Fig. 1.

Effects of NMN supplementation on the maturation of heat-stressed porcine oocytes. A In vitro maturation of oocytes in control, heat-stressed (HS) and NMN-supplemented (HS + NMN) groups. Cumulus cell expansion of cumulus-oocyte complexes (COCs) and polar body extrusion (PBE) of denuded oocytes (DOs) were imaged by the confocal microscope. Scale bar, 400 μm (a, d, g); 250 μm (b, e, h); 30 μm (c, f, i). B The rates of PBE were recorded in control, heat-stressed and NMN-supplemented (10 μmol/L, 20 μmol/L, 50 μmol/L and 100 μmol/L) oocytes after culture for 44 h in vitro. Data were presented as mean percentage (mean ± SEM) of at least three independent experiments. *P < 0.05, **P < 0.01