The obtained results indicated that hUCMSCs-Exo@Ex-4 reduced blood glucose and proteinuria production to effectively ameliorate kidney injury in DN mice, as manifested by attenuation of glomerular and interstitial fibrosis and thickened glomerular basement membrane and decreased expression of inflammatory cytokines IL-6 and TNFα and chemokines CCL2 and CXCL10. This evidence concerns the gene CCL2 and liver dysplastic nodule.