Effects of dexmedetomidine on sepsis-induced liver injury in rats

OBJECTIVE: To explore the effect of dexmedetomidine (DEX) on sepsis-induced liver injury in rats and the mechanism of action, providing certain references for the prevention and treatment of sepsis-induced liver injury in clinical practice. MATERIALS AND METHODS: A total of 60 male Sprague Dawley (SD) rats were randomly divided into 3 groups, namely sham operation group (Sham group, n=20), sepsis-induced liver injury group [lipopolysaccharides (LPS) group, n=20], and sepsis-induced liver injury + DEX group (LPS + DEX group, n=20) using a random number table. Rat models of sepsis-induced liver injury were established by intraperitoneal injection of LPS (10 mg/kg), and at the same time, DEX was intragastrically injected at a dose of 50 mu g/kg. After 24 h, the survival analysis curves of each group of rats were plotted. Meanwhile, the levels of liver function indexes and oxidative stress markers were measured at 12 h in each group of rats. Hematoxylin-eosin (H&E) staining assay was carried out to detect the morphological changes of rat liver cells in each group. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling (TUNEL) staining assay was performed to detect the apoptosis level in rat liver tissues in each group. In addition, the expression level of Caspase 3 in three groups of rats was measured through immunohistochemical staining assay. Lastly, the effect of DEX on the protein expression of extracellular signal-regulated kinases 1/2 (ERK1/2) in liver tissues was detected via Western blotting. RESULTS: DEX significantly improved liver dysfunction induced by LPS and raised the 24 h-survival rates of rats (p<0.05). Besides, H&E staining results showed that DEX clearly relieved the pathological damage of rat liver cells caused by LPS. In comparison with LPS group, LPS + DEX group displayed more neatly arranged liver cells, less degradation and necrosis, and evidently attenuated cellular edema. Immunohistochemistry results revealed that DEX significantly reversed the increase in Caspase 3 expression resulting from LPS. The results of the TUNEL staining assay showed that DEX clearly inhibited the apoptosis of rat liver cells induced by LPS. The results of Western blotting revealed that DEX notably reversed the decrease of phosphorylated ERK1/2 (p-ERK1/2) in rat liver tissues compared with LPS group. CONCLUSIONS: DEX is able to markedly relieve LPS-induced liver injury in rats and the underlying mechanism may be related to the activation of the ERK1/2 signaling pathway.