[Verification of a sporadic Alzheimer disease model in SORL1 gene knockout mice].

OBJECTIVE: To compare the behavioral and pathological features of SORL1 gene knockout mice with those of normal mice and APP/PSE1 mice to verify the feasibility of using SORL1 knockout mice as a model of sporadic Alzheimer disease. METHODS: SORL1 gene of fertilized mouse eggs were edited using Crispr/Case9 technique. SORL1-/- mice were screened and identified by detecting the DNA sequence, and Western blotting was used to detect the expression of SORL1. SORL1-/- mice, control mice and APP/PSE1 mice all underwent Morris water maze test to assess their learning and memory abilities with positioning navigation and space exploration experiments. The expression of APP and Aß in the brain of the mice was detected using immunohistochemistry and Western blotting, respectively. RESULTS: DNA sequencing showed CAAT deletion in SORL1 gene in two chromosomes of SORL1-/- mice, and the control mice had intact SORL1 gene without the deletion; Western blotting did not detect the expression of the SORL1 in the brain of SORL1-/- mice. Morris water maze test showed that in positioning navigation experiment, the average avoidance latency was similar between SORL1-/- mice and APP/PSE1 mice (P>0.05) but increased significantly in both mice as compared with the control group (P<0.05); similar results were obtained in the space exploration experiment. Immunohistochemistry and Western blotting revealed significantly increased APP and Aß expression in the brain tissue of both SORL1-/- mice and APP/PSE1 mice compared with the control mice without significant differences between the two transgenic mice. CONCLUSION: SORL1-/- mice exhibit similar behavioral and pathological changes with APP/PSE1 mice and can be used as a model of sporadic Alzheimer's disease.

[Protective effect of butylphthalide in a cell model of Alzheimer's disease induced by Aß25-35 in Neuro 2a cells].

OBJECTIVE: To study the protective effect of butylphthalide in a cell model of Alzheimer's disease(AD) induced by Aß25-35 in Neuro 2a (N2a) cells. METHODS: N2a cells were divided into AD group, butylphthalide (NBP) group and control group. AD cell model was established by adding 20 µmol/L Aß25-35 to cultured N2a cells. The cells in NBP group were treated with 0.1, 1, 10, or 100 µmol/L NBP 4 h prior to treatment with 20 µmol/L Aß25-35. The cell viability were determined by MTT assay, the cell apoptotic rate were detected by AnnexinV-FITC flow cytometry, and the cell morphological changes were observed under inverted phase contrast microscope. The expression of TNF-α and IL-1ß mRNA were determined by qRT-PCR. RESULTS: Compared with those in the control group, the number of adherent cells was significantly decreased, neurite structures were reduced, and the cell viability was decreased, while the apoptotic rate and expressions of TNF-α and IL-1ß mRNA were increased in AD group (P<0.05). Compared with that in AD group, the number of adherent cells was increased in NBP group and the cell morphology was similar to the normal control cells. The cell viability of N2a cells was increased in NBP group with decreased apoptotic rate and expression of TNF-αand IL-1ß mRNA (P<0.05). CONCLUSION: Butylphthalide can protect against AD in the cell model induced by Aß25-35 possibly by inhibiting the expression of inflammatory cytokines.

Mutant presenilin2 promotes apoptosis through the p53/miR-34a axis in neuronal cells.

Neurodegenerative disorders have attracted attention in last decades due to their high incidence in the world. The p53/miR-34a axis triggers apoptosis and suppresses viability in multiple types of cells, but little is known about its role in neurodegenerative diseases. In this study, we showed that presenilin (PS)-2, a major gene associated with familial Alzheimer's disease (AD) could trigger the apoptosis through the p53/miR-34a axis in PC12 cells. First we found that PC12 cell viability was downregulated by PS-2 and mutant PS-2 overexpression, especially by mutant PS-2 overexpression. Then, we established a mutant PS-2-overexpressing PC12 cell line and confirmed that mutant PS-2 induced not only p53 but also miR-34a expression. The transfection of miR-34a inhibitor reversed PS-2-induced effects on cellular viability and apoptosis. Mutant PS-2 overexpression promoted caspase-3 expression, reduced Sirt1 and Bcl-2 expression, all of which were miR-34a downstream genes related with cell apoptosis. Moreover, mutant PS-2 also activated the p53/miR-34a axis and induced apoptosis in AD transgenic mice brain. These results implied that mutant PS-2 might promote the apoptosis of neuronal cells through triggering the p53/miR-34a axis. Altogether our results provide a novel insight into neurodegenerative disease and deepen our understandings of AD pathogenic processes.

