Background: The hippocampus is a key brain area for many forms of learning and memory and is particularly sensitive to changes in glucose homeostasis. Aim of the work: To investigate in experimentally induced type 1 and 2 diabetes mellitus in rat model the effect of  diabetes mellitus on cognitive functions and related markers of hippocampal synaptic plasticity, and the possible impact of blocking N-methyl-D-aspartic acid (NMDA) receptors by memantine. Materials and methods: Seven rat groups were included: non-diabetic control and non-diabetic receiving memantine; type-1 diabetic groups - untreated, treated with insulin alone and treated with insulin and memantine; and type 2 diabetic groups - untreated and memantine treated. Cognitive functions were assessed by the Morris Water Maze and passive avoidance test. Biochemical analysis was done for serum glucose, serum insulin and insulin resistance. Routine histological examination was done, together with immunohistochemistry for detection of the hippocampal learning and memory plasticity marker, namely activity regulated cytoskeletal-associated protein (Arc), and the astrocytes reactivity marker, namely glial fibrillary acidic protein (GFAP).  Results: Both type 1 and 2 untreated diabetic groups showed significantly impaired cognitive performance compared to the non-diabetic group. Treating the type 1 diabetic group with insulin alone significantly improved cognitive performance, but significantly decreased GFAP and Arc compared to the untreated type 1 group. In addition, the type 2 diabetic groups showed a significant decrease in hippocampus GFAP and Arc compared to the non-diabetic groups. Blocking NMDA receptors by memantine significantly increased cognitive performance, GFAP and Arc in the type 1 insulin-memantine group compared to the type 1-insulin group and significantly increased Arc in the type 2-memantine group compared to the untreated type 2 diabetic group. The non-diabetic group receiving memantine was, however, significantly adversely affected. Conclusion: Cognitive functions are impaired in both types of diabetes mellitus and can be improved by blockage of NMDA receptors which may spark a future therapeutic role for these receptors in diabetes-associated cognitive dysfunction.

Neurocognitive outcome affects the quality of life of ALL survivors. This study is aimed to assess the prevalence of neurocognitive dysfunction by psychometric and imaging tools in survivors of childhood ALL, treated with 3 different protocols and the effect of time elapsed since the end of chemotherapy. Sixty-two ALL survivors aged 6-18 years and treated in the period 1997-2007 and 60 healthy age and sex matched controls were subjected to neurocognitive testing using Wechsler Intelligence Scale for Children, Benton visual retention (BVRT) and Trail Making test (TMT), followed by diffusion weighed and diffusion tensor MRI for calculation of fraction anisotropy (FA). Survivors underwent revision of protocol and type of CNS therapy. Three different protocols were used: modified BFM 83, BFM 90, and CCG. Survivors treated with modified CCG protocol showed a significant decrease in all cognitive tests compared to control (p<.05); BFM 90 group had a significant lower IQ and longer TMT compared to both control and BFM 83 group and no significant difference was found in results of cognitive tests between BFM 83 and control group. Frontal FA was lower in CCG treated group compared to control, BFM 90 and BFM 83 groups (p<.05); meanwhile it was significantly lower in BFM 90 and BFM 83 groups compared to control group. We concluded that patients treated with modified CCG protocol showed the worst neurocognitive outcome among three assessed protocols. Frontal lobe FA might be an early marker for predicting the neurotoxicity in childhood ALL survivors.

