Transcriptome was utilized to unravel the liver tissue changes of the successful recovery from freezing in the...

The Amur sleeper (Perccottus glenii) exhibits remarkable tolerance to freezing conditions, yet the molecular and physiological mechanisms underlying its recovery from cold stress remain poorly understood. This study investigated the recovery process in P. glenii following freezing by integrating transcriptomic, histological, and biochemical analyses. Fish were subjected to a freezing experiment at -2 °C for 24 h, followed by a recovery phase at 4 °C. Liver transcriptome sequencing revealed 5622 differentially expressed genes (DEGs) across comparison groups (DEA vs. CK, SUR vs. CK, and DEA vs. SUR). KEGG enrichment analysis highlighted the significant upregulation of genes involved in the pancreatic secretion pathway and in the metabolism of xenobiotics by cytochrome P450 and steroid biosynthesis pathways in successfully resuscitated individuals. Histological examination showed restored liver architecture in the successful recovery group, contrasting with vacuolation and structural disorganization in the death group. Biochemically, successful recovery was associated with significantly elevated activities of antioxidant enzymes and digestive enzymes (lipase), alongside increased triglyceride (TG) content. These findings demonstrate that the successful post-freezing recovery in P. glenii is underpinned by the coordinated upregulation of genes facilitating the restoration of digestive function, enhancement of detoxification capacity, regulation of steroid biosynthesis, and mitigation of oxidative stress. This study provides comprehensive insights into the adaptive molecular mechanisms that confer exceptional freezing tolerance and recovery capability in this vertebrate model.