The Protective Effects of the Combination of Vitamin E and Swimming Exercise on Memory Impairment Induced by Exposure to Waterpipe Smoke

BACKGROUND

Waterpipe smoking (WP) exposure involves a negative health impact, including memory deficit, which is attributed to the elevation of oxidative stress. Vitamin E (VitE) in combination with swimming exercise exerts protective effects that prevent memory impairment. In the current study, the modulation of WP-induced memory impairment by the combined effect of VitE and swimming exercise (SE) was investigated.

METHODS

Animals were exposed to WP one hour/day, five days per week for four weeks. Simultaneously, VitE (100 mg/kg, six days/week for four weeks) was administered via oral gavage, and the rats were made to swim one hour/day, five days/week for four weeks. Changes in memory were evaluated using radial arm water maze (RAWM), and oxidative stress biomarkers were examined in the hippocampus.

RESULTS

WP exposure induced short-term/long-term memory impairment (p<0.05). This impairment was prevented by a combination of VitE with SE (p<0.05). Additionally, this combination normalized the hippocampal catalase, GPx, and GSH/GSSG ratios that were modulated by WP (p<0.05). The combination further reduced TBARs levels below those of the control group (p<0.05).

CONCLUSION

WP-induced memory impairments were prevented by the combination of VitE with SE. This could be attributed to preserving the hippocampal oxidative mechanism by combining VitE and SE during WP exposure.

Hepatoprotective effect of trypsin/chymotrypsin against olanzapine-induced non-alcoholic steatohepatitis in rats

Metabolic side effects of atypical antipsychotics are an important cause of deterioration of cognitive function and failure of drug adherence. The antifatty effect trypsin/chymotrypsin (T/C) and their mechanisms of action remain unclear. To investigate possible therapeutic effect of T/C in rat model of chronic olanzapine (OLZ) - induced hepatic steatosis. Twenty rats were divided into two groups: control (C), given distilled water, and O, given 1 mg/kg of OLZ orally daily for 7 weeks. Then, both groups were given T/C 3 enzyme activity unit (EAU)/kg orally as an add-on treatment daily for the next 5 weeks and were named T/C or T/C+O groups. Rat performance in radial arm water maze was tested twice before and after T/C treatment. We measured liver enzymes, alpha-1 antitrypsin, albumin, total protein, direct and total bilirubin, inflammatory cytokines, and lipoprotein serum levels. Liver samples were collected for histopathology and Ki67 expression. The T/C add-on caused significant reduction in OLZ-induced elevation of alanine transaminase (ALT; P < 0.01), aspartate transaminase (AST; P < 0.001), alkaline phosphatase (ALP; P < 0.05), total cholesterol (Tc; P < 0.01), low-density lipoproteins (LDL-c; P < 0.05), steatosis score (P < 0.001), hepatocyte necrosis (P < 0.01), and significantly increased Ki67 expression (P < 0.01). The T/C add-on to OLZ provided protection against hepatic steatosis, elevated enzymes, and disturbed lipid profile and increased Ki67 without disturbing memory function.

Intranasal deferoxamine can improve memory in healthy C57 mice, suggesting a partially non-disease-specific pathway of functional neurologic improvement

INTRODUCTION

Intranasal deferoxamine (IN DFO) has been shown to decrease memory loss and have beneficial impacts across several models of neurologic disease and injury, including rodent models of Alzheimer's and Parkinson's disease.

METHODS

In order to assess the mechanism of DFO, determine its ability to improve memory from baseline in the absence of a diseased state, and assess targeting ability of intranasal delivery, we treated healthy mice with IN DFO (2.4 mg) or intraperitoneal (IP) DFO and compared behavioral and biochemical changes with saline-treated controls. Mice were treated 5 days/week for 4 weeks and subjected to behavioral tests 30 min after dosing.

RESULTS

We found that IN DFO, but not IP DFO, significantly enhanced working memory in the radial arm water maze, suggesting that IN administration is more efficacious as a targeted delivery route to the brain. Moreover, the ability of DFO to improve memory from baseline in healthy mice suggests a non-disease-specific mechanism of memory improvement. IN DFO treatment was accompanied by decreased GSK-3β activity and increased HIF-1α activity.

CONCLUSIONS

These pathways are suspected in DFO's ability to improve memory and perhaps represent a component of the common mechanism through which DFO enacts beneficial change in models of neurologic disease and injury.

