Effects of magnolol on impairment of learning and memory abilities induced by scopolamine in mice.

Alzheimer's disease (AD), one of the most common forms of dementia, is primarily ascribed to the cholinergic deficits and neuronal dysfunction. Magnolol (Mag), a bioactivator extracted from Magnolia officinalis, has protective effects on cholinergic neurons, but the specific mechanism remains unknown. To further evaluate the therapeutic effects of Mag on the learning and memory impairment in a scopolamine (Scop)-induced mouse model, the passive avoidance and the Morris water maze tests, the measurement of the ratio of brain/hippocampus to body weight, activities of acetyl cholinesterase (AChE), superoxide dismutase (SOD), total nitric oxide synthase (total NOS) and the content of methane dicarboxylic aldehyde (MDA) in hippocampus homogenate as well as the immunefluorescence staining of the AChE positive nerve fibers were performed. Therapeutically treated with Mag, the impaired abilities of learning and memory of the Scop-induced mice were almost restored to the native levels. The restored AChE, total NOS and SOD activities and the MDA level were observed, with a relatively normal density of AChE positive nerve fibers in hippocampus CA3 molecular layer. The improving efficacy of Mag on learning and memory impairment induced by Scop is dose-dependent, indicating that Mag has potential neuroprotective effects against neuronal impairment and memory dysfunction induced by Scop in mice. The underlying mechanisms may be associated with the anti-oxidative effects of Mag and its protective effects on hippocampus cholinergic neurons.

Correlation of gene polymorphisms of CD36 and ApoE with susceptibility of Alzheimer disease: A case-control study.

This research was aimed to explore correlation of gene polymorphisms of CD36 and ApoE with susceptibility of Alzheimer disease (AD).This study was a case-control study. Two hundred eleven AD hospitalized patients were selected as the AD group and 241 subjects were selected as the control group. PCR-RFLP was used to detect three loci (rs7755, rs3211956, and rs10499859) of CD36 gene and ApoE genotype. Chi-square test and univariate nonconditional logistic regression analysis were used to calculate the odds ratio (OR) and 95% confidence interval (95% CI). The haplotypes were constructed using SHEsis online software and the correlation between haplotypes and AD was analyzed. Meanwhile, differences of 3 alleles of ApoE and 6 genotypes (E2/E2, E2/E3, E2/E4, E3/E3, E3/E4, E4/E4) were compared between AD and control groups.The frequencies of rs7755 genotype (χ = 10.780, P = .005) and allele (χ = 10.549, P = .001) were statistically different between 2 groups. The genotype frequency of rs3211956 was statistically different between AD and control groups (χ = 10.119, P = .006). For the rs7755 locus, GG genotype (OR: 2.013, 95% CI: 1.098-3.699) was an independent risk factor for AD compared with AA genotype. In the dominant model, the risk to develop AD in AG/GG genotype was 1.686 times higher than AA genotype. For the rs3211956 locus, compared with TT genotype, GT genotype (OR: 0.536, 95% CI: 0.340-0.846) was a protective factor for AD after adjusting various physiological and biochemical factors. In the dominant model, the risk of GT/GG genotype to develop AD was reduced by 41.6%. For ApoE gene, the distribution differences of E2/E3 (χ = 9.216, P = .002), E3/E4 (χ = 7.728, P = .005), and E4/E4 had statistical significance between the 2 groups. The frequencies of allele E2 (χ = 9.359, P = .002) and E4 (χ = 13.995, P < .001) were statistically significant between AD and control groups.The rs7755 and rs3211956 loci polymorphisms of CD36 gene and genotype E2/E3, E3/E4, E4/E4 of ApoE gene, and E2 and E4 alleles were statistically related with AD.

Wnt5a Promotes Cortical Neuron Survival by Inhibiting Cell-Cycle Activation.

ß-Amyloid protein (Aß) is thought to cause neuronal loss in Alzheimer's disease (AD). Aß treatment promotes the re-activation of a mitotic cycle and induces rapid apoptotic death of neurons. However, the signaling pathways mediating cell-cycle activation during neuron apoptosis have not been determined. We find that Wnt5a acts as a mediator of cortical neuron survival, and Aß42 promotes cortical neuron apoptosis by downregulating the expression of Wnt5a. Cell-cycle activation is mediated by the reduced inhibitory effect of Wnt5a in Aß42 treated cortical neurons. Furthermore, Wnt5a signals through the non-canonical Wnt/Ca2+ pathway to suppress cyclin D1 expression and negatively regulate neuronal cell-cycle activation in a cell-autonomous manner. Together, aberrant downregulation of Wnt5a signaling is a crucial step during Aß42 induced cortical neuron apoptosis and might contribute to AD-related neurodegeneration.

Baicalein improves behavioral dysfunction induced by Alzheimer's disease in rats.

BACKGROUND: Alzheimer's disease (AD) is considered to be a neurodegenerative disorder that is characterized by increased oxidative stress. Medicinal plants, with their antioxidant properties, have been used to cure several human diseases. The aim of the current study was to explore the protective and therapeutic effect of baicalein on AD-induced rats. MATERIALS AND METHODS: Swiss Wistar rats were used in the study. The rats were divided into five groups. Group I: normal control group treated with water; Group II: disease control treated with AlCl3 to induce the mimicking AD for 4 successive weeks (SW); Group III: normal control group treated with baicalein (5 mg/kg) for 2 SW followed by combination of baicalein and AlCl3 for 4 SW; Group IV: normal control group treated with baicalein (10 mg/kg) for 2 SW followed by combination of baicalein and AlCl3 for 4 SW; Group V: normal control group treated with rivastigmine (0.3 mg/kg) for 2 SW followed by combination of rivastigmine and AlCl3 for 4 SW. Moreover, the therapeutic groups are as follows: Group VI: AD disease control treated with AlCl3 for 4 SW and serving as the therapeutic positive group; Group VII: AD disease control + baicalein (5 mg/kg) for 12 SW; Group VIII: AD disease control + baicalein (10 mg/kg) for 12 SW; Group IX: AD disease control + rivastigmine (0.3 mg/kg) for 12 SW. Behavioral test, T-maze, and rotarod test were also performed before and after the treatment. At the end of the experimental study, all the rats were sacrificed and their brains were removed and divided into two portions. The first portion was homogenated for estimating the level of acetylcholinesterase (AchE) and acetylcholine (Ach). Another portion was used for histopathological evaluation. RESULTS: The current investigation showed that baicalein significantly reduced the duration of revolving on the rotarod, cage activity, and T-maze activity in a dose-dependent manner compared with the AD control group rats. It also altered the AchE and Ach levels in the brain homogenates. The histopathology study also provides strength to the protective effect of baicalein. CONCLUSION: The current study showed that baicalein significantly (P<0.05) improved the biochemical and histopathological condition of AD in rats.