Received April 11, 2008
Accepted April 25, 2008

Introduction:The technique of oocytes cryopreservation is a helpful tool for assisted reproduction as it can be used to preserve female reproductive capacity. Objective: To determine the effectiveness of trehalose as intracellular cryoprotectant in the vitrification of bovine oocytes matured in vitro. Methods: The groups were controlled (Tc, Tp and Tm) and groups for vitrification (Tmv - microinjected with trehalose, Tvde - with penetrating crioprotectant and Tev-lectropermeabilizations with trehalose). After thawing we evaluated the capacity of cytoplasmic re-expansion, the integrity of membrane (marking with propidium iodide) and glycoprotein alterations of the pellucid zone (with lectins conjugated with fluorescein 5- isotiocianato FITC). Results: The evaluation of the tax of return to the isotonic volume after thawing showed a superior result for the eletroporation oocyte with trehalose (80%). Oocytes of the treatments Tmv and Tev presented indices of 55 and 68%, respectively. In the same way the oocytes of the treatment Tev were the ones that presented low cytoplasmic drawing tax (13%). However the evaluation of the integrity of membrane, determined for the exclusion of the IP, resulted in absence of marking in 36%, 64% and 29% of the oocytes of the treatments Tmv, Tvde and Te, respectively. The marking of residues of manose and sialic acid of the surface of the pellucid zone of the oocytes after thawing did not present difference between the treatments, having all presented 100% of marking. Conclusion: These results demonstrate that intracellular trehalose presents an important effect crioprotectant for the vitrification of bovine oocytes matured in vitro.