Three-dimensional levitation culture improves in-vitro growth of secondary follicles in bovine model.

Research Question: Does a three-dimensional culture system based on magnetic levitation with nanoparticles assembly maintain the follicular structure and viability with adequate growth rates leading to oocyte maturation after long-term culture?

Design: Randomized-controlled trial of treatments in a bovine model. Secondary follicles (n = 213) isolated from bovine ovaries were cultured in a two-dimensional system (two-dimensional control) or three-dimensional levitation system with different concentrations (three-dimensional 50 µl/ml, 100 µl/ml and 200 µl/ml) of magnetic nanoparticles. Follicular growth (diameter, daily growth and growth patterns), morphology (normal, degenerated and extruded follicles), antrum formation, oocyte viability and chromatin configuration were assessed.