The expression of TNF-α and IL-1β, major proinflammatory cytokines, was significantly increased at both the transcriptional and protein levels in the livers of AF-treated Akr1a1−/− mice compared to those of PF-treated Akr1a1−/− mice and both PF- and AF-treated WT mice (Fig. 2H, I). This evidence concerns the gene AKR1A1 and atrial fibrillation.