Berberine attenuates lipopolysaccharide-induced extracelluar matrix accumulation and inflammation in rat mesangial cells: Involvement of NF-kappa B signaling pathway

Background: Our previous studies demonstrated that berberine could improve the renal function in rats and mice with diabetic nephropathy (DN) and inhibit extracellular matrix (ECM) component, fibronectin (FN) expression in rat mesangial cells (MCs) cultured under high glucose. However, the molecular mechanisms have not been fully elucidated. Objective: To explore the potential mechanisms of berberine in the treatment of ON, we investigated the effects of berberine on lipopolysaccharide (LPS)-induced nuclear factor-kappa B (NF-kappa B) activation and its downstream inflammatory mediators, such as intercellular adhesion molecule-1 (ICAM-1), transforming growth factor-beta 1 (TGF-beta 1), inducible nitric oxide synthase (iNOS) and fibronectin (FN) protein expression in rat MCs. Method: Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The activation of NF-kappa B was detected by Western blot and confocal microscopy. The protein levels of ICAM-1, TGF-beta 1, iNOS and FN in rat MCs were detected by Western blot. Results: Our results revealed that berberine significantly suppressed LPS-induced cell proliferation and inhibited LPS-induced NF-kappa B nuclear translocation in MCs, as well as protein expression of ICAM-1, TGF-beta 1, iNOS and FN. Conclusion: Berberine significantly repressed LPS-induced cell proliferation and FN expression in rat MCs through inhibiting the activation of NF-kappa B signaling pathway and protein expression of its downstream inflammatory mediators. The ameliorative effects of berberine on DN might be associated with this inhibition effect on NF-kappa B signaling pathway which was independent of its hypoglycemic effect. (C) 2010 Elsevier Ireland Ltd. All rights reserved.