PURPOSE: To investigate the effects of hyperbaric oxygen (HBO) pretreatment on cognitive decline and neuronal damage in an Alzheimer’s disease (AD) rat model. MATERIALS AND METHODS: Rats were divided into three groups: normal saline (NS), AD, and HBO+AD. In the AD group, amyloid β peptide (Aβ)₁₋₄₀ was injected into the hippocampal CA1 region of the brain. NS rats received NS injection. In the HBO+AD group, rats received 5 days of daily HBO therapy following Aβ₁₋₄₀ injection. Learning and memory capabilities were examined using the Morris water maze task. Neuronal damage and astrocyte activation were evaluated by hematoxylin-eosin staining and immunohistochemistry, respectively. Dendritic spine density was determined by Golgi-Cox staining. Tumor necrosis factor-α, interleukin-1β, and interleukin-10 production was assessed by enzyme-linked immunosorbent assay. Neuron apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling. Protein expression was examined by western blotting. RESULTS: Learning and memory dysfunction was ameliorated in the HBO+AD group, as shown by significantly lower swimming distances and escape latency, compared to the AD group. Lower rates of neuronal damage, astrocyte activation, dendritic spine loss, and hippocampal neuron apoptosis were seen in the HBO+AD than in the AD group. A lower rate of hippocampal p38 mitogen-activated protein kinase (MAPK) phosphorylation was observed in the HBO+AD than in the AD group. CONCLUSION: HBO pretreatment improves cognition and reduces hippocampal damage via p38 MAPK in AD rats.
Alzheimer Disease/*therapy ; Amyloid beta-Peptides/*administration & dosage ; Animals ; Apoptosis ; *Cognition/drug effects ; Disease Models, Animal ; Enzyme-Linked Immunosorbent Assay ; Hippocampus/*enzymology ; *Hyperbaric Oxygenation ; In Situ Nick-End Labeling ; Interleukin-10/biosynthesis ; Interleukin-1beta/biosynthesis ; Learning/drug effects ; Male ; Memory/drug effects ; Neurons ; Peptide Fragments/*administration & dosage ; Rats ; Rats, Sprague-Dawley ; Sodium Chloride/administration & dosage ; Tumor Necrosis Factor-alpha/biosynthesis ; p38 Mitogen-Activated Protein Kinases/*metabolism

The present study was aimed to investigate the role of cerebrospinal fluid-contacting nucleus (CSF-CN) neurons in modulation of inflammatory pain and underlying mechanism. The inflammatory pain model was made by subcutaneous injection of the complete Freund's adjuvant (CFA) into the left hind paw of rats. The phosphorylation level of PKC (p-PKC) was examined by Western blot. Thermal withdrawal latency (TWL) of the rats was measured to assess inflammatory pain. The results showed that, compared with the sham controls, the inflammatory pain model rats showed shortened TWL on day 1, 3, and 7 after CFA injection, as well as increased level of p-PKC in CSF-CN neurons at 24 h after CFA injection. The administration of GF109203X, a PKC inhibitor, into lateral ventricle decreased the level of p-PKC protein expression and increased TWL in the model rats. These results suggest that blocking the PKC pathway in CSF-CN neurons may be an effective way to reduce or eliminate the inflammatory pain.
Animals ; Freund's Adjuvant ; Inflammation ; enzymology ; Neurons ; enzymology ; Pain ; enzymology ; Phosphorylation ; Protein Kinase C ; cerebrospinal fluid ; chemistry ; Rats ; Rats, Sprague-Dawley