Efficient Expression of HIV in Immunocompetent Mouse Brain Reveals a Novel Nonneurotoxic Viral Function in Hippocampal Synaptodendritic Injury and Memory Impairment

HIV causes neurodegeneration and dementia in AIDS patients, but its function in milder cognitive impairments in virologically suppressed patients on antiretroviral therapy is unknown. Such patients are immunocompetent, have low peripheral and brain HIV burdens, and show minimal brain neuropathology. Using the model of HIV-related memory impairment in EcoHIV-infected conventional mice, we investigated the neurobiological and cognitive consequences of efficient EcoHIV expression in the mouse brain after intracerebral infection. HIV integrated and persisted in an expressed state in brain tissue, was detectable in brain monocytic cells, and caused neuroinflammatory responses and lasting spatial, working, and associative memory impairment. Systemic antiretroviral treatment prevented direct brain infection and memory dysfunction indicating the requirement for HIV expression in the brain for disease. Similarly inoculated murine leukemia virus used as a control replicated in mouse brain but not in monocytic cells and was cognitively benign, linking the disease to HIV-specific functions. Memory impairment correlated in real time with hippocampal dysfunction shown by defective long-term potentiation in hippocampal slices ex vivo and with diffuse synaptodendritic injury in the hippocampus reflected in significant reduction in microtubule-associated protein 2 and synapsin II staining. In contrast, there was no evidence of overt neuronal loss in this region as determined by neuron-specific nuclear protein quantification, TUNEL assay, and histological observations. Our results reveal a novel capacity of HIV to induce neuronal dysfunction and memory impairment independent of neurotoxicity, distinct from the neurotoxicity of HIV infection in dementia.IMPORTANCE HIV neuropathogenesis has been attributed in large measure to neurotoxicity of viral proteins and inflammatory factors produced by infected monocytic cells in the brain. We show here that HIV expression in mouse brain causes lasting memory impairment by a mechanism involving injury to hippocampal synaptodendritic arbors and neuronal function but not overt neuronal loss in the region. Our results mirror the observation of minimal neurodegeneration in cognitively impaired HIV patients on antiretroviral therapy and demonstrate that HIV is nonneurotoxic in certain brain abnormalities that it causes. If neurons comprising the cognition-related networks survive HIV insult, at least for some time, there is a window of opportunity for disease treatment.

ABCA1 Deficiency Affects Basal Cognitive Deficits and Dendritic Density in Mice

ATP-binding cassette transporter A1 (ABCA1) mediates cholesterol efflux to lipid-free apolipoproteins and regulates the generation of high density lipoproteins. Previously, we have shown that lack of Abca1 significantly increases amyloid deposition and cognitive deficits in Alzheimer’s disease model mice expressing human amyloid-β protein precursor (APP). The goal of this study was to determine if ABCA1 plays a role in memory deficits caused by amyloid-β (Aβ) oligomers and examine neurite architecture of pyramidal hippocampal neurons. Our results confirm previous findings that Abca1 deficiency significantly impairs spatial memory acquisition and retention in the Morris water maze and long-term memory in novel object recognition of APP transgenic mice at a stage of early amyloid pathology. Neither test demonstrated a significant difference between Abca1^ko and wild-type (WT) mice. We also examined the effect of intra-hippocampal infused Aβ oligomers on cognitive performance of Abca1^ko mice, compared to control infusion of scrambled Aβ peptide. Age-matched WT mice undergoing the same infusions were also used as controls. In this model system, we found a statistically significant difference between WT and Abca1^ko mice infused with scrambled Aβ, suggesting that Abca1^ko mice are vulnerable to the effect of mild stresses. Moreover, examination of neurite architecture in the hippocampi revealed a significant decrease in neurite length, number of neurite segments, and branches in Abca1^ko mice when compared to WT mice. We conclude that mice lacking ABCA1 have basal cognitive deficits that prevent them from coping with additional stressors, which is in part due to impairment of neurite morphology in the hippocampus.

Effects of an Inhibitor of Monocyte Recruitment on Recovery from Traumatic Brain Injury in Mice Treated with Granulocyte Colony-Stimulating Factor

Administration of the hematopoietic growth factor granulocyte-colony stimulating Factor (G-CSF) has been reported to enhance recovery from controlled cortical impact (CCI) in rodent models. G-CSF exerts actions in both the periphery (stimulation of hematopoiesis) and in the brain, where it serves as a neurotrophic factor, promoting neuronal survival and stimulating neural stem/progenitor cell proliferation in the hippocampus. In order to distinguish the direct CNS actions of G-CSF from its peripheral actions, experiments were designed to block the recruitment of peripheral monocytes to the site of the lesion produced by CCI. The selective C-C motif receptor 2 (CCR2) antagonist (RS504303) was co-administered with G-CSF for three days after CCI in a chimeric mouse previously transplanted with GFP-expressing (GFP+) blood stem-progenitor cells. Results: The drug significantly impaired infiltration of GFP+ bone marrow-derived cells to the frontal cortex and striatum without impeding recovery performance and hippocampal neurogenesis in the behavioral test, the Radial Arm Water Maze (RAWM). Administration of the CCR2 antagonist alone, without G-CSF, was effective in promoting recovery in RAWM. These results support the hypothesis that the direct action of G-CSF on neural cells, independent of its hematopoietic effects, is primarily responsible for enhanced recovery from CCI. In addition, this study confirms the importance of CCR2 and its ligand, monocyte chemotactic protein-1 (MCP-1), in mediating the inflammatory response following CCI.

