Effects of an agarose matrix during in vitro maturation (IVM) on intra-oocyte glutathione (GSH) and reactive oxygen species (ROS) contents. Cumulus-oocyte complexes retrieved from small antral follicles were grown in vitro on the hard culture dish without an agarose matrix and then matured on the hard culture dish without (control) or with a 1% or 2% (w/v) agarose matrix. GSH and ROS contents in MII oocytes were analyzed by staining oocytes with Cell-Tracker Blue (A) and H2DCFDA (B), respectively, and determining fluorescence intensity. The GSH contents were significantly increased in the 1% (w/v) agarose matrix compared to control (C). A significant reduction of ROS contents was detected in the 1% and 2% (w/v) agarose matrix (D) compared to the control. All data are represented as the means ± SEM. a,bBars with different letters are significantly different (p < 0.05). The scale bar is 50 μm.