Effect Of Tianqi Yizhi Decoction On Synaptic Function In Rats With Alzheimer 's Disease

Alzheimer’s disease is one of the neurodegenerative diseases and it is pathologically characterized by senile plaque, neurofibrillary tangles, blood vessel amyloidosis and neuron loss, whose manifestations are progressive cognitive impairment and behavior damages. With the growth and aging of the population, the incidence of Alzheimer’s disease shows a rapid increase. Alzheimer’s disease has become a public health priority, and it has a huge economic impact. As one of the early pathological changes, the synaptic failure in Alzheimer’s disease gains its own position. The damage of synapses is closely related to the cognitive impairment. Therefore the treatment focusing on how to reverse or slow down these changes is one of the hotpots in resent years. Tianqiyizhi Formula may improve the cognitive impairment of Alzheimer’s disease rats by interact with the synapse function.Objective:To investigate the effect of Tianqiyizhi Formula on learning and memory ability of Alzheimer’s disease rats; to test the activity of ChAT and AchE in Alzheimer’s disease rats’brain cortex; to observe the impact of Tianqiyizhi Formula on the expression of synaptophysin, MAP-2.Methods:We built the Alzheimer’s disease animal models by injecting of Aβ1-42 into lateral ventricle, and the animals were randomly divided into 6 groups of 15 rats each, model group, sham operation group, medicine group (huperzine), low-dose Tianqiyizhi Formula group, medium-dose Tianqiyizhi Formula group, high-dose Tianqiyizhi Formula group. After continuously administered for 30 days, water maze test and step through test were used to evaluate the learning and memory skills. Meanwhile, we measured the activity of ChAT and AchE with spectrophotometry method. Meanwhile, we test the expression of synaptophysin MAP-2 and in rats’brain by using western blot technology.Results:(1) Morris water maze:the latency of the model group was longer than the sham operation group, and the time of staying in the objective quadrant and the time of crossing the objective quadrant decreased (P<0.01).In the Tianqiyizhi Formula groups, the latency were shorter, and the time of staying in the objective quadrant and the time of crossing the objective quadrant increased(P<0.01, P<0.05). Step through test:in the model set, the latency was shorter and times of errors were increased. The latency was significantly increased in the Tianqiyizhi Formula groups (P<0.01). In the treatment groups,the error times decreased (P<0.01). (2) After the injection of the A01-42, the activity of AChE was higher than the sham operation set while the activity of ChAT was much lower (P<0.01), Tianqiyizhi Formula had altered the activity change of AChE (P<0.01, P<0.05), but it had no effect on ChAT (P>0.05). (3) In the model set, the expression of synaptophysin and MAP-2 were both down-regulated (P<0.01), and they were both up-regulated in the Tianqiyizhi Formula sets (P<0.01).Conclusions:Tianqiyizhi Formula had improved the ability of learning and memory of Alzheimer’s disease rats and it down-regulated the activity of AchE in rats’brain, but it had no impact on ChAT. Meanwhile, Tianqiyizhi Formula had a positive influence on the synapse function by up-regulating the expressions of synaptophysin and MAP-2.