Granulocyte colony-stimulating factor promotes behavioral recovery in a mouse model of traumatic brain injury

Hematopoietic growth factors such as granulocyte colony-stimulating factor (G-CSF) represent a novel approach for treatment of traumatic brain injury (TBI). After mild controlled cortical impact (CCI), mice were treated with G-CSF (100 μg/kg) for 3 consecutive days. The primary behavioral endpoint was performance on the radial arm water maze (RAWM), assessed 7 and 14 days after CCI. Secondary endpoints included 1) motor performance on a rotating cylinder (rotarod), 2) measurement of microglial and astroglial response, 3) hippocampal neurogenesis, and 4) measures of neurotrophic factors (brain-derived neurotrophic factor [BDNF] and glial cell line-derived neurotrophic factor [GDNF]) and cytokines in brain homogenates. G-CSF-treated animals performed significantly better than vehicle-treated mice in the RAWM at 1 and 2 weeks but not on the rotarod. Cellular changes found in the G-CSF group included increased hippocampal neurogenesis as well as astrocytosis and microgliosis in both the striatum and the hippocampus. Neurotrophic factors GDNF and BDNF, elaborated by activated microglia and astrocytes, were increased in G-CSF-treated mice. These factors along with G-CSF itself are known to promote hippocampal neurogenesis and inhibit apoptosis and likely contributed to improvement in the hippocampal-dependent learning task. Six cytokines that were modulated by G-CSF treatment following CCI were elevated on day 3, but only one of them remained altered by day 7, and all of them were no different from vehicle controls by day 14. The pro- and anti-inflammatory cytokines modulated by G-CSF administration interact in a complex and incompletely understood network involving both damage and recovery processes, underscoring the dual role of inflammation after TBI.

Hippocampal brain-derived neurotrophic factor mediates recovery from chronic stress-induced spatial reference memory deficits

Chronic restraint stress impairs hippocampal-mediated spatial learning and memory, which improves following a post-stress recovery period. Here, we investigated whether brain-derived neurotrophic factor (BDNF), a protein important for hippocampal function, would alter the recovery from chronic stress-induced spatial memory deficits. Adult male Sprague-Dawley rats were infused into the dorsal hippocampal cornu ammonis (CA)3 region with an adeno-associated viral vector containing the sequence for a short hairpin RNA (shRNA) directed against BDNF or a scrambled sequence (Scr). Rats were then chronically restrained (wire mesh, 6 h/day for 21 days) and assessed for spatial learning and memory using a radial arm water maze (RAWM) either immediately after stressor cessation (Str-Imm) or following a 21-day post-stress recovery period (Str-Rec). All groups learned the RAWM task similarly, but differed on the memory retention trials. Rats in the Str-Imm group, regardless of adeno-associated viral contents, committed more errors in the spatial reference memory domain on the single retention trial during day 3 than did the non-stressed controls. Importantly, the typical improvement in spatial memory following the recovery from chronic stress was blocked with the shRNA against BDNF, as Str-Rec-shRNA performed worse on the RAWM compared with the non-stressed controls or Str-Rec-Scr. The stress effects were specific for the reference memory domain, but knockdown of hippocampal BDNF in unstressed controls briefly disrupted spatial working memory as measured by repeated entry errors on day 2 of training. These results demonstrated that hippocampal BDNF was necessary for the recovery from stress-induced hippocampal-dependent spatial memory deficits in the reference memory domain.

Depression, anxiety-like behavior and memory impairment are associated with increased oxidative stress and inflammation in a rat model of social stress

In the present study, we have examined the behavioral and biochemical effect of induction of psychological stress using a modified version of the resident-intruder model for social stress (social defeat). At the end of the social defeat protocol, body weights, food and water intake were recorded, depression and anxiety-like behaviors as well as memory function was examined. Biochemical analysis including oxidative stress measurement, inflammatory markers and other molecular parameters, critical to behavioral effects were examined. We observed a significant decrease in the body weight in the socially defeated rats as compared to the controls. Furthermore, social defeat increased anxiety-like behavior and caused memory impairment in rats (P<0.05). Socially defeated rats made significantly more errors in long term memory tests (P<0.05) as compared to control rats. Furthermore, brain extracellular signal-regulated kinase-1/2 (ERK1/2), and an inflammatory marker, interleukin (IL)-6 were activated (P<0.05), while the protein levels of glyoxalase (GLO)-1, glutathione reductase (GSR)-1, calcium/calmodulin-dependent protein kinase type (CAMK)-IV, cAMP-response-element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) were significantly less (P<0.05) in the hippocampus, but not in the prefrontal cortex and amygdala of socially defeated rats, when compared to control rats. We suggest that social defeat stress alters ERK1/2, IL-6, GLO1, GSR1, CAMKIV, CREB, and BDNF levels in specific brain areas, leading to oxidative stress-induced anxiety-depression-like behaviors and as well as memory impairment in rats.