[Correlation between serum adiponectin level and cognitive function in patients with Alzheimer's disease].

OBJECTIVE: To investigate serum adiponectin level in patients with Alzheimer's disease (AD) and its correlation with the patients' cognitive function. METHODS: This case-control study was conducted in 90 patients with a highly probable diagnosis ofAD, who were divided into mild, moderate and severe group saccording to the MMSE score. Ninety healthy subjects matched for age and gender with the AD patients were selected as the control group. The serum levels ofadiponectin in the participants were detected using enzyme-linked immunosorbent assay. RESULTS: Serum adiponectin level was significantly lower in the AD group than in the control group (P<0.05). Of the 3 subgroups of the AD patients, the moderate and severe AD groups showed significantly lower serum adiponectin level sthan the control group (P<0.05), but the difference in adiponectin levels was not significant between the mild AD group and the control group (P>0.05); serum adiponectin levels also differed significantly among the 3 subgroups of AD patients (P<0.05). Serum adiponectin level was positively correlated with the MMSE score in the AD patients (r=0.683, P<0.001). CONCLUSION: Serum adiponectin levels are reduced in AD patients and associated with the degree of cognitive impairment.

[Research progress of depression and the application of esketamine].

OBJECTIVE: The pathogenesis and etiology of still remain unknown. Current evidence suggests that the occurrence of depression may be related to a reduced secretion of neurotransmitters, neuronal apoptosis, inflammation, intestinal flora and other factors. Although the commonly used antidepressants such as SSRIs, SNRIs, NaSSA, and SARIs produce some therapeutic effects, they fail to relieve the full spectrum of the symptoms of depression. In recent years, esketamine was found to produce a potent and a long-lasting antidepressant effect by acting on the NMDA receptors. Herein the authors review the progress in the study of the pathogenesis and drug therapies of depression, the efficacy of esketamine treatment and the underlying mechanism, and the prospect of esketamine treatment. Currently the mechanism of the antidepressant effect of esketamine remains indeterminate and its clinical application is limited, but its effect in rapidly alleviating the symptoms of depression suggests its bright prospect for clinical applications.

[Effect of willed movement therapy on GFAP and SYP expression in rats with cerebral ischemia-reperfusion].

OBJECTIVE: To determine the effect of willed movement on the expression of glial fibrillary acidic protein (GFAP) and synaptophysin (SYP) in adult rats with cerebral ischemia-reperfusion, and explore the mechanism of willed movement in promoting nerve repair and regeneration. METHODS: Adult rat models of cerebral ischemia-reperfusion injury were established by middle cerebral artery occlusion (MCAO) for 2 h followed by a 24-h reperfusion. The models were then divided randomly into 3 groups, namely the model group, environmental modification (EM) group, and willed movement (WM) group. In each group, neurological deficits were evaluated at 3, 7 and 15 days after reperfusion. Immunohistochemistry and immunofluorescence assay were employed to examine the expression of GFAP and SYP in the brain tissue near the ischemic foci. RESULTS: The rats in WM group showed lessened neurological deficits at 15 days and lowered expression of GFAP and SYP at 7 and 15 days after reperfusion compared with the model and EM groups (P<0.05). No significant difference was found in the expression of GFAP or SYP between the model group and EM group at any time points. CONCLUSION: Willed movement can promote the functional recovery of neurological deficits following cerebral ischemia-reperfusion probably in relation to enhanced GFAP and SYP expressions in the ischemic brain tissues.

[Effect of willed movement therapy on the expression of neurotrophin 3 and growth-associated protein 43 in rats with cerebral ischemia reperfusion].

