Background: Inflammation plays a crucial role in kidney damage after crush syndrome (CS). Several researchers report that high mobility group box-1 protein (HMGB1) may be the vital trigger in kidney damage, and tumor necrosis factor-α (TNF-α) and c-Jun N-terminal kinase (JNK) are involve in this pathophysiological process, but their biological roles are unclear. This study aimed to explore the relationship between HMGB1, JNK, and TNF-α in kidney damage.
Methods: The crush injury model was established using weight compression. The reliability of the crush injury model was determined by hematoxylin-eosin (HE) staining. Western blot was used to detect the expression of HMGB1, JNK, and TNF-α, and TUNEL was used to mark apoptotic cells in the renal cortex.
Results: The results showed that the highest expression of HMGB1 in muscle was 12 h after CS. JNK and TNF-α increased and peaked at 1 day after CS in kidneys. Western blot analysis revealed that anti-HMGB1 antibody could downregulate the expression of JNK and TNF-α. Anti-TNF-α could downregulate activation of JNK, and SP600125 could downregulate expression of TNF-α in the kidneys. In addition, anti-HMGB1 antibody, anti-TNF-α antibody, and SP600125 could reduce cellular apoptosis in the renal cortex.
Conclusions: It is possible that JNK and TNF-α commonly contribute to kidney damage by assembling a positive feedback cycle after CS, leading to increased apoptosis in the renal cortex. HMGB1 from the muscle may be the trigger.
Keywords: Apoptosis; Crush injury; High mobility group box-1; SP600125; Tumor necrosis factor-α (TNF-α); c-Jun N-terminal kinase (JNK).