[Investigating mechanism of salt-fried processed Plantaginis Semen active component calceolarioside B in intervening lipid peroxidation metabolic pathway to exert anti-renal fibrosis effects].

Abstract

This study employed an MCnebula-driven metabolomics approach to investigate the key biomarkers and metabolic pathways involved in the regulation of renal fibrosis by calceolarioside B. In a rat model of adenine-induced renal fibrosis, calceolarioside B was observed to significantly reduce serum creatinine and blood urea nitrogen levels. Western blot analysis showed that it markedly decreased the expression of fibrosis markers, including fibronectin(FN), hypoxia-inducible factor-1α(HIF-1α), and α-smooth muscle actin(α-SMA), in renal tissue. In vitro, calceolarioside B significantly inhibited the expression of FN, HIF-1α, vimentin, and α-SMA in transforming growth factor-β(TGF-β)-stimulated rat renal tubular epithelial cells(NRK-52E) and rat renal fibroblasts(NRK-49F). Metabolomics analysis showed that calceolarioside B significantly restored the levels of 47 serum metabolites in rats with renal fibrosis. Specifically, the content of fatty acids(e.g., N-acyl amides, and long-chain fatty acids) was increased, while that of lipids(lysophosphatidylcholine, phosphoethanolamine, and phosphatidylethanolamine) was decreased--a profile consistent with ACSL4-driven lipid peroxidation pathway. Based on these findings, key proteins and metabolites downstream of the lipid metabolism pathway were further validated. The results showed that, compared with the control group, rats with renal fibrosis exhibited significantly elevated serum levels of malondialdehyde(MDA), tumor necrosis factor-α(TNF-α), and interleukin-1β(IL-1β), while glutathione peroxidase 4(GPX4) and glutathione/oxidized glutathione(GSH/GSSG) were markedly reduced. calceolarioside B reversed these changes. In summary, these findings indicate that calceolarioside B can correct lipid metabolism abnormalities in the serum of rats with renal fibrosis by inhibiting the ACSL4-mediated lipid peroxidation pathway. Moreover, it can alleviate oxidative stress and inflammatory responses by activating the System Xc~--GSH-GPX4 antioxidant system, thereby ameliorating renal fibrosis.