Objective: To study the effect of ozonized saline on the activation of the Keap1-Nrf2-ARE signaling pathway in rat liver cells.
Methods: Twenty male Sprague-Dawley rats were randomly divided into ozonized saline (OS) group, model group, ozonized saline control (OSC) group and normal control (NC) group. The rats in OS group and model group were intravenously administered with OS or oxygen saline (5 ml/kg) respectively, once a day for 15 days, and then intraperitoneally injected with CCl4 dissolved in oliver oil. The rats in OSC group were pretreated with OS for 15 days. The rats in NC group were fed normally for 15 days. On the 16th day, the rats in OSC group and NC group were intraperitoneally injected with oliver oil (2 ml/kg) without CCl4. After 24 hours of CCl4 or olive oil intraperitoneal injection, the serum levels of alanine transaminase (ALT) and aspertate aminotransferase (AST) were measured. The liver tissues were also collected for detection of total anti-oxygen capability (TAOC), glutathione (GSH), catalase (CAT), Glutathione peroxidase (GPx). Western Blot was used to detect Nrf2 and immunofluorescence staining assay to display intracelluar distribution of Nrf2.
Results: Compared with the rats in model group,the serum ALT and AST levels of rats in OS group were significantly lower (P < 0.01) ,which were (1240.4 ± 188.2) U/L and (1245.4 ± 176.9) U/L vs (539.8 ± 175.3) U/L and (546.0 ± 130.2) U/L, and the TAOC, CAT, GPx and GSH activity of rats in OS group were significantly higher, which were (0.72 ± 0.24) U/mg, (1.05 ± 0.21) mg/g, (676.9 ± 115.1) U/mg and (45.2 ± 14.3) U/mg vs (1.37 ± 0.19) U/mg, (2.23 ± 0.55) mg/g, (1024.6 ± 162.9) U/mg and (68.2 ± 9.9) U/mg, respectively. In contrast with NC group, pretreatment of OS in OSC group elevated TAOC, CAT, GPx and GSH activity (P < 0.01 or P < 0.05). Ozonized saline can strengthen the Nrf2 expression in liver cells.
Conclusion: Preconditioning injection of ozonized saline can reduce rat's liver injury induced by CCl4. The ozonized saline, as a novel Nrf2 activator, can reduce the oxidative damage of radical oxygen species (ROS) and the deleterious substance by activating the Keap1-Nrf2-ARE signaling pathway and its downstream genes expression.