Protective effect of 5,6,7,8-trtrahydroxyflavone against acute hypobaric hypoxia induced-oxidative stress in mice.

Severe oxidative stress triggered by acute hypobaric hypoxia (AHH) is harmful for lots of organs in body, especial brain and heart. Flavonoids with antioxidant properties can protect organs from oxidative stress. Our previous study found that 5,6,7,8-trtrahydroxyflavone (5,6,7,8-THF), a flavones with four consecutive hydrogen group on ring A, showed excellent antioxidant properties in vitro. In the present study, the protective of 5,6,7,8-THF against oxidative stress caused by AHH was investigated. Mice were administered with 5,6,7,8-THF(500mg/kg) for 5 consecutive days before HH exposure. The heart rate (HR) and blood pressure (BP) was measured. The activity of SOD, CAT, GSH-Px, LDH, Na+-K+-ATPase and Ca2+-Mg2+-ATPase and the content of H2O2, MDA, LD and ATP in brain and heart tissue was evaluated using commercial kit. AHH led to a significant increase in HR and decrease in BP. Pretreatment of 5,6,7,8-THF could reversed these changes. In addition, administration of 5,6,7,8-THF could significantly increase the activity of SOD, CAT and GSH-Px and decrease the content of H2O2 and MDA in the brain and heart of mice under AHH. Furthermore, 5,6,7,8-THF inhibited the activity of LDH, decreased the level of LD and improved ATPase activity. These results indicate that 5,6,7,8-THF may protect the mice against AHH injury via scavenging free radical, inhibiting lipid peroxidation, enhancing antioxidant enzyme activity, preserving energy metabolism and can be further explored as an excellent anti-hypoxia agent for preventing acute mountain sickness.