Effects of Tianqi-Yizhi granules on oxidative stress in the brain tissue, and learning and memory in Alzheimer's disease model rats

Abstract

Objective To investigate the effects of Tianqi-Yizhi granules on oxidative stress in the brain tissue, and learning and memory in Alzheimer's disease model rats. Methods A total of 90 male SD rats were randomly divided into 6 groups by random number table method: sham operation group, model group, huperzine A group and groups of low-, medium- and high-dose Tianqi-Yizhi granules, with 15 rats in each group. The AD rat model was prepared by the left lateral ventricle injection of amyloid-β1-42. One week after modeling, the rats in the groups of low-, medium- and high-dose Tianqi-Yizhi granules received intragastric administration of 0.8, 1.6 and 3.2 g/kg Tianqi-Yizhi granules, respectively; the rats in the huperzine A group received intragastric administration of 0.02 mg/kg huperzine A solution; and the rats in the sham operation and model groups received intragastric administration of equivalent volume of normal saline for 30 days. Learning and memory were evaluated using the dark avoidance test. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and malonaldehyde (MDA) level in the brain tissue were determined. Results In comparison with the model group, the latencies to step into the dark chamber in the high- and medium-dose Tianqi-Yizhi granules groups were significantly longer (239.05 ± 48.42 s, 214.35 ± 74.52 s vs. 97.39 ± 30.69 s; all P<0.01), the numbers of errors significantly decreased (1.93 ± 3.25, 2.27 ± 3.09 vs. 6.62 ± 3.45; all P<0.05), the activities of SOD (177.27 ± 63.10 U/mg, 164.53 ± 72.58 U/mg vs. 72.56±21.04 U/mg; all P<0.01) and GSH-Px (2 899.36 ± 362.27 U/g, 2 407.68 ± 472.14 U/g vs. 1 397.64 ± 442.17 U/g; all P<0.01), and MDA level (24.75 ± 9.94 nmol/mg, 27.74 ± 5.82 nmol/mg vs. 37.56 ± 17.23 nmol/mg; all P<0.01) in the brain tissue significantly increased. Conclusion Tianqi-Yizhi granules could attenuate oxidative stress in the brain tissue, and improve learning and memory in AD rats. Key words: Alzheimer disease; Learning; Memory; Oxidative stress; Rats; Tianqi-Yizhi granules