The potential inhibitory effect of the antidiabetic and anti‐inflammatory drug, metformin on thioacetamide (TAA)‐induced hepatotoxicity associated with the inhibition of mammalian target of rapamycin (mTOR)–hypoxia‐inducible factor‐1α (HIF‐1α) axis has not been investigated before. Therefore, we tested whether metformin can protect against liver injuries including fibrosis induced by TAA possibly via the downregulation of mTOR–HIF‐1α axis and profibrogenic and inflammatory biomarkers. Rats either injected with TAA (200 mg/kg; twice a week for 8 weeks) before being killed after 10 weeks (model group) or were pretreated with metformin (200 mg/kg) daily for 2 weeks before TAA injections and continued receiving both agents until the end of the experiment, at Week 10 (protective group). Using light and electron microscopy examinations, we observed in the model group substantial damage to the hepatocytes and liver tissue such as collagen deposition, infiltration of inflammatory cells, and degenerative cellular changes with ballooned mitochondria that were substantially ameliorated by metformin. Metformin also significantly ( p < 0.05) inhibited TAA‐induced HIF‐1α, mTOR, the profibrogenic biomarker α‐smooth muscle actin, tissue inhibitor of metalloproteinases‐1, tumor necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), alanine aminotransferase (ALT) and aspartate aminotransferase in harvested liver homogenates and blood samples. In addition, a significant ( p < 0.01) positive correlation between hypoxia scoring (HIF‐1α) and the serum levels of TNF‐α ( r = 0.797), IL‐6 ( r = 0.859), and ALT ( r = 0.760) was observed. We conclude that metformin protects against TAA‐induced hepatic injuries in rats, which is associated with the inhibition of mTOR–HIF‐1α axis and profibrogenic and inflammatory biomarkers; thus, may offer therapeutic potential in humans.

Diabetes Mellitus is a chronic generalized disorder due to insulin insufficiency or resistance. Skeletal muscles represent one of the most important target organs that is affected by insulin signaling. The aim of the current work was to investigate the effect of metformin versus vitamin D (and also simultaneous administration) therapy in type 2 diabetic (T2D) rats on the state of the muscle and insulin sensitivity. Thirty six male rats constituted the animal model and have been divided into five groups: control, Diabetic, Diabetic + Metformin, Diabetic + Vitamin D, Diabetic + Metformin + Vitamin D. Blood samples were taken for biochemical measurements of serum calcium, interleukin-6 (IL-6), Triglycerides (TG), glucose, insulin, and calculation of HOMA-IR, and then rats were sacrificed, dissected for removal of gastrocnemius muscle that is used for both biochemical, histopathological and electron microscopy examination. Oral administration of vitamin D alone or in combination with metformin improved insulin sensitivity in skeletal muscles, and sustained the metabolic complications along with muscle atrophy and inflammation in T2D rats. We demonstrated super-beneficial action on insulin resistance of additional vitamin D therapy in T2DM rats that were insufficiently controlled by metformin alone.

Stress is any condition that impairs the balance of the organism physiologically or psychologically. The response to stress involves several neurohormonal consequences. Glutamate is the primary excitatory neurotransmitter in the central nervous system, and its release is increased by stress that predisposes to excitotoxicity in the brain. Memantine is an uncompetitive N-methyl D-aspartate glutamatergic receptors antagonist and has shown beneficial effect on cognitive function especially in Alzheimer's disease. The aim of the work was to investigate memantine effect on memory and behavior in animal models of acute and repeated restraint stress with the evaluation of serum markers of stress and the expression of hippocampal markers of synaptic plasticity. Forty-two male rats were divided into seven groups (six rats/group): control, acute restraint stress, acute restraint stress with Memantine, repeated restraint stress, repeated restraint stress with Memantine and Memantine groups (two subgroups as positive control). Spatial working memory and behavior were assessed by performance in Y-maze. We evaluated serum cortisol, tumor necrotic factor, interleukin-6 and hippocampal expression of brain-derived neurotrophic factor, synaptophysin and calcium-/calmodulin-dependent protein kinase II. Our results revealed that Memantine improved spatial working memory in repeated stress, decreased serum level of stress markers and modified the hippocampal synaptic plasticity markers in both patterns of stress exposure; in ARS, Memantine upregulated the expression of synaptophysin and brain-derived neurotrophic factor and downregulated the expression of calcium-/calmodulin-dependent protein kinase II, and in repeated restraint stress, it upregulated the expression of synaptophysin and downregulated calcium-/calmodulin-dependent protein kinase II expression.

