Effects of puerarin on learning and memory of model mouse with beta amyloid peptide-induced dementia / 中国组织工程研究

ABSTRACT

BACKGROUND: Puerarin, the main effective component of Chinese herb, Radix puerariae, is isoflavone monomer, which can counteract learning and memory impairment induced by scopolamine or D-galactose etc.OBJECTIVE: To investigate the protective effects of puerarin on β-amYloid peptide-induced learning and memory impairment of model mouse of dementia and the changes of superoxide dismutase activity and malondialdhehyde content in brain and blood.DESIGN: Randomized controlled trailSETTING: Department of Pharmacology, Capital University of MedicalSciencesMATERIALS The experiment was conducted in Departmentof Pharmacology of Capital University of Medical Sciences from March to June 2002.A total of 40 ICR mice were selected and randomly divided into 4 groupspseudooperation group, dementia model group, puerarin 25 mg/kg group and puerarin 50 mg/kg group, with 10 in each group.METHODS: ①Model preparation After anaesthesia with pentobarbital sodium, single intraventricular injection of 3 μL β-amyloid peptide was conducted from right side on each mouse in dementia model group, puerarin 25 mg/kg group and puerarin 50 mg/kg group under aseptic manipulation. The same operation was carried out on the mouse in pseudooperation group but without injection of β-amyloid peptide. ②Giving medicine10 mL/kg physiological saline was intraperitoneally injected into the mouse in pseudooperation group and model group; 25 mL/kg puerarin was intraperitoneally injected to the mouse in 25 mg/kg puerarin group; 50 mL/kg puerarin was intraperitoneally injected to the mouse in 50 mg/kg puerarin group.The medicines were given to each group from the day of model preparation on and behavioral test was carried out 12 days later. ③ Morris water maze examination was used to detect learning and memory ability of the mice.Time for finding the platform (escape latency) in 2 minutes, swimming distance, original angle and search strategy were recorded as learning results.④When the above experiment was finished, anaesthesia with ether was applied to the mice and blood was collected from the orbit to prepare serum.After that, the mice were put to death by decapitation and the tissue of right-brain of the mice were rapidly took out to prepare cerebral homogenate in ice bath, then superoxide dismutase activity and malondialdhehyde content were determined in brain and serum.MAIN OUTCOME MEASURES: ①Escape latency, swimming distance,search strategy and original angle for the mouse in each group to reach the latform. ②Superoxide dismutase activity and malondialdhehyde content in brain and blood of the mouse in each group.RESULTS: All the 40 mice were involved in result analysis. ① Escape latency and swimming distance were shortened in puerarin 25 mg/kg and 50 mg/kg groups (P ＜ 0.05-0.01). The results of search strategy and original angle indicated that as the number of training days increased, the frequency of randomization+magin strategy gradually decreased; The decreasing rates and extents in pseudooperation group and puerarin 25 mg/kg and 50 mg/kg puerarin were more rapid than that in dementia model group,meanwhile, the increasing rates and extents of frequency of tendency+directness strategy in these groups were more rapid than that in dementia model group. There was no significant difference in original angle between groups (P ＞ 0.05). ② The content of superoxide dismutase increased and that of malondialdhehyde decreased in brain and blood of the model mouse in puerarin 25 mg/kg group andpuerarin 50mg/kg group (P ＜ 0.05 -0.01).CONCLUSION: Puerarin can counteract the neurotoxicity of β-amyloid peptide, which improves learning and memory of model mouse. It is not relevant to the dosage but probably related with elimination of cerebral free radical and improvement of antioxidation activity.