CCL2 and renal fibrosis: In high-fat diet and STZ-induced DN rats, berberine and Tangshen Formula can not only inhibit the up-regulation of IL-1β, TNF-α, and CCL2 by inactivating the NF-κB signaling pathway, but also attenuate renal fibrosis via the TGF-β/Smad3-mediated signaling pathway [50,51,52].