OBJECTIVE: To observe the effect of willed movement therapy on the expression of neurotrophin 3 (NT-3) and growth associated protein 43 (GAP-43) in rats with cerebral ischemia-reperfusion (IR) and investigate the neuroprotective mechanism of willed movement therapy in nerve regeneration and repair. METHODS: Cerebral IR model was established by middle cerebral artery occlusion (MCAO) in SD rats. The rats were randomly divided into MCAO group, environment modification group (EM group) and willed movement therapy group (WM group). The rats were evaluated for neurological deficits and decapitated on days 3, 7 and 15 after the reperfusion to examine the expressions of NT-3 and GAP-43 in the ischemic brain tissues by immunohistochemistry. RESULTS: Compared with MCAO and EM groups, the rats in WM group showed significantly lowered grade of neurological deficits (P<0.05) at 15 days and significantly increased the expressions of NT-3 and GAP-43 (P<0.05) at 7 and 15 days after the reperfusion. No significant difference was found in the expression of NT-3 and GAP-43 between MCAO and EM groups (P>0.05). The expression of NT-3 was positively correlated to that of GAP-43 in the ischemic tissues. CONCLUSIONS: Willed movement therapy increases the expression of NT-3 and GAP-43 in the ischemic brain area in rats with cerebral ischemia-reperfusion, which is probably related to nerve regeneration and repair.

[Butylphthalide improves learning and memory abilities of rats with Alzheimer's disease possibly by enhancing protein disulfide isomerase and inhibiting P53 expressions].

OBJECTIVE: To determine the effect of butylphthalide on the expressions of protein disulfide isomerase (PDI) and P53 in the brain tissue of rats with Alzheimer's disease (AD). METHODS: Sixty male adult rats were randomly divided into AD model group, butylphthalide group and control group (n = 20). AD models were established by injecting beta-amyloid protein 1-42 into the hippocampus of rats. Sixty days later, the learning and memory abilities of the rats were evaluated using Y-maze test, and the expressions of PDI and P53 in the brain tissue of the rats were measured by immunohistochemistry. RESULTS: Compared with the control group, the rats in AD model group exhibited significantly reduced learning and memory abilities, lowered expressions of PDI in the hippocampus and increased expression of P53 in the cortex (P > 0.01). In comparison with the model group, the rats in the butylphthalide group showed significantly increased PDI-positive cells in the hippocampus and decreased expression of P53 in the cortex (P < 0.01). CONCLUSION: Butylphthalide improves the learning and memory abilities of rats with experimental AD, the mechanism of which may involve inhibition of P53 expression and enhancement of PDI expression in the brain tissues.

[Butylphthalide improves learning and memory abilities of rats with Alzheimer's disease possibly by inhibiting P38 mitogen-activated protein kinase and enhancing extra-cellular signal regulated kinase expressions].

OBJECTIVE: To determine the effect of butylphthalide on the expressions of p38 mitogen-activated protein kinase and extra-cellular signal regulated kinases (ERKs) in the brain tissue of rats with Alzheimer's disease (AD). METHODS: Sixty male adult rats were randomly divided to AD model group, butylphthalide group, and control group (n=20). AD models were established by injecting beta-amyloid protein 1-42 into the hippocampus of rats. Sixty days later, the learning and memory abilities of the rats were evaluated using Y-maze test, and the expressions of p38 and ERKs in the brain tissue of the rats were measured by immunohistochemistry. RESULTS Compared with the control group, the rats in AD model group exhibited significantly reduced learning and memory abilities, increased expressions of P38 in the hippocampus and lowered expression of ERK in the cortex (P<0.01). In comparison with the model group, the rats in the butylphthalide group showed significantly decreased P38-positive cells in the hippocampus and increased expression of ERK in the cortex (P<0.01). CONCLUSIONS: Butylphthalide improves the learning and memory abilities of rats with experimental AD, the mechanism of which may involve inhibition of P38 expression and enhancement of ERK expression in the brain tissues.

[Effect of butylphthalide on the expression of S100 and glial fibrillary acidic protein in a rat model of Alzheimer disease].

