Effects Of Tianqi Yizhi Granule On Learning And Memory And Central Neurotransmitters In Senescence Accelerated Mice

Objectives:To investigate Tianqi Yizhi granule’s influence on the degenerate cognitive ability of patient with Alzheimer’s disease and its impact on concentration of monoamine neurotransmitter within brain tissues such as Norepinephrine (NE) and serotonin (5-HT), meanwhile, to explain the mechanism of Tianqi Yizhi granule’s role in improving the learning and cognitive ability of mice with Alzheimer’s disease and provide the essential laboratory evidence for developing original method of preventing or combating Alzheimer’s disease or other aging related disease, senescence-accelerated prone mice (SAMP8) were adopted as the animal model.Methods:1.50 SAMP8 mice were firstly numbered by their body weight, then according to a random number table, the mice were randomly divided into 5 different groups, each containing 10 mice, including the imitated Alzheimer’s disease group (AD), the huperzine A group, the Tianqi Yizhi granule high-dosage group, the Tianqi Yizhi granule medium-dosage group and the Tianqi Yizhi granule low-dosage group. And a control group was set up with 10 senescence accelerated mouse-resistance/1 (SAMR1) mice. After 5 days adaptive breeding, different kinds and dosage of medicine were intragastric administered respectively for 60 days:huperzine A group (0.07mg/kg·d-1), Tianqi Yizhi granule high-dosage group (0.88g/kg·d-1), Tianqi Yizhi granule medium-dosage group (0.58g/kg·d-1), Tianqi Yizhi granule low-dosage group (0.31g/kg·d-1), SAMR1 control group and SAMP8 model group (isometric normal saline).Nesting experiment, dark avoidance test and Morris water maze experiment was used to evaluate the learning and cognitive ability of mice, contents of serotonin (5-HT) and norepinephrine (NE) in brain were measured by HPLC -ECD.2. Statistic Method:SPSS v.17.0 statistic software was used to analyze the results of the experiment, all test data were statistically described as x±s. The results of Morris water maze hidden platform test were analyzed by Two-Way ANOVA with repeated measures and the other comparisons among groups’ mean measurements were all tested by One-Way ANOVA analysis.Results:Compared with SAMR1 group, the score of nesting experiment of mice from SAMP8 group had significantly decreased (P<0.05); the latent period of dark avoidance test was obviously lowered (P<0.01), the error counts of dark avoidance test was significantly increased (P<0.05), the latent period of Morris water maze hidden platform test had significantly prolonged on the third and forth day (P<0.01), while moderately prolonged on the fifth day (P<0.05), the number of successfully crossing the targeted platform in space exploration experiment had significantly decreased (P<0.01). As compared with the model group, the nesting experiment score of mice from Tianqi Yizhi granule medium-dosage group had significantly increased (P<0.05); according to the mice from Tianqi Yizhi granule high-dosage group, the latent period of dark avoidance test had significantly prolonged (P<0.01), while error counts of dark avoidance had significantly lowered (P<0.05); the latent period of Morris water maze hidden platform test had significantly shortened on the fourth day(P<0.05), according to Tianqi Yizhi granule medium-dosage group, the latent period of dark avoidance test had significantly prolonged (P<0.05) and the latent period of Morris water maze hidden platform test had significantly shortened on the third and fourth day (P<0.05), the number of successfully crossing the targeted platform in space exploration experiment of mice from Tianqi Yizhi granule high-dosage group and Tianqi Yizhi granule medium-dosage group both had significantly increased (P<0.01 or P<0.05), the contens of NE and 5-HT in brain tissue had significantly increased in Tianqi Yizhi granule middle and high dosage group(P<0.05).Conclusions:1. Tianqi Yizhi granule has a relatively strong effect of improving the learning and cognitive ability of SAMP mice.2. The mechanism of Tianqi Yizhi granule’s influence on SAMP mice’s learning and cognitive ability may be associated with its role in regulating NE and 5-HT located in brain tissue.3. Tianqi Yizhi granule have a potential of anti-senile-dementia or other age-related disease and it could provide some value for further exploitation.