Independent and interactive roles of hirudin and HMGB1 interference in protecting renal function by regulating autophagy, apoptosis, and kidney injury in chronic kidney disease.

Chronic kidney disease (CKD) is a progressive disorder characterized by renal fibrosis, inflammation, and dysregulated autophagy and apoptosis. High-mobility group box 1 (HMGB1) plays a crucial role in regulating autophagy in CKD. Hirudin, a potent thrombin inhibitor, has demonstrated antifibrotic and anti-inflammatory properties, but its effects on autophagy and apoptosis in CKD remain unclear. In this study, a rat model of renal interstitial fibrosis (RIF) and an HK-2 cell culture model were established to assess the effects of varying doses of hirudin and HMGB1 interference. Molecular and histological analyses, including RTqPCR, Western blot, TUNEL staining, hematoxylin-eosin (H&E) staining, immunofluorescence, and immunohistochemistry (IHC), were performed to assess renal injury, fibrosis, apoptosis, and autophagy-related markers. Hirudin treatment significantly reduced the expression of LC3, ATG12, ATG5, α-SMA, COL1A1, caspase-3, and caspase-9 while increasing P62 levels (p<0.05). It also lowered the renal coefficient (p<0.001) and apoptosis levels. The optimal effective concentration of hirudin in vitro was determined to be 4.8 ATU/mL (p<0.001). HMGB1 interference suppressed autophagy and apoptosis, as indicated by decreased LC3-II/LC3-I, ATG12, ATG5, caspase-3, and caspase-9 levels, increased P62 expression (p<0.001), and reduced apoptosis. However, simultaneous HMGB1 interference in hirudin-treated cells weakened the therapeutic effects of hirudin, leading to increased autophagy and apoptosis markers, decreased P62 levels, and a higher renal coefficient. These findings indicate that hirudin exerts protective effects in CKD by modulating autophagy and apoptosis, potentially through HMGB1 regulation. These findings highlight the therapeutic potential of targeting these mechanisms in renal dysfunction and underscore the necessity for further research to support clinical applications.