In the rat model of myocardial fibrosis induced by thyroid hormone, miR-34a expression and PI3K and Akt proteins were found to be upregulated, while autophagy related proteins (ATG5, Atg7, Atg16L1, Beclin1, LC3A) were significantly downregulated, and MMPs/TIMPs ratios appeared imbalance. This evidence concerns the gene AKT1 and Myocardial fibrosis.