Evaluating the mitochondrial structure and gene expression profile of regenerated liver tissues in mice after 85% partial hepatectomy

Background: Partial hepatectomy (PH) is the primary method used for treating liver injury and transplantation. The regeneration process after hepatectomy requires an adequate energy supply, and mitochondria serve as the primary source of energy. Alterations in genes related to the respiratory chain complex may impact the liver regeneration process. The aim of this study was the changes in mitochondrial structure and mitochondrial function in 85% PH.

Methods: A PH (up to 85%) model was developed using male C57BL/6 mice, and the regenerated liver tissue was harvested after 24 hours. Hematoxylin and eosin staining and transmission electron microscopy were used for morphological studies. In terms of proliferation, a positive proliferating cell nuclear antigen (PCNA) rate was detected via immunohistochemistry. Real-time polymerase chain reaction was performed to identify differentially expressed genes (DEGs), which were screened using a P value of <0.05 and a |fold change| of ≥1.5. The Hiplot online tool was used for generating a volcano plot and conducting correlation analyses. R software was employed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses for the DEGs. A combined Search Tool for the Retrieval of Interacting Genes/Proteins (STRING)-Cytoscape method was used for protein-protein interaction (PPI) network analyses, whereas cytoHubba was used to the screen core DEGs.

Results: After 85% PH, we observed steatosis, an increased PCNA positivity rate, mitochondrial swelling, and a reduced number of cristae due to cristae disintegration. We screened 30 DEGs that were associated with different processes, including oxidation-reduction, oxidoreductase activity, electron transfer activity, organelle envelope, inner mitochondrial membrane processes, and oxidative phosphorylation as well as those involved in nonalcoholic fatty liver disease (NAFLD). We identified a total of six hub genes: COX4I1, ATP5B, UQCRC2, CYC1, ATP5O, and ATP5A1.

Conclusions: The 85% PH model promotes mitochondrial complex protein expression, thereby providing energy for liver regeneration. The enriched genes were associated with oxidation-reduction, electron transfer activity, and inner mitochondrial membrane processes.