Furthermore, H2S is believed to counteract thyroxine-induced myocardial fibrosis by inducing autophagy, mediated by increased activity of the PI3K/AKT signaling axis and the simultaneous downregulation of microRNAs miR-21, miR-34a, and miR-214 [99] (Figure 3). This evidence concerns the gene AKT1 and Myocardial fibrosis.