Heme Oxygenase-1 Alleviates Ischemia-Reperfusion Injury by Inhibiting Hepatocyte Pyroptosis after Liver Transplantation in Rats

Objective: Heme oxygenase-1 (HO-1) is a protein involved in the inflammatory response following ischemia-reperfusion injury (IRI). Evidence suggests that pyroptosis plays an important role in IRI. However, the underlying mechanism between HO-1 and pyroptosis in IRI requires further investigation. Methods: Using the "two-cuff" method, a Sprague Dawley rat model of liver transplantation (LT) was established using livers from donors after circulatory death. An automatic biochemical analyzer was used to detect serum alanine transaminase (ALT) and aspartate aminotransferase (AST) levels and evaluate liver function. Paraffin sections of the rat liver were stained with hematoxylin-eosin (HE) to observe the degree of pathological damage. An enzyme-linked immunosorbent assay was used to detect serum levels of interleukin (IL)-1 beta and IL-18. Moreover, western blotting was used to analyze the expression of HO-1, pro-caspase-1, p22, full-gasdermin D (GSDMD), and cleaved-N-GSDMD in the liver. Immunohistochemistry was used to detect NLRP3 expression. Results: HO-1 expression was time-dependent with IRI. HE staining and Suzuki score showed that necrosis was more severe at 6 h after IRI than in controls. Reactive oxygen species (ROS), ALT, and AST levels in the reperfusion were significantly higher at 6 h after IRI. Similar to HO-1 expression, pro-caspase-1, p22, and GSDMD expression in the reperfusion was time-dependent and was significantly higher at 6 h. Compared with the HO-1-shRNA (short hairpin RNA) group, the HO-1 overexpression group significantly inhibited ROS, p22, GSDMD, IL-1 beta, IL-18, ALT, and AST. Immunohistochemistry revealed that NLRP3 levels were the highest in the HO-1 overexpression group. Conclusions: HO-1 improved the survival rate and IRI recovery after LT in rats. This study demonstrates that HO-1 inhibits hepatocyte pyroptosis, thereby reducing IRI after LT.