Objective  To explore the role and mechanism of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) in remifentanil (REM) resistance to hepatic ischemia-reperfusion injury (HIRI).

Methods  Forty SD rats were randomly divided into sham surgery group, HIRI group, HIRI+REM group, HIRI+PGC-1α inhibitor SR-18292 (HIRI+SR-18292) group, and HIRI+REM+SR-18292 group, 8 rats in each group. HIRI rat models were constructed using non-invasive arterial clip occlusion method, and REM or SR-18292 were intravenously injected before surgery. The liver function indicators and liver tissue adenosine triphosphate (ATP) levels in the serum of rats were detected by assay kits. The activity levels of mitochondrial respiratory chain complexes Ⅲ and Ⅳ (COX-Ⅲ, COX-Ⅳ) in rat liver tissue were assessed by colorimetric methods. The pathological changes in rat liver tissue were observed by hematoxylin-eosin staining. Reactive oxygen species (ROS) and oxidative stress-related indicators in rat liver tissue were measured using the fluorescent probe (DCFH-DA) method and colorimetric methods. The mitochondrial DNA (mtDNA) copies and the expression levels of PGC-1α, nuclear respiratory factor-1 (NRF-1) and mitochondrial transcription factor A (TFAM) messenger RNA (mRNA) in rat liver tissue were quantified by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR). And the protein expression levels of PGC-1α, NRF-1 and TFAM in rat liver tissue were assessed by Western blotting.

Results  Compared with the sham group, rats in the HIRI group showed increased pathological scores and hepatic cell necrosis in liver tissue, elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum, and increased levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in liver tissue. Additionally, there was a decrease in ATP content and the activity levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), COX-Ⅲ and COX-Ⅳ in liver tissue, as well as a decrease in mtDNA copies and the expression levels of PGC-1α, NRF-1 and TFAM mRNA and protein (all P<0.05). Compared with the HIRI group, rats in the HIRI+REM group exhibited decreased pathological scores and hepatic cell necrosis, reduced levels of serum ALT and AST, and decreased levels of ROS and MDA in liver tissue. There was also an increase in ATP content and the activity levels of SOD, GSH-Px, COX-Ⅲ and COX-Ⅳ in liver tissue, as well as an increase in mtDNA copies and the expression levels of PGC-1α, NRF-1 and TFAM mRNA and protein (all P<0.05). In contrast, rats in the HIRI+SR-18292 group showed increased pathological scores and hepatic cell necrosis, elevated levels of serum ALT and AST, and increased levels of ROS and MDA in liver tissue. There was a decrease in ATP content and the activity levels of SOD, GSH-Px, COX-Ⅲ and COX-Ⅳ in liver tissue, as well as a decrease in mtDNA copies and the expression levels of PGC-1α, NRF-1 and TFAM mRNA and protein (all P<0.05). Compared with the HIRI+REM group, rats in the HIRI+REM+SR-18292 group had increased pathological scores and hepatic cell necrosis, elevated levels of serum ALT and AST, and increased levels of ROS and MDA in liver tissue. There was a decrease in ATP content and the activity levels of SOD, GSH-Px, COX-Ⅲ and COX-Ⅳ in liver tissue, as well as a decrease in mtDNA copies and the expression levels of PGC-1α, NRF-1 and TFAM mRNA and protein (all P<0.05).

Conclusions  PGC-1α plays a role in regulating the process of REM resistance to HIRI by promoting mitochondrial biogenesis and reducing the levels of oxidative stress.