Studies On The Effects And Mechanisms Of CE On Dementia Rats Induced By Ibotenic Acid (IBO)

Alzheimer's disease (AD) is a degenerative neuropathy characterized by mental retardation. The neuron loss in the cortex and hippocampus is one of its pathological features. With the ageing of the society, the prevalence of AD increases. But its etiology is not clear. Degeneration of cholinergic neuron is main factor resulting in deficit of learning and memory ability in AD patients with obvious lesion of nucleus basalis of Meynert (nbM) projecting to the extensive district of cerebral cortex and hippocampus.In the research of Chinese Traditional Medicine to treat AD, we have found that CE-wangla [Coeloglossum. viride (L.) Hartm. var. bracteatum (Willd. ) Richter] extract could ameliorate the impairment of learning and memory on several dementia animal models. In this research, Ibotenic acid (IBO) was stereoscopic injected into bilateral nbM of SD rats to induce lesion of nbM. Effects of CE on the learning and memory function of IBO-treated rats were investigated using step-through test and step-down test. Furthermore, effects of CE on the changes in aspects of rat body weights, neuron morphology, enzyme activities and expressions in rat brain were investigated to clarify the mechanisms of CE's action.Male adult SD rats were divided randomly into 6 groups, including sham group, model group, positive control agent piracetam group, CE low (0.31mg/kg), medium (1.25mg/kg) and high (5mg/kg) dosage group. About 1 hour before operation, water or drugs were fed orally to each group respectively. By the 22th day, step-through test and step-down test were performed. Latency (time of rats from light room to dark room) in step-through test or first step-down time in step-down test were recorded.The rat step-through latency did not show significant difference between all groups in learning trail, indicating that all rats had similar behavior to dark. But 24 hours after the training trail, the performance of model group rats was worse than that of sham group rats in retention test, which indicated that IBO treatment produced learning and memory impairment in rats. CE markedly improved the function of leaming and memory in IBO-treated rats in...