INTRODUCTION:Parkinson's disease (PD) is a progressive neurological disorder characterized by the loss of dopaminergic neurons in the substantia nigra and is associated with neuroinflammation, apoptosis, oxidative stress, and motor impairment. Imipramine, a tricyclic antidepressant, has a wide range of biological effects such as anti-inflammatory, anti-apoptotic, and free radical scavenging activities. The present study was designed to investigate the neuroprotective effect of imipramine in a rat model of PD induced by 6-hydroxydopamine (6-OHDA). METHODS:Male Wistar rats were treated with daily intraperitoneal administration of imipramine (20 mg/kg, for 14 days) starting 72 h after 6-OHDA injection (20 μg/rat; 4 μl in the right medial forebrain bundle (MFB)). The motor performance was assessed using the rotarod, beam, pole, and apomorphine-induced rotation tests. The protein levels of neurotrophic factors (BDNF, GDNF, and NT3) and factors involved in oxidative stress (MDA, CAT, SOD, GST, and GSH) were measured in the striatum by ELISA technique. The neuronal survival was also evaluated by Nissl staining. RESULTS:Our results showed that 6-OHDA caused motor impairments and neuronal cell death. It also significantly reduced the protein levels of neurotrophic factors and induced an oxidative stress response in the striatum of rats. Whereas, imipramine treatment effectively reduced 6-OHDA-induced motor deficits and neuronal cell death. This improvement was accompanied by an increase in neurotrophic factors, especially GDNF, as well as a reduction in oxidative stress through increased SOD levels. CONCLUSION:These findings provide direct evidence that imipramine treatment contributes to improve of neuronal cell death and motor deficits, perhaps by increasing the striatal levels of SOD and GDNF, which play a key role in the survival of dopaminergic neurons. Further studies are also needed to elucidate the precise underlying molecular mechanisms of neuroprotective effects of imipramine.

Background: Alzheimer's ' s disease (AD) is linked to the accumulation of A beta, beta , increased tau hyperphosphorylation, persistent neuroinflammation, and a decline in neurotrophic factors, neurogenesis, and synaptic plasticity. Oxytocin (OT) has a significant impact on memory and learning. We examined the influence of intranasal (IN) OT on synaptic plasticity, neurogenesis, histone acetylation, and spatial and cognitive memories in rats. Methods: A beta 25-35 (5 mu g/2.5 mu l) was administered bilaterally in the CA1 of male Wistar rats for four consecutive days. After seven days of recovery, OT (2 mu g/ mu l, 10 mu l in each nostril) was administered IN for seven consecutive days. Working, spatial, and cognitive memories, and gene expression of neurogenesis- and synaptic plasticity- involved factors were measured in the hippocampus. Histone acetylation (H3K9 and H4K8) was also measured using western blotting. Results: IN administration of OT significantly improved working and spatial memory impairment induced by A beta beta and increased the factors involved in synaptic plasticity (MeCP2, REST, synaptophysin, and BDNF) and neurogenesis (Ki67 and DCX). We also found an enhancement in the levels of H3K9ac and H4K8ac following OT administration. Conclusion: These findings indicated that IN OT could improve hippocampus-related behaviors by increasing synaptic plasticity, stimulating neurogenesis, and chromatin plasticity.

Introduction: Methamphetamine (MA) induces cell death through several mechanisms. Insulin has an important role in cell proliferation and apoptosis via GSK3 beta inactivation. Here, we evaluated the effect of insulin and SB-216763, a selective GSK3 beta inhibitor, on MA-induced cell death in neuroblastoma SH-SY5Y, and rat primary midbrain cells. Methods: Human SH-SY5Y and rat primary midbrain cells extracted from E14.5 rat embryo were treated with insulin (0.005-0.15U) or SB-216763 (0.5-9 mu M) with or without MA (5mM). The cell viabil-ity was assessed after 24, 48, and 72 h. TNF alpha, Bax, Bim, and Bcl2 genes expression were exam-ined in primary midbrain cells after 72 h of treatment with 5mM MA, insulin (0.05U), and SB-216763 (3 mu M). Results: MA significantly decreased the viability of human SH-SY5Y and rat primary midbrain cells, and insulin and SB-216763 could increase it. In addition, elevated expression of TNF alpha and Bax fol-lowing MA was attenuated by insulin and SB-216763 in primary midbrain cells. Conclusion: These findings demonstrated that MA decreases the cell viability of rat primary midbrain cells, at least in part, by upregulation of inflammatory and apoptotic factors, and treatment with insulin and SB-216763 could attenuate MA toxicity.

