RESUMO
BACKGROUND: Renal tubulointerstitial fibrosis is a common feature of the final stage of nearly all cause types of chronic kidney disease. Although classic peroxisome proliferator-activated receptor γ (PPARγ) agonists have a protective effect on diabetic nephropathy, much less is known about their direct effects in renal fibrosis. This study aimed to investigate possible beneficial effects of lobeglitazone, a novel PPARγ agonist, on renal fibrosis in mice. METHODS: We examined the effects of lobeglitazone on renal tubulointerstitial fibrosis in unilateral ureteral obstruction (UUO) induced renal fibrosis mice. We further defined the role of lobeglitazone on transforming growth factor (TGF)-signaling pathways in renal tubulointerstitial fibrosis through in vivo and in vitro study. RESULTS: Through hematoxylin/eosin and sirius red staining, we observed that lobeglitazone effectively attenuates UUO-induced renal atrophy and fibrosis. Immunohistochemical analysis in conjunction with quantitative reverse transcription polymerase chain reaction and Western blot analysis revealed that lobeglitazone treatment inhibited UUO-induced upregulation of renal Smad-3 phosphorylation, α-smooth muscle actin, plasminogen activator inhibitor 1, and type 1 collagen. In vitro experiments with rat mesangial cells and NRK-49F renal fibroblast cells suggested that the effects of lobeglitazone on UUO-induced renal fibrosis are mediated by inhibition of the TGF-β/Smad signaling pathway. CONCLUSION: The present study demonstrates that lobeglitazone has a protective effect on UUO-induced renal fibrosis, suggesting that its clinical applications could extend to the treatment of non-diabetic origin renal disease.