The purpose of this research is to explore the distribution and expression of MAP kinase phosphatase-1 (MKP-1) in cerebrospinal fluid (CSF)-contacting nucleus in depression, and provide experimental evidence to reveal the biological function and regulatory mechanisms of CSF-contacting nucleus in depression. Depression model was produced by chronic forced swimming stress (CFSS) in Sprague-Dawley (SD) rats. Intracerebroventricular injection of cholera toxin subunit B (CTb) labeled with horseradish peroxidase (CB-HRP) was used to specifically mark distal CSF-contacting nucleus. The rate of animal growth and behavioral tests including sucrose preference test (SPT) and open field test (OFT) were used to validate the model of depression. The expressions of MKP-1 and fos proteins in CSF-contacting nucleus were detected by immunofluorescence. Software Image-Pro Plus version 6.0 was used to count the positive neurons. The results showed that, the distributions of MKP-1 were found in the CSF-contacting nucleus. After 28 days of swimming, the rats in stress group had a lower growth rate, a less consumption of sucrose and lower scores of OFT compared to control group. The number of neurons double labeled with CB-HRP/fos or CB-HRP/MKP-1 in stress group was significantly higher than that in control group (P < 0.01). These results suggest that the CSF-contacting nucleus may be involved in the process of depression via the MKP-1.
Animals ; Cerebrospinal Fluid ; Depression ; enzymology ; Dual Specificity Phosphatase 1 ; physiology ; Neurons ; physiology ; Rats ; Rats, Sprague-Dawley ; Stress, Physiological

Chronic spinal cord compression is the common clinical prognosis with various outcomes, but the affecting factors and mechanisms still remain unexplored. The structure and function of neurovascular unit manifest great significance in the central nervous system diseases. This paper discusses matrix metalloproteinase (MMP) impact on the stability of the neural vascular unit, by directly decomposing extracellular matrix, inducing the glial cell migration, activating angiogenesis, regulating function of blood spinal cord barrier, and put forward the MMP may be the key points in regulation of spinal cord neurovascular unit structure and function change to affect the outcome of chronic oppressive cervical spinal cord.
Cell Movement ; Humans ; Matrix Metalloproteinases ; physiology ; Nerve Compression Syndromes ; diagnosis ; enzymology ; Neurons ; cytology ; Prognosis ; Spinal Cord Injuries ; diagnosis ; enzymology

BACKGROUNDDiabetes-related pathogenic factors can cause retinal ganglion cell (RGC) apoptosis, but the specific mechanism is not very clear. The aim of this study is to investigate the correlation between glycogen synthase kinase-3 (GSK-3) activation and retinal neuron apoptosis.

METHODSIn an in vitro experiment, the number of apoptotic RGC-5 cells differentiated by staurosporine was evaluated via flow cytometry and nuclei staining using Hoechst 33258. GSK-3 phosphorylation and caspase-3 activation in RGC-5 cells after serum deprivation were determined using Western blotting. Mitochondrial membrane potential was detected using the dye 5, 5', 6, 6'tetrachloro-1, 1', 3, 3'-tetrethyl benzimidalyl carbocyanine iodide, and reactive oxygen species (ROS) levels were measured with dihydroethidium. In an in vivo experiment, the number of apoptotic retinal neurons was evaluated via terminal transferase dUTP nick-end labeling (TUNEL), and GSK-3 phosphorylation was determined using Western blotting, in the retinal nerve epithelial tissue of rats in which diabetes was induced by intravenous tail-vein injection of streptozotocin for 4 weeks.

RESULTSThe levels of phosphorylated Ser21/9 in GSK-3α/β and p-T308/S473-AKT were lower and the cleaved caspase-3 levels were higher in the serum-deprived model (P < 0.05). Lithium chloride treatment was associated with a slower rate of apoptosis, increased mitochondrial membrane potential, and decreased ROS levels in differentiated RGC-5 cells (P < 0.05). The level of blood glucose and the number of TUNEL-positive cells in the whole-mounted retinas were higher (P < 0.01), and the levels of phosphorylated Ser21/9 in GSK-3α/β and body weight were lower (P < 0.05). However, the thickness of the retinal nerve epithelial layer was not significantly less in diabetic rats compared with control group. Lithium chloride intravitreal injection increased the levels of phosphorylated Ser21/9 in GSK-3α/β and decreased TUNEL-positive cells in the whole-mounted retinas.

CONCLUSIONGSK-3 kinase is closely related to retinal neuron apoptosis, and the application of the GSK-3 inhibitor lithium chloride can reduce retinal neuron apoptosis in early diabetic retinopathy.