Pistachio green hull extract (PGHE), an agro-industrial by-product, is rich in phenolic compounds with significant inherent antioxidant and anti-inflammatory activities. In this study, the neuroprotective effects of PGHE against Parkinson's disease (PD), a progressive neurodegenerative disorder, were evaluated both in vivo and in vitro. The lethal dose (LD50) of PGHE was greater than 5000 mg/kg, indicating its safety and nontoxicity. Rats were orally treated with PGHE (800 mg/kg/day) 24 h after injection of 6-OHDA (20 μg/rat in right MFB) for 14 days. Motor function was evaluated on Days 7 and 15 after 6-OHDA administration using the cylinder, narrow beam, pole, rotarod, and apomorphine-induced rotations tests. PGHE significantly improved motor impairments induced by 6-OHDA. An in vitro study indicated that increasing concentrations of PGHE up to 250 μg/mL resulted in a reduction in the aggregation of α-synuclein characterized by thioflavin T fluorescence and Congo red assays. Transmission electron microscopy images further confirmed a decrease in α-synuclein aggregation in the presence of PGHE. In conclusion, these findings indicated that PGHE improved motor deficits in a rat model of PD and decreased α-synuclein aggregation in vitro, suggesting that it can be considered a novel dietary supplement for PD therapy. However, more studies are needed to clarify the underlying mechanisms of PGHE's effect on PD pathogenesis and its potential applications in developing functional foods or nutraceuticals.

Background Post-traumatic stress disorder (PTSD) is a debilitating mental illness that arises after experiencing traumatic events. Insulin is involved in several nervous system functions through widespread receptors across the central nervous system (CNS). We aimed to study the effects of intranasally delivered insulin on behavioral impairments in an animal model of PTSD. Methods The single prolonged stress (SPS) protocol, which involved 2 h of restraint, 20 min of forced swimming, and exposure to vaporized diethyl ether, was used to induce PTSD-like symptoms in adult male rats. Insulin was administered intranasally (1 IU/day, 5 μl in each nostril) for 14 consecutive days. Anxiety- and depressive-like behaviors were evaluated by the elevated plus maze (EPM) and forced swimming test (FST), respectively. Short-term memory (STM) and long-term memory (LTM) were also assessed using passive avoidance. The protein levels of factors involved in oxidative stress and neuroinflammation, neurotrophic factors, and corticosterone were measured in the hippocampus by ELISA. Results Intranasal administration of insulin reduced anxiety- and depressive-like behaviors and LTM impairment induced by SPS. Increased levels of corticosterone, ROS, and TNFα, and levels and decreased levels of SOD, catalase, BDNF, and GDNF were observed in the hippocampus of PTSD-modeled animals. Insulin could reduce oxidative stress and enhance the levels of neurotrophic factors. Conclusion These findings suggest that intranasal administration of insulin early after trauma could lead to anxiolytic and antidepressant effects through the likely mechanism of modulating oxidative stress and neurotrophic factors.

Introduction: Toll-like receptor (TLR) 4 is involved in neuroinflammatory processes in peripheral tissues and central nervous system. Pro-inflammatory cytokines production, due to over activation of TLR4, interfere with insulin signaling elements lead to insulin resistance. Regarding the critical roles of TLR4 and insulin in the pathogenesis of Parkinson's disease (PD), in the present study the TLR4/insulin receptor interaction was assessed in a neuroinflammation model of PD. Methods: LPS was injected into the right striatum of male Wistar rats (20 mu g/rat). Insulin (2.5IU/ day), insulin receptor antagonist (S961; 6.5nM/kg), or TLR4 antibody (Resatorvid (TAK242); 0.01 mu g/rat) were administered intracerebroventricularly (ICV) for 14 days. Insulin and TAK242 were also simultaneously injected in a distinct group. Behavioral assessments were performed using rotarod, apomorphine-induced rotation, and cylinder tests. The levels of alpha-synuclein, TLR4, and elements of the insulin signaling pathway were measured in the striatum. Results: LPS impaired motor performance of the animals and increased the levels of alpha-synuclein and TLR4. Furthermore, it reduced mRNA levels of IRS1 and IRS2 and enhanced GSK3 beta mRNA and protein levels, indicating the development of insulin resistance. Treatment with insulin and TAK 242 improved motor deficits, restored insulin signaling pathway, and reduced alpha-synuclein and TLR4 levels. Conclusion: The findings indicate that LPS impaired motor function, at least in part, via alpha-synuclein and TLR4 overexpression, leading to insulin resistance. Suppression of TLR4 and activation of insulin receptors attenuated motor deficits, suggesting that TLR4 and insulin receptors are promising therapeutic targets for PD modification.

