To investigate the therapeutic effects of mUC-MSCs on renal fibrosis in vivo, western blotting analysis was performed to detect fibrotic factors such as TGF-β1, fibronectin, and collagen I in kidney samples from renal cortexes of mice in normal, diabetes mellitus (DM), and DM+MSC groups. This evidence concerns the gene TGFB1 and renal fibrosis.