Citotoxicidade da suplementação de β-NGF no meio de maturação ovocitária da produção in vitro de embriões bovinos

Abstract

The in vitro production of embryos (IVP) has already been a widely used technique in Brazil applied to animal reproduction, standing out in the evolution of efficiency in cattle farming. However, this biotechnology still has low efficiency in the utilization of oocytes and, therefore, needs to be improved. There are already studies that have verified positive effects of supplementation with 100 ng/ml of the β-NGF protein in the in vitro oocyte maturation (IVM) medium. However, on the other hand, there are studies that demonstrate possible cytotoxic effects with supplementation of 500 ng/ml of β-NGF protein in the same medium. Therefore, it is still necessary to determine the ideal dosage of β-NGF in the maturation medium. The present study aims to determine from which concentration β-NGF is cytotoxic to oocytes and cumulus cells through the production of reactive oxygen species (ROS). The cytotoxicity of β-NGF was evaluated in cumulus-oocyte complexes (COCs), and the concentrations of 50 ng/ml, 100 ng/ml, 200 ng/ml, 350 ng/ml, 500 ng/ml, and 1000 ng/ml were tested in the IVM medium. For the evaluation of cytotoxicity, the COCs were analyzed under an EVOs microscope with staining for reactive oxygen species (ROS). The highest concentration that is not worse than the values of the control group would, theoretically, be the most suitable to be used in IVP routines. It was possible to observe that concentrations up to 200 ng/mL do not show a statistically significant difference compared to the control group, thus being the highest concentration that still causes beneficial effects without resulting in a significant increase in ROS