Animals ; Apoptosis ; genetics ; physiology ; Cell Line ; Cell Survival ; physiology ; Diabetic Retinopathy ; enzymology ; genetics ; metabolism ; Flow Cytometry ; Glycogen Synthase Kinase 3 ; genetics ; metabolism ; Male ; Neurons ; cytology ; metabolism ; Rats ; Rats, Sprague-Dawley ; Retina ; cytology ; enzymology

BACKGROUNDBrain dysfunction is a frequent complication of sepsis, usually defined as sepsis-associated encephalopathy (SAE). Although the Notch signaling pathway has been proven to be involved in both ischemia and neuronal proliferation, its role in SAE is still unknown. Here, the effect of the Notch signaling pathway involved γ-secretase inhibitor DAPT on SAE in septic rats was investigated in a cecal ligation and puncture (CLP) model.

METHODSFifty-nine Sprague-Dawley rats were randomly divided into four groups, with the septic group receiving the CLP operation. Twenty-four hours after CLP or sham treatment, rats were sacrificed and their hippocampus was harvested for Western blot analysis. TNF-α expression was determined using an enzyme-linked immunosorbent assay (ELISA) kit. Neuronal apoptosis was assessed by TUNEL staining, and neuronal cell death was detected by H&E staining. Finally, a novel object recognition experiment was used to evaluate memory impairment.

RESULTSOur data showed that sepsis can increase the expression of hippocampal Notch receptor intracellular domain (NICD) and poly (adenosine diphosphate [ADP]-ribose) polymerase-1 (PARP-1), as well as the inflammatory response, neuronal apoptosis, neuronal death, and memory dysfunction in rats. The γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine t-butyl ester (DAPT) can significantly decrease the level of NICD and PARP-1, reduce hippocampal neuronal apoptosis and death, attenuate TNF-α release and rescue cognitive impairment caused by CLP.

CONCLUSIONThe neuroprotective effect of DAPT on neuronal death and memory impairment in septic rats, which could be a new therapeutic approach for treating SAE in the future.

Amyloid Precursor Protein Secretases ; antagonists & inhibitors ; Animals ; Apoptosis ; drug effects ; Dipeptides ; therapeutic use ; Hippocampus ; drug effects ; metabolism ; Male ; Neurons ; cytology ; drug effects ; Neuroprotective Agents ; Poly (ADP-Ribose) Polymerase-1 ; Poly(ADP-ribose) Polymerases ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Notch ; metabolism ; Sepsis ; complications ; Sepsis-Associated Encephalopathy ; drug therapy ; enzymology ; Signal Transduction ; drug effects

OBJECTIVETo explore action mechanism of acupuncture and moxibustion for Alzheimer's disease (AD) to provide evidence for prevention and treatment with acupuncture and moxibustion on AD in clinic.

METHODSEighty SPF-grade male Wistar rats, (200 +/- 20) g, were randomly divided into a normal group, a sham-operation group, a model group and a treatment group, 20 cases in each one. The model was duplicated with injection of Abeta1-42 in rats' hippocampus. Expect the treatment group, the rest groups were treated with regular feeding after respective intervention. The treatment group was treated with acupuncture and moxibustion at "Baihui" (GV 20) and "Shenshu" (BL 23), once a day, seven days as a treatment course and totally for two courses. There was one day of interval between the courses. The immunohistochemistry and quantitative RT-PCR methods were applied to test level of Abeta-binding alcohol dehydrogense (ABAD) and cytochrome oxidase IV (COX IV) in hippocampal neurons mitochondria.

RESULTSAcupuncture and moxibustion could reduce effectively level of ABAD and improve activity of COX IV in hippocampal neurons mitochondria in the treatment group, which has statistical significance compared with that in the model group (P < 0.01) and no statistical significance compared with that in the normal group and sham-operation group (P > 0.05). This indicated that acupuncture and moxibustion could effectively suppress overexpression of ABAD, improve activity of COX IV and reduce leak of reactive oxygen species, which could improve metabolic disturbance of mitochondria energy to achieve the goal of prevention and treatment of AD.

