TIMP1 and renal fibrosis: Renal fibrosis caused by TGF-β1 is mainly manifested in the following aspects: it can stimulate fibroblasts and other factors to increase ECM component synthesis; by inhibiting the activities of various ECM degrading enzymes (MMPs) and plasminogen activator, and stimulating the activities of tissue inhibitor of metalloproteinase-1 (TIMPS) and plasminogen activator-1 (PAI-1), ECM degradation is inhibited.