As shown in Figures 5(f)–5(i), the mRNA levels of Dnmt1 (P < 0.05) and Dnmt3b (P < 0.01) were elevated in CF hearts, and the H-DHI treatment significantly downregulated mRNA levels of Dnmt1 (P < 0.01) and Dnmt3b (P < 0.05). Here, DNMT1 is linked to cystic fibrosis.