Kazinol B alleviates hypoxia/reoxygenation-induced hepatocyte injury by inhibiting the JNK signaling pathway.

Objectives: Hypoxia/reoxygenation (H/R) injury is a critical pathological process during liver transplantation. Kazinol B has known anti-inflammatory, anti-apoptotic, and metabolic regulatory properties, but its protective mechanism in H/R-induced liver injury remains unclear. This study aims to investigate the protective effects and underlying mechanisms of Kazinol B in H/R-induced hepatocyte injury.

Methods: An ischemia-reperfusion model was established in healthy adult male Sprague-Dawley rats, and an in vitro H/R model was created using cultured hepatocytes. Hepatocytes were treated with Kazinol B (0-100 μmol/L) to assess cytotoxicity and protective effects. Cell viability was evaluated using the cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) release assays. Expression of apoptosis-related proteins, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated death promoter (Bad), and cleaved caspase-3, was detected by Western blotting. Reactive oxygen species (ROS) levels were assessed via fluorescence probes, and inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were measured using enzyme-linked immunosorbent assay (ELISA). TdT-mediated nick end labeling (TUNEL) staining was performed to assess DNA damage and apoptosis.

Results: Kazinol B had no significant effect on hepatocyte viability at 0-50 μmol/L, but showed cytotoxicity at 100 μmol/L (P<0.05). At 0.1-20 μmol/L, Kazinol B significantly improved cell survival, reduced LDH release, decreased apoptosis, and attenuated DNA damage (all P<0.001). At 10 μmol/L, Kazinol B markedly down-regulated Bad and cleaved caspase-3 (both P<0.05), and up-regulated Bcl-2 (P<0.01). It also dose-dependently reduced ROS levels and inflammatory cytokines TNF-α and IL-1β (all P<0.01). Both in vitro and in vivo, Kazinol B inhibited activation of the c-Jun N-terminal kinase (JNK) pathway without affecting extracellular regulated protein kinase (ERK) signaling (P>0.05). TUNEL staining showed that the protective effect of Kazinol B against apoptosis was partially reversed by the JNK agonist anisomycin (P<0.01).

Conclusions: Kazinol B mitigates hepatocyte injury induced by H/R by inhibiting the JNK signaling pathway. Its protective effect is associated with suppression of oxidative stress and inflammation, indicating its potential as a hepatoprotective agent.