THE EFFECT OF HELIUM-NEON LASER IRRADIATION ON IN-VITRO MATURATION AND FERTILIZATION OF IMMATURE BOVINE OOCYTES

A study was made of the effects of low power laser irradiation on in v itro oocyte maturation rates and subsequent fertilization of immature bovine oocytes. Immature bovine oocytes from cows sacrificed at a slau ghterhouse were irradiated with Helium-Neon laser (HeNe laser) irradia tion at an energy density of 0.4 and 2.0 J cm(-2). An oocyte group was left untreated, serving as control group. All oocytes were matured an d fertilized in TCM-199 medium supplemented with 20% fetal calf serum (FCS). Maturation and fertilization rates obtained in the irradiated o ocytes group were lower (p<0.001 and p<0.05, respectively) than those of the control group. Furthermore, the laser-treated oocytes showed im portant degenerative changes on both cytoplasm and chromosomes in comp arison with untreated control oocytes which showed a homogenous cytopl asm and disperse chromosomes. It is concluded that the application of HeNe laser irradiation at 0.4 and 2.0 J cm(-2) energy densities has a detrimental effect on in vitro maturation and fertilization process of immature bovine oocytes.