Effects Of Dendrobium Nobile Lindl. Alkaloids On Different-months APP/PS1 Mice’s Learning And Memory Ability

Objective:The current study was designed to investigate the effects of DNLA on the learning and memory of different-months transgenic mice.Methods: The time detecting the learning and memory of male APP/PS1 transgenic mice was set as 5-month-age, 7-month-age, 9-month-age, 13-month-age and 16-month-age. The same-month-age wild type mice were regarded as control group at every detection time.(1) When the mice were kept and observed to 5-month-age, we tested the learning and memory ability of both 10 male APP/PS1 transgenic and same-month-age wild type mice using Morris water maze, and compared the differences between two groups in learning and memory ability.(2) 40 male APP/PS1 transgenic mice were randomly divided into model, DNLA-L( 40 mg/kg), DNLA-H( 80 mg/kg) and metformin( 80 mg/kg) groups, and 10 same-month-age wild type mice were regarded as control group. When the mice were kept and observed to 6-month-age, we started to perform administrations and last for 4 weeks until the mice were in 7-month-age. 1 week before finishing the administrations, we tested the learning and memory ability of the mice using Morris water maze.(3) 40 male APP/PS1 transgenic mice were randomly divided into model, DNLA-L( 40 mg/kg), DNLA-H( 80 mg/kg) and metformin( 80 mg/kg) groups, and 10 same-month-age wild type mice were regarded as control group. When the mice were kept and observed to 7-month-age, we started to perform administrations and last for 8 weeks until the mice were in 9-month-age. 1 week before finishing the administrations, we tested the learning and memory ability of the mice using Morris water maze.(4) 40 male APP/PS1 transgenic mice were randomly divided into model, DNLA-L( 40 mg/kg), DNLA-H( 80 mg/kg) and metformin( 80 mg/kg) groups, and 10 same-month-age wild type mice were regarded as control group. When the mice were kept and observed to 9-month-age, we started to perform administrations and last for 16 weeks until the mice were in 13-month-age. 1 week before finishing the administrations, we tested the learning and memory ability of the mice using Morris water maze.(5) 30 male APP/PS1 transgenic mice were randomly divided into model, DNLA( 40 mg/kg) and metformin( 80 mg/kg) groups and 20 same-month-age wild type mice were randomly divided into control and wild type DNLA( 40 mg/kg) groups. When the mice were kept and observed to 13-month-age, we started to perform administrations and last for 12 weeks until the mice were in 16-month-age. 1 week before finishing the administrations, we tested the learning and memory ability of the mice using Morris water maze.Results:(1) At 5-month-age detection time, place navigation tests of Morris water maze showed that there was no difference between model group and control group on escape latency. The probe trial assay data showed that there was no difference between model group and control group on the time and the percentage of distance in the target quadrant and the number of crossing hidden platform.(2) At 7-month-age detection time, place navigation tests of Morris water maze showed that compared with control group, the escape latency in model group expanded.The probe trial assay data demonstrated that compared with control group, the time and the percentage of distance in the target quadrant both decreased in model group and the number of crossing hidden platform decreased in model group.(3) At 9-month-age detection time, place navigation tests of Morris water maze showed that compared with control group, the escape latency in model group expanded. The probe trial assay data demonstrated that compared with control group, the time and the percentage of distance in the target quadrant both decreased in model group and the number of crossing hidden platform decreased in model group. Compared with model group, DNLA-L shorted the escape latencyand increased both of the time and the percentage of distance in the target quadrant.(4) At 13-month-age detection time, place navigation tests of Morris water maze showed that compared with control group, the escape latency in model group expanded. The probe trial assay data demonstrated that compared with control group, the time and the percentage of distance in the target quadrant both decreased and the number of crossing hidden platform decreased in model group. Compared with model group, DNLA-L shorted the escape latencyand increased both of the time and the percentage of distance in the target quadrant and increased the number of crossing hidden platform. DNLA-H shorted the escape latency and increased both of the time and the percentage of distance in the target quadrant and increased the number of crossing hidden platform. Metformin shorted the escape latency and increased both of the time and the percentage of distance in the target quadrant.(5) At 16-month-age detection time, place navigation tests of Morris water maze showed that compared with control group, the escape latency in wild type DNLA group shorted. The probe trial assay data demonstrated that compared with control group, the number of crossing hidden platform increased in wild type DNLA group.Conclusion:(1) The time that APP/PS1 transgenic mice show theimpaired learning and memory ability is before 7-month-age.(2) Treating with DNLA can improve thelearning and memory ability of the middle-age APP/PS1 transgenic mice.(3) DNLA can improve the old-age normal mice’s learning and memory ability, but can’t improve the old-age APP/PS1 transgenic mice’s.(4) Metformin can improve the middle-age APP/PS1 transgenic mice’s learning and memory ability, but can’t improve the old-age APP/PS1 transgenic mice’s.