TIMP1 and diabetes mellitus: Diabetes also increased the levels of hydroxyproline and the expression levels of collagen Ι, collagen III, transforming growth factor β1(TGFβ1) and matrix metalloproteinase (MMP) and decreased the expression level of tissue inhibitor of matrix metalloproteinase (TIMP) in the diabetic myocardium, while exogenous H2S reversed the diabetes-induced changes, suggesting that exogenous H2S could improve myocardial fibrosis induced by diabetes.