Effect of Daicong solution on hippocampal muscarinic receptors 1 and 3 gene expression in a rat model of Alzheimer’s disease

摘要

BACKGROUND: It has been previously shown that the muscarinic (M) receptor is involved in brain arousal and selective attention, mood, and motor coordination. OBJECTIVE: To explore the effects of various intragastric Daicong doses on hippocampal M1 and M3 receptor gene expression in a rat model of Alzheimer’s disease. DESIGN, TIME AND SETTING: A randomized cellular and molecular biology experiment, conducted at the Molecular Immunology Laboratory in Shandong between October 2006 and April 2007. MATERIALS: Fifty 22-month old Sprague Dawley rats, weighing 250-300 g were used for this experiment. Kainic acid was used to lesion the nucleus basalis to establish a rat model of Alzheimer’s disease. The components of Daicong solution were as follows: ginseng, rehmannia dride rhizome, anemarrhena, and radix astragali. The solution was provided by the Affiliated Hospital to Weifang Medical College, according to preparation techniques of extracting liquid for traditional Chinese medicine (1 g crude drug/mL solution). Kainic acid was provided by Professor Xiuyan Li at Weifang Medical College. METHODS: The rats were randomly divided into 5 groups, 10 rats in each group. Four groups were used for model establishment, and the fifth group served as a normal control group. Three of the model groups were intragastrically administered 5, 10, and 20 g/kg/d Daicong solution, and an additional model group and normal control group received normal saline (10 mL/kg/d). Drugs were administered over a time period of one month. MAIN OUTCOME MEASURES: Four days after model establishment, Morris water maze was used to measure learning and memory capabilities. RT-PCR was used to detect the effect of Daicong solution on mRNA expression of M1 and M3 receptor in the hippocampus of all groups. RESULTS: Fifty rats were included in the final analysis, without any loss. M1 and M3 receptor mRNA expression was decreased in the model group, compared to the normal control group (P < 0.05). Upon Daicong administration (10 g/kg/d and 20 g/kg/d), M1 and M3 receptor mRNA expression significantly increased in the hippocampus, compared to the model group (P < 0.05). M1 and M3 mRNA expression was greatest in the 10 g/kg/d group. CONCLUSION: A 10 g/kg/d solution of Daicong can improve M1 and M3 receptor mRNA expression in the hippocampus of a rat model of Alzheimer’s disease.