cryopreserved Sperm Motility and DNA Integrity as Modes of Thawing

During cryopreservation, cells and tissue undergo dramatic transformation in chemical and physical characteristics. Thawing process is also an important step since the cryoinjury is not limited to the freezing process but may also occur during the thawing process. Laser by its photo-stimulation effect can improve the resistance to cooled storage of some human sperm and this will lead to improvement in the quality of frozen semen and in the potential of sperm fertilization. The objective of this study is to use laser as a method of thawing and its effect on human sperm motility and DNA integrity versus the thawing through room temperature. This prospective study carried on 70 cryopreserved semen samples. Each sample was prepared by centrifugation procedure, and divided into 2 parts, freezed and thawed by laser irradiation till melting for one part and by room temperature for other. The DNA integrity and sperm motility were assessed before vitrification and after the two methods of thawing. The results of cryopreserved semen samples showed that laser irradiation thawing has significantly increased sperm motility as well as a significant decreased DNA fragmentation (P 0.05) versus room temperature thawing. Conclusion(s): Laser irradiation thawing of post freezing sperm improves post thaw motility and DNA integrity.