Study on the Mechanism of Cathepsin L on the Activation of M1 Macrophages in Sepsis-induced Acute Renal Injury

The purpose of this study was to explore the mechanism of cathepsin L and M1 macrophages in acute renal injury induced by sepsis. The sepsis model of male mice was established by cecal ligation puncture or sham operation, and the biochemical and histological renal damage in mice was evaluated. At the same time, infiltration of macrophages was detected by immunohistochemistry. The expression of cathepsin L-inducible nitric oxide synthase and argininase 1 messenger ribonucleic acid was analysed by reverse transcription polymerase chain reaction. Western blotting was used to detect the expression level of cathepsin L. High level of cathepsin L was detected 24 h after sepsis-induced acute renal injury. The results of the western blot assay showed that cathepsin L inhibitors successfully inhibited the expression of cathepsin L during the sepsis-induced acute renal injury. After the establishment of the septic-induced acute renal injury model, cathepsin L inhibitors alleviated the renal injury, while M1 macrophage activation was significantly inhibited. In sepsis-induced acute renal injury, cathepsin L plays an important role in related initial inflammatory response by activating M1 macrophages.