FIGURE 8.

Aged oocytes recovery occurs when heterochromatin is enhanced: Overexpression of chromatin modifier enzymes was performed in old (9‐month‐old) prophase I‐arrested oocytes. (a) Heterochromatin recovery in EZH2 electroporated oocytes was measured by H3K27me3 staining (MW p = 0.03, 4 animals used for experiment) (b) Reduction in retrotransposon activity in treated oocytes was observed by staining for L1‐‐ORF1 (MW p = 0.03, 3 animals used for experiment). (c) Cellular functionality was measured by successful MII accomplishment in EZH2 electrporated oocytes compared with empty electroplation control. (Z test p = 0.019, 7 animals used for experiment) (d) Heterochromatin recovery in SIRT1 electroporated oocytes was measured by H3K9me2 staining (MW p = 0.0026 3 animals used for experiment). (e) Reduction in retrotransposon activity in treated oocytes was observed by staining for L1‐ORF1 (MW p = 0.0013 5 animals used for experiment). (f) Cellular functionality was measured by successful MII accomplishment in SIRT1 electrporated oocytes compared with empty electrporation control. (Z test p = 0.0086, 7 animals used for experiment) (g) Quantification of staining intensity for H3K9me2 in control old oocytes and old oocytes treated with SRT‐1720 (MW p = 0.0079) (h) Maturation efficiency of old oocytes treated with SRT‐1720 and matured in vitro was measured by proportion of oocytes which succeed to complete MI after treatment. (Z test p = 0.0078, animals used for experiment N = 6). As above, since incubation with the drug required longer IVM incubation than normal, an extended incubation without SRT‐1720 was also added as control