Eriocalyxin B relieves kidney damage in a rat model of membranous nephropathy by inhibiting JAK/STAT3 pathway

Purpose: To investigate the function of eriocalyxin B (EriB) in membranous nephropathy (MN) in a rat model and the related mechanisms. Methods: Cationic C-BSA was injected into Sprague-Dawley (SD) rats to generate a rat model of MN. The MN rats were treated with different concentrations of EriB (2.5, 5, and 10 mg/kg). After treatment, their kidneys were excised, sectioned, and hematoxylin and eosin (H&E) stained to determine renal injury, while Masson's trichrome staining was performed to determine renal tissue fibrosis. Bradford assay was used to determine rat proteinuria and ELISA employed to determine blood urea nitrogen (BUN) and serum creatinine (SCr) levels. ELISA was also used to measure IL-1β, IL-6, and TGF-α levels, while immunoblot analysis was used to assess protein expressions of related indicators in JAK/STAT3 pathway. Results: Compared with sham rats, MN rats showed increased the contents of proteinuria, BUN, and SCr (p < 0.01), induced serious renal injury, and increased expression of collagen I and III (p < 0.01), and fibrosis. It also elevated the levels of IL-1β, IL-6, and TGF-α (p < 0.01), causing inflammation and activation of the JAK/STAT3 pathway. EriB treatment alleviated renal injury, fibrosis, and inflammation in MN rats. With increase in EriB concentration, renal injury in MN rats was gradually alleviated. Conclusion: EriB alleviates renal injury in MN rats by inhibiting JAK/STAT3 pathway. Thus, EriB is a potential drug for the management of MN.