In the rat model of adenine-induced chronic tubular injury, administration of ursolic acid (30 mg/kg Body weight) for 28 days inhibited the activation of TGF-β/Smad signaling and in turn reduced extracellular matrix (ECM) proteins such as fibronectin (FN) and collagen, suppressing the development and progression of renal fibrosis [140]. This evidence concerns the gene FN1 and renal fibrosis.