Lindera aggregata intervents adenine-induced chronic kidney disease by mediating metabolism and TGF-β/Smad signaling pathway

Introduction: Lindera aggregata is a main Chinese herb of ancient prescriptions Suoquan pill applied for treating the chronic kidney disease (CKD). A large number of application histories of Lindera aggregata in the treatment of CKD have been recorded in Chinese traditional medical literature. The previous reports revealed that Lindera aggregata can treat CKD.

Methods: Rats were randomly divided into control, model, Huangkui,Lindera aggregata ethanol extract (LEE) and Lindera aggregata water extract (LWE) groups. hematoxylin-eosin (HE) staining was used to detect the pathology of kidney. The levels of serum creatinine (Scr), serum Neutrophil gelatinase-associated lipocalin (NGAL), blood urea nitrogen (BUN), urine protein (UP), kidney index(KI) were evaluated. The UPLC - QTOF/MS were applied to probe the metabolic profile. Furthermore, Indoxyl sulfate-induced human renal tubular epithelial (HK-2) cell model was built to determine the expression levels of pathogenesis-related proteins.

Results: The results demonstrated that LEE and LWE significantly inhibited the rebound in Scr, BUN, NGAL, UP and KI in models, except for the effect of LWE at low dose (LWE-L) and LEE at low dose (LEE-L) on KI and the effect of LWE-H at high dose (LWE-H) and LEE-L on BUN and NGAL. Moreover,Lindera aggregata extracts alleviated renal tubular dilatation, interstitial fibrosis and interstitial inflammation. By analysis, twenty-eight metabolites were related to CKD. After intervention of Lindera aggregata extracts, some metabolites approach to a normal-like level, such as Indoxyl sulfate. These metabolites are mainly involved in tryptophan, fatty acid, glycerophospholipid, tyrosine and arachidonic acid metabolic pathways. Furthermore, Lindera aggregata extracts mediate the expression of smad2, smad3, smad7 and TGF-β in Indoxyl sulfate-induced HK-2 cell.

Conclusions: Lindera aggregata extracts can mitigate adenine-induced CKD by modulating the metabolic profile and TGF-β/Smad signaling pathway, providing important supports for developing protective agent of Lindera aggregata for CKD.