Abstract
The prevalence of chronic kidney disease (CKD) in dogs increases with age, and renal fibrosis is an important pathophysiological mechanism in this process. However, only a few drugs that can effectively inhibit fibrosis in the kidneys of dogs are currently available. In this study, we aimed to determine whether pirfenidone, a drug that has shown antifibrotic effects in various clinical studies, also exerts antifibrotic effects on canine renal tubular epithelial cells, Madin-Darby canine kidney cells (MDCK). To this end, we treated MDCK cells with various concentrations of pirfenidone, followed by transforming growth factor-beta1 (TGF-β1) to stimulate fibrotic conditions. A cell viability assay was performed to determine the effect of pirfenidone on cell survival. Fibrosis-related markers and TGF-β1 fibrotic pathway-related markers were assessed using qPCR, Western blot analysis and immunocytochemistry. A one-way analysis of variance (ANOVA) was performed, followed by Tukey's post-hoc test for multiple comparisons. Pirfenidone treatment significantly reduced the expression of profibrotic markers such as α-smooth muscle actin, fibronectin, and collagen. Additionally, it upregulated the expression of E-cadherin, an epithelial marker. Furthermore, pirfenidone effectively inhibited the phosphorylation of key factors involved in the TGF-β1 signaling pathway, including Smad2/3 and ERK1/2. These results demonstrate that pirfenidone suppresses TGF-β1-induced fibrosis in MDCK cells by attenuating epithelial-mesenchymal transition and the relevant signaling pathways.