Oxidative stress on ischemia/reperfusion injury in mice with non-alcoholic hepatic steatosis or steatohepatitis

Hypothermic oxygenated perfusion ameliorates ischemia-reperfusion injury of fatty liver in mice via Brg1/Nrf2/HO-1 axis

BACKGROUND

After cold storage (CS) and subsequent transplantation, fatty liver is more inclined to develop liver dysfunction and serious postoperative complications in contrast to healthy liver. Hypothermic oxygenated perfusion (HOPE) is a safe and efficacious system, which can repair fatty liver and reduce ischemia-reperfusion injury. The aim of this research is to investigate the function of Brg1/Nrf2/HO-1 signaling pathway in the protective effect of HOPE on ischemia-reperfusion injury of fatty liver.

METHODS

The mouse fatty liver model was successfully established and verified by hematoxylin-eosin (HE) staining and oil red O staining. The animals were divided into Control group, CS group and HOPE group. The levels of liver enzyme and lactate in the perfusate were used to measure liver function and cellular metabolism. HE staining and TUNEL staining were utilized to assess the tissue structure and apoptosis, respectively. The levels of superoxide dismutase, malondialdehyde and reactive oxygen species in liver tissue were measured to quantitatively analyze the degree of oxidative stress, and the expressions of protein Brg1, Nrf2 and HO-1 were detected by means of the western blot. Double-labeling immunofluorescence was to explore the colocalization of Brg1 and Nrf2.

RESULTS

The injury of the liver in the CS group was more serious than that in the control group. However, HOPE could significantly reduce the injury, which was manifested by the improvement of liver function and cellular metabolism, and the lower degrees of apoptosis, necrosis and oxidative stress. Furthermore, the expressions of Brg1, Nrf2 and HO-1 in the HOPE group were significantly increased than those in the CS group.

CONCLUSIONS

One-hour HOPE treatment before reperfusion can obviously improve the injury of fatty liver in mice. The underlying mechanism may be that the interaction of Brg1 and Nrf2 can selectively activate the transcription of HO-1.

Purine Metabolism in Platelets and Heart Cells of Hyperlipidemic Rats

PURPOSE

Hyperlipidemia, characterized by an increase in circulating lipid levels, doubles the chance of developing cardiovascular diseases. It prompts inflammation, immune activation, and oxidative stress in the bloodstream and organs of rats. Thus, we theorized that the metabolism of purines, an immunomodulatory mechanism, is altered in cells involved in the development of cardiovascular diseases.

METHODS

Therefore, we induced acute hyperlipidemia in Wistar rats with Poloxamer-407 and euthanized the animals 36 h later. The leucocyte differential, the rate of purine metabolism on the surface of platelets and heart cells, and markers of oxidative stress in the heart tissue were evaluated. These parameters were also assessed in animals pretreated for 30 days with curcumin and/or rutin.

RESULTS

Hyperlipidemia increased the hydrolyses of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) in platelets. In heart cells, the metabolism of ATP and adenosine (ADO) were increased, while ADP hydrolysis was reduced. Additionally, lipid damage and antioxidant defenses were increased in heart homogenates. Hyperlipidemic rats also exhibited a reduced percentage of eosinophils and lymphocytes.

CONCLUSION

Together, these findings are indicative of an increased risk of developing cardiovascular diseases in hyperlipidemic rats. The pretreatments with antioxidants reverted some of the changes prompted by hyperlipidemia preventing detrimental changes in the cells and tissues. Graphical Abstract.