Cognitive enhancement and neuroprotective effects of a traditional Chinese herbal compound medicine on Aβ1–42 induced Alzheimer’s disease in rats

Introduction
We aimed to explore the role of a novel traditional herbal compound medicine (HCM) in Alzheimer’s disease (AD).

Material and methods
72 rats were randomized into control, AD, Donepezil and HCM groups. Injection of -amyloid peptide (A1–42) into the lateral ventricle was used to induce AD in rats. Rats in treatment groups received HCM (1.5, 3.0 and 6.0 g/kg) and Donepezil (0.92 mg/kg) for 21 days, respectively. The spatial learning and memory ability were observed by Morris water maze (MWM) test. Haematoxylin-eosin (HE) staining was carried out for pathological morphology. The contents of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in the hippocampus were determined using the spectrophotometric method. A expression was measured by immunohistochemistry and Western blotting.

Results
Rats in HCM groups spent less time to locate the platform and performed better in spatial learning and memory than the AD group (p < 0.05). Hippocampus in the HCM (6.0 g/kg) group had a complete pyramidal cell layer, in which the structure of morphology was normal and the number of neurons was larger than in the AD group (p < 0.01). The contents of SOD, CAT, GSH-Px were notably increased and MDA content was significantly decreased in the hippocampus in HCM groups than in the AD group (p < 0.01). The expression levels of A1–42 in HCM groups were markedly decreased than in the AD group (p < 0.01).

Conclusions
HCM has a protective effect on the learning and memory capacity in AD in rats, indicating that HCM had cognitive enhancing potentials on AD.