OBJECTIVE: To determine the expression of S100-beta protein and glial fibrillary acidic protein (GFAP) in hippocampal astrocytes of rats with Alzheimer disease (AD) model rats, and observe the effect of butylphthalide on their expression. METHODS: Sixty male adult rats were randomized equally into model group, butylphthalide group, and control group, and in the former two groups, AD models were established by injecting beta-amyloid protein 1-40 into the hippocampus. Sixty days later, the rats were sacrificed and the bilateral hippocampuses were taken for immunohistochemistry. RESULTS: The number of cells positive for S100 and GFAP in the hippocampus in butylphthalide group were significantly higher than that in the control group (P/0.01), but lower than that in the model group (P/0.05). CONCLUSION: The expression of S100 protein and glial fibrillary acidic protein increased significantly in the hippocampal astrocytes of rats with AD, and butylphthalide can inhibit the increase of their expression.

Altered angiotensin-converting enzyme and its effects on the brain in a rat model of Alzheimer disease.

BACKGROUND: Alzheimer disease (AD) is a neurodegenerative disease related to aging. At present, its pathological mechanisms remain unclear. Family members of the renin-angiotensin system (RAS) play a role in neuronal plasticity, as well as formation of learning and memory. In this study, we explore the effects of altered angiotensin-converting enzyme (ACE), and investigate the possible mechanisms of perindopril, an ACE inhibitor, on brain structure and function in a rat model of AD, as well as the role that ACE plays in AD. METHODS: Sixty Sprague-Dawley rats were selected and randomly divided into 3 groups: control, AD, and perindopril. Each group consisted of 20 rats, with 10 rats for determining pathology, and the remaining 10 rats for quantifying ACE activity. The rat AD model was established by stereotactically injecting amyloid beta protein (A-beta) 1-42 into the right hippocampus. Learning and memory functions were tested using the Y-type electric maze. The number and morphology of abnormal neurons were determined by haematoxylin and eosin staining. Amyloid deposition was measured by Congo red staining. Finally, ACE activity was estimated by spectrophotometry. RESULTS: Compared with the control group, the number of times needed to escape electrical stimuli increased (23.70 +/- 3.13, P < 0.001), the number of normal neurons in the CA1 region was reduced (density of 96.5 +/- 32.6/mm, P < 0.001), amyloid deposition was obvious, and ACE activity increased ((34.4 +/- 6.6) nmol x g(-1) x min(-1), P < 0.001) in the AD group. In the perindopril group, the number of times needed to escape electrical stimuli decreased (18.50 +/- 3.66, P < 0.001), the number of abnormal neurons increased (density of CA1 neurons was 180.8 +/- 28.5/mm, P < 0.001), amyloid deposition was reduced, and ACE activity was down-regulated ((26.2 +/- 6.2) nmol x g(-1) x min(-1), P < 0.001). CONCLUSIONS: ACE activity increased in the brains of AD rats. Perindopril improved learning and memory in AD rats, which correlated with decreased ACE activity and delayed AD pathogenesis.

Effect of polygonum multiflorum on the fluidity of the mitochondria membrane and activity of COX in the hippocampus of rats with Abeta 1-40-induced Alzheimer's disease.

OBJECTIVE: To explore the effect of polygonum multiflorum on the fluidity of mitochondria membrane and activity of cytochrome oxidase (COX) in Alzheimer's disease (AD) model rats. METHODS: Forty-five SD rats were randomly divided into 3 groups: an AD model group, a control group, and a treatment group (n=15). AD model was established by injecting beta-amyloid protein (Abeta) 1-40 into the hippocampus of rats. The learning and memory abilities of rats were tested with the Y-electrical maze. The coefficient of viscosity of the hippocampal mitochondria membrane was determined by a spectrofluorometer, and the activity of COX was measured by an ultraviolet spectrophotometer. RESULTS: Compared with the control group, the learning and memory ability of the AD model group was significantly lower (P<0.01), while the coefficient of viscosity of the hippocampal mitochondria membrane of the AD model group rats was significantly higher (P<0.01), and COX activity was lower (P<0.01). Compared with the AD model group rats, the coefficient of viscosity of the hippocampal mitochondria membrane of the treatment group was significantly lower (P<0.05), and COX activity was significantly improved (P<0.05). CONCLUSION: Polygonum multiflorum could improve the fluidity of mitochondria membrane and the activity of mitochondrial COX in the model of Alzheimer's disease.