Figure 7. DNA methyltransferase (DNMT) inhibitor 5-aza attenuated the protective role of melatonin on genomic DNA methylation in prolonged-culture oocytes. Porcine oocytes matured in vitro were continuously cultured for 24 h or in medium supplemented with 10−3 M melatonin or 10−3 M melatonin plus 1 μM 5-aza for 24 h. (A) Representative images of oocytes stained with DNMT1 antibody; (B) Quantification of DNMT1 fluorescence intensity in the prolonged-culture, prolonged-culture + Mel, and prolonged-culture + Mel + 5-aza oocytes. (C) Representative images of oocytes stained with 5mc antibody; (D) Quantification of 5mc fluorescence intensity in the prolonged-culture, prolonged-culture + Mel, and prolonged-culture + Mel + 5-aza oocytes. Scale bar, A=25 μm, B=5 μm; PC, prolonged-culture; Mel, melatonin; *P<0.05, ** P<0.01, **** P<0.0001.