title: The effect of low-level laser irradiation on sperm motility, and integrity of the plasma membrane and acrosome in cryopreserved bovine sperm.
abstract: Freezing changes sperm integrity remarkably. Cryopreservation involves cooling, freezing, and thawing and all these contribute to structural damage in sperm, resulting in reduced fertility potential. Low-level laser irradiation (LLLI) could increase energy supply to the cell and cause reactive oxygen species reduction (ROS), contributing to the restoration of oxygen consumption and adenosine triphosphate synthesis (ATP) in the mitochondria. Our goal was to analyze the effects of low-level laser irradiation on sperm motility and integrity of the plasma membrane and acrosome in cryopreserved bovine sperm.
  
  
  
  We analyzed 09 samples of bull semen (Bos taurus indicus), divided into three groups: a control group without laser irradiation, a 4J group subjected to a laser irradiation dose of 4 joules, and a 6J group subjected to dose of 6 joules. Samples were divided for the analysis of cell viability and acrosomal membrane integrity using flow cytometry; another portion was used for motion analysis. Irradiation was performed in petri dishes of 30 mm containing 3 ml of semen by an aluminum gallium indium phosphide laser diode with a wavelength of 660 nm, 30 mW power, and energy of 4 and 6 joules for 80 and 120 seconds respectively. Subsequently, the irradiated and control semen samples were subjected to cryopreservation and analyzed by flow cytometry (7AAD and FITC-PSA) using the ISAS--Integrated Semen Analysis System.
  
  
  
  Flow cytometry showed an increase in the percentage of live sperm cells and acrosome integrity in relation to control cells when subjected to irradiation of low-power laser in two different doses of 4 and 6 joules (p < 0.05). In the analysis of straightness, percentage of cell movement, and motility, a dose of 4 joules was more effective (p < 0.05).
  
  
  
  We conclude that LLLI may exert beneficial effects in the preservation of live sperm. A dose of 4 joules prior to cryopreservation was more effective than a dose of 6 joules in preserving sperm motility.
authors.affiliation: Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Guilherme Henrique C
authors.initials: GH
authors.lastname: Fernandes
authors.affiliation: Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil; Postgraduate Program in Biophotonics, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Paulo de Tarso Camillo
authors.initials: Pde T
authors.lastname: de Carvalho
authors.affiliation: Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Andrey Jorge
authors.initials: AJ
authors.lastname: Serra
authors.affiliation: Postgraduate Program in Veterinary Medicine-Universidade de Santo Amaro (UNISA) São Paulo, São Paulo, SP, Brazil.
authors.forename: André Maciel
authors.initials: AM
authors.lastname: Crespilho
authors.affiliation: Instituto de Ciências Biomédicas da Universidade de São Paulo-USP-São Paulo, São Paulo, SP, Brazil.
authors.forename: Jean Pierre Schatzman
authors.initials: JP
authors.lastname: Peron
authors.affiliation: Instituto de Ciências Biomédicas da Universidade de São Paulo-USP-São Paulo, São Paulo, SP, Brazil.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Rossato
authors.affiliation: Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil; Postgraduate Program in Biophotonics, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Ernesto Cesar Pinto
authors.initials: EC
authors.lastname: Leal-Junior
authors.affiliation: Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil; Postgraduate Program in Biophotonics, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Regiane
authors.initials: R
authors.lastname: Albertini
mesh_terms: D000177:Acrosome / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism*; D002470:Cell Survival / Q000528:radiation effects; D015925:Cryopreservation; D005434:Flow Cytometry; D007834:Lasers; D008297:Male; D012662:Semen Preservation; D013081:Sperm Motility / Q000528:radiation effects*