Effect of Ultrafine Powder of Gastrodiae Rhizoma in Improving Learning and Memory Ability of Vascular Dementia Rats by Regulating Cholinergic System / 中国实验方剂学杂志

ABSTRACT

Objective:To investigate whether ultrafine powder of Gastrodiae Rhizoma （UPG） can alleviate the learning and memory impairment of vascular dementia rats and delay the process of VD， and whether this effect is related to the release of acetylcholine （Ach） through the regulation with acetylcholinesterase （AChE） and choline acetyltransferase （ChAT） and control of cholinergic system. Method:SD rats were randomly divided into sham operation group， UPG low dose group （0.45 g·kg-1）， UPG high dose group （1.8 g·kg-1） and Huperzine A group （80 μg·kg-1）， with 12 rats in each group. The drug administration groups were given orally drugs once a day for 8 weeks， and sham group and model group were given orally the same amount of distilled water. The learning and memory ability of the rats with VD were evaluated by the Morris water maze. Htoxylin eosin（HE） staining was used for pathomorphological observation of hippocampus CA1 area of the rats. The content of Ach was determined by enzyme-linked immunosorbent assay（ELISA）， AChE and ChAT protein expressions were detected by Western blot， and expression of ChAT in hippocampus CA1 area was observed by immunohistochemistry. Result:Compared with the sham operation group， the escape latency of the model group was significantly increased （P<0.01）， and the frequency of crossings platform and the time of staying in the target quadrant were reduced significantly （P<0.01）. HE staining of hippocampal tissues from VD rat showed neuron disorders， loss and degeneration and necrosis， pyknosis of the nucleus and light coloration of the cytoplasm. The level of acetylcholine in the hippocampus was significantly decreased by ELISA （P<0.05）， the expression level of AChE protein was significantly up-regulated， and the expression level of ChAT protein was significantly down-regulated （P<0.01）. Compared with model group， each administration group could significantly reduce the escape latency of the model rats， and significantly increase the frequency of crossing platform and the time of staying in the target quadrant （P<0.01）， the content of Ach was significantly increased （P<0.05）， the expression of AChE protein was significantly down-regulated （P<0.01）， while the expression of ChAT protein was significantly up-regulated （P<0.01）. Conclusion:UPG improves the learning and memory ability of vascular dementia rats， and its mechanism may be related to the increase of Ach， ChAT level and the decrease of AChE level.