Hypoxia induced cognitive impairment modulating activity of Cyperus rotundus

Abstract

Hypobaric hypoxia leads to decrease in cellular oxygen content which subsequently damages the hippocampus with an increase in brain oxidative stress and impairs the memory of the individual. In the present study, we have evaluated the cognitive impairment modulating activity of total oligomeric flavonoids fraction of Cyperus rotundus (TOF) in Sprague Dawley rats. The rats were trained for memory activity for a period of 7days followed by 7days exposure to 25,000ft. altitude and the spatial reference memory was evaluated. Behavioral analysis of the rats by Morris water maze experiment showed that TOF supplementation enhanced the spatial reference memory activity of the rats exposed to hypobaric hypoxia. The decrease in antioxidant status of the animals exposed to hypoxia was restored with TOF supplementation. The increase in ROS, lipid peroxidation products and protein carbonyls of the hippocampus was significantly decreased in animals with TOF administration. The histological assessment of the pyramidal cells of the hippocampus of hypoxia-exposed animals showed nuclear damage and TOF supplementation prevented nuclear damage. TOF administration suppressed hypoxia-induced increase in serotonin, dopamine, and norepinephrine. GABA and Ach levels were decreased by hypoxia which was prevented by TOF supplementation. The increase in GFAP, HIF-1α and VEGF expression in CA3 region of the hippocampus in hypoxia-exposed rats was decreased in TOF administered rats. Taken together, TOF extract ameliorates hypobaric hypoxia induced memory impairment and neurodegeneration in hippocampus through its anti-stress effects.