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Stress affects multiple organs in the body in addition to the brain including the liver. We aimed to assess the effects of blocking N-methyl-D-aspartate (NMDA) glutamate receptors by memantine on the liver in acute and repeated restraint stress. Forty two male albino rats divided into seven groups; control, Acute restraint stress (ARS), ARS+memantine, repeated restraint stress, repeated restraint +memantine and positive control groups. We measured serum iron, zinc, alanine transferase and Aspartame transferase, hepatic malondialdehyde, tumor necrosis factor-alpha (TNF-α), glutathione peroxidase, Superoxide dismutase, metallothionein content, zinc transporter ZRT/IRT-like Protein 14 mRNA expression, hepcidin expression. We had a histopathological evaluation by histological staining and immunostaining for glial fibrillary acidic protein and synaptophysin expression as markers of hepatic stellate cells (HSCs) activation. Both ARS and repeated stress increased markers of hepatic cell injury, oxidative stress, and HSCs activation. Blocking NMDA by Memantine offered hepatoprotective effect in acute and repeated restraint stress and decreased hepatic cell injury, oxidative stress, and HSCs activation. KEYWORDS:Acute stress repeated stress, Restraint, liver, memantine In the current study, we explored the effects of acute and repeated restraint stress on the liver and the impact of blocking NMDA receptors by the memantine (the uncompetitive NMDA receptor antagonist) on the markers of hepatocellular injury, oxidative stress, and hepatic stellate cells (HSCs) activation. -METHODS: I-Experimental Animals:The experimental procedures, animal handling, sampling, and scarification were done according to the Guide for the care and use of laboratory animals, Eighth Edition (2011) B) Determination of liver functionsSerum ALT and AST were determined enzymatically using commercially available kits (Bioclin, Santa Coloma, Spain). C) Measurement of MDATissue MDA was determined using the thiobarbituric acid reactive substance assay, according to Wills (1987).Briefly; a tissue specimen of 0.1 g was homogenized in 0.15 mol KCl at a ratio of 1-9 ml with a glass homogeniser. One volume of homogenate was mixed with two volumes of a stock solution of 20% w/v trichloroacetic acid, 0.375% w/v thiobarbituric acid and 0.25 mol hydrochloric acid. The solution was heated for 15 min in a boiling water bath. After cooling, the precipitate was removed by centrifugation at 1000 g for 10 min.The absorbance of the clear supernatant was determined at 535 nm and MDA concentration calculated using the standard curve. The cDNA was synthesized from 1 µg RNA using SuperScript III First-Strand Synthesis System as described in the manufacturer's protocol (Invitrogen, Life Technologies). In brief, one µg of total RNA mixed with 50 µM oligo (dT)20, 50 ng/µL random primers, and ten mM dNTP mix in a total volume of 10 µL. The mixture incubated at 56 °C for 5 min, then placed on ice for 3 min. The reverse transcriptase master mix containing 2 µL of 10× RT buffer, ...

Acute restraint stress (ARS) is an unavoidable stress situation and may be encountered in different clinical situations. The aim of the current study was to investigate the effects of ARS on the hippocampus and cerebellum, assess the impact of these effects on the behavior and cognitive function, and determine whether pretreatment with ceftriaxone would attenuate the damages produced by ARS on the hippocampus and cerebellum. Four groups of male mice were included in this study: The control group, ARS group, ceftriaxone group, and ARS + ceftriaxone group. Tail suspension test, Y-maze task, and open field tests were used to assess depression, working spatial memory, and anxiety. The biochemical analyses included measurements of serum cortisol, tumor necrotic factor (TNF), interleukin-6, hippocampal expression of bone morphogenetic protein 9 (BMP9), lysosomal-associated membrane protein 1 (LAMP1), glutamate transporter 1 (GLT1), heat shock protein 90, cerebellar expression of S100 protein, glutamic acid decarboxylase (GAD), and carbon anhydrase. Histopathological examination of the brain sections was conducted on the hippocampus and cerebellum by hematoxylin and eosin stains in addition to ultrastructure evaluation using electron microscopy. Our results suggested that ceftriaxone had neuroprotective properties by attenuating the effects of ARS on the hippocampus and cerebellum in mice. This effect was demonstrated by the improvement in the cognitive and behavioral tests as well as by the preservation of the hippocampal and cerebellar architecture.