Figure 2. The in vitro oocyte maturation of aged mice. (A) The in vitro maturation of oocytes of aged mice and young mice and the effect of sorbinil as an inhibitor of AR. The red arrows in the images identify oocytes that extruded the first polar body (PB). (B) The first polar body extrusion in aged oocytes (aged) was increased by sorbinil. Each group had at least 20 oocytes. (C) The level of sorbitol in aged IVM oocytes was significantly higher than that in young IVM oocytes (n = 50). The level of sorbitol in aged IVM oocytes was decreased by sorbinil (sorbinil), suggesting the inhibitory effect of sorbinil on sorbitol accumulation. All experiments were repeated at least three times. Scale bar = 50 μm, *P < 0.05, **P < 0.01.