CONCLUSIONThe prevention and treatment of AD with acupuncture and moxibustion could be related with suppressing overexpression of ABAD and improving activity of COX IV in hippocampal neurons mitochondria to improve mitochondria energy metabolism.

3-Hydroxyacyl CoA Dehydrogenases ; genetics ; metabolism ; Acupuncture Therapy ; Alzheimer Disease ; enzymology ; metabolism ; therapy ; Animals ; Electron Transport Complex IV ; genetics ; metabolism ; Energy Metabolism ; Hippocampus ; cytology ; enzymology ; metabolism ; Humans ; Male ; Mitochondria ; enzymology ; metabolism ; Moxibustion ; Neurons ; enzymology ; metabolism ; Rats ; Rats, Wistar

Acute and chronic neurodegenerative diseases are illnesses associated with high morbidity and mortality, and few or no effective options are available for their treatments. Many neurodegenerative diseases are included in them, for example, stroke, brain trauma, spinal cord injury, amyotrophic lateral sclerosis (ALS), Huntington's disease, Alzheimer's disease, and Parkinson's disease. Given that central nervous system tissue has very limited, if any, regenerative capacity, it is of utmost importance to limit the damage caused by neuronal death. During the past decade, considerable progress has been made in understanding the process of cell death. In this article, we review the causes and mechanisms of neuronal-cell death, especially as it pertains to the caspases family of proteases associated with cell death. The results may be helpful to the experimental research and clinical application of neurodegenerative diseases.
Animals ; Apoptosis ; physiology ; Caspases ; metabolism ; Cell Death ; Humans ; Neurodegenerative Diseases ; enzymology ; pathology ; Neurons ; pathology ; Peptide Hydrolases ; metabolism

In order to explore the possible mechanism of EA (Electroacupuncture) in improving cognitive impairment, the present study was to research the effect of EA on the behavior and expression of the hippocampal neuronal nitric oxide synthase (nNOS) protein of the ovariectomized rats. Forty female SD rats were randomly and equally divided into four groups: sham group (ovarian fat around removal), model group (ovariectomy), sham EA group (sham EA stimulation after ovariectomy) and EA group (EA stimulation after ovariectomy). Two weeks after the ovariectomy, EA and sham EA were applied continuously for 3 months. In the experiment, Morris water maze was used to test the ability of spatial learning and memory, while enzyme-linked immuno sorbent assay (ELISA) and Western blot (WB) were used to detect the concentration of serum estradiol (E2) and relative expression of nNOS protein. The results showed that the escape latency of the EA and sham EA groups was shortened and the number of platform-crossing was significantly increased. The concentration of serum E2 and the expression of nNOS protein in both EA group and sham EA group were significantly elevated compared to those in the model group, while increment in the EA group was more significant (P<0.01). It could be concluded that from above experimental results, EA could be capable of improving learning and memory in ovariectomized rats by promoting the expression of nNOS protein through increasing the concentration of estrogen.
Animals ; Behavior, Animal ; Cognition Disorders ; prevention & control ; Electroacupuncture ; Estradiol ; blood ; Female ; Hippocampus ; enzymology ; Learning ; Memory ; Neurons ; enzymology ; Nitric Oxide Synthase Type I ; metabolism ; Ovariectomy ; adverse effects ; Rats ; Rats, Sprague-Dawley

P21-activated kinases (PAK) participate in a variety of important cellular activities, such as cytoskeleton remodeling, cell migration, cell cycle regulation, and apoptosis or survival. PAK also has an important impact on brain development, neuronal differentiation, and regulation of synaptic plasticity in the nervous system. PAK abnormalities result in diseases including cancer, Parkinson's disease (PD), Alzheimer's disease (AD) and neural retardation. Therefore, it is of vital physiological significance to investigate the neuronal function of PAK. In this paper we review the advancement of research on the neuronal biological function and the underlying mechanisms of PAK.
Alzheimer Disease ; physiopathology ; Apoptosis ; Cell Cycle ; Cell Movement ; Cytoskeleton ; physiology ; Humans ; Nervous System ; enzymology ; Neuronal Plasticity ; Neurons ; physiology ; Parkinson Disease ; physiopathology ; p21-Activated Kinases ; physiology