However, another study constructed S100a9-/- mice and S100a9Tg mice, and confirmed that compared to WT mice, the myocardial fibrosis area and myocardial contraction dysfunction of S100a9-/- mice after MIR were significantly reduced, and the results observed in S100a9Tg mice were completely opposite 28. This evidence concerns the gene S100A9 and Myocardial fibrosis.