In addition, Yan et al. found that MicroRNA let-7a was down expressed in both DKD rats and 293T mesangial cells under high glucose conditions, naringenin can inhibit TGF-β1/Smad signaling pathway by increasing the expression of MicroRNA let-7a, repressing glomerular mesangial cells proliferation and accumulation of ECM, thereby preventing renal fibrosis [119]. This evidence concerns the gene TGFB1 and renal fibrosis.