Figure 2. Effects of GH treatment in vitro on the meiotic progress of aged oocytes. (A) Representative images of oocytes after 14 hours cultured in M2 medium (n = 87) and GH treated medium (n = 88). Black arrowheads point to oocytes that fail to extrude a polar body or fail to survive. Scale bar, 100 μm. (B) The rate of GVBD and Pb1 extrusion in these two groups respectively. (C) Left: Spindle morphologies in control and GH group. Oocytes were stained with α-tubulin (green) and hoechst (blue). Scale bar, 50 μm. Right: Percentages of oocytes with spindle defects in control (n = 51) and GH group (n = 68). Data are presented as mean ± SD. **P < 0.01.