Interferon beta (IFNβ) is a member of the type-1 interferon family and has various immunomodulatory functions in neuropathological conditions. Although the level of IFNβ is low under healthy conditions, it is increased during inflammatory processes to protect the central nervous system (CNS). In particular, microglia and astrocytes are the main sources of IFNβ upon inflammatory insult in the CNS. The protective effects of IFNβ are well characterized in reducing the progression of multiple sclerosis (MS); however, little is understood about its effects in other neurological/neurodegenerative diseases. In this review, different types of IFNs and their signaling pathways will be described. Then we will focus on the potential role and therapeutic effect of IFNβ in several CNS-related diseases such as Alzheimer’s disease, Parkinson’s disease, Huntington's disease, amyotrophic lateral sclerosis, stroke, spinal cord injury, prion disease and spinocerebellar ataxia 7.

Background: Insulin resistance is an important pathological hallmark of Parkinson’s disease (PD). Proinflammatory cytokines during neuroinflammation decrease insulin sensitivity by suppressing insulin signaling elements. Toll-like receptor 4 (TLR4), the main receptor involved in neuroinflammation, is also associated with the pathogenesis of PD. Objectives: The present study evaluated the effect of insulin, an insulin receptor antagonist, and a TLR4 inhibitor on behavioral deficits and insulin resistance induced by 6-hydroxydopamine (6-OHDA). Methods: Male Wistar rats were divided into nine groups: (1) sham (normal saline [NS] in the medial forebrain bundle [MFB]); (2) 6-OHDA (20 µg in the MFB); (3) 6-OHDA + NS; (4) 6-OHDA + dimethyl sulfoxide (DMSO); (5) 6-OHDA + insulin (2.5 IU/day, intracerebroventricular ([ICV]); (6) 6-OHDA + insulin (5 IU/day, intranasal [IN]); (7) 6-OHDA + insulin receptor antagonist (S961; 6.5 nM/kg, ICV); (8) 6-OHDA + TLR4 inhibitor (TAK242; 0.01 µg/rat, ICV); (9) 6-OHDA + insulin + TLR4 inhibitor. All treatments were administered for seven consecutive days. Motor performance was evaluated using apomorphine-induced rotation and cylinder tests. Gene expression and protein levels of α-synuclein, TLR4, insulin receptor substrate (IRS) 1, IRS2, and glycogen synthase kinase 3β (GSK3β) were measured by real-time PCR and western blotting, respectively, in the striatum. Results: Insulin, alone and with TAK242, improved motor deficits induced by 6-OHDA. Administration of the insulin receptor antagonist had no effect on motor deficits. The increased expression of α-synuclein and TLR4 following 6-OHDA was attenuated by insulin and TAK242. GSK3β levels, both mRNA and protein, were significantly increased by 6-OHDA and attenuated with insulin and TAK242. Conclusions: The findings suggest that 6-OHDA induces neurodegeneration via activation of TLR4 and GSK3β, indicating insulin resistance, and that insulin can improve these impairments. Moreover, TLR4 inhibition prevents insulin signaling dysfunction and improves behavioral and molecular impairments, highlighting the critical role of TLR4 in the development of insulin resistance in PD pathology.

Alzheimer's disease (AD) is a common neurodegenerative disorder characterized by progressive cognitive decline. Yttrium oxide nanoparticles (Y2O3NPs) have recently attracted much attention for their potential anti-inflammatory and antioxidant properties. However, the effects of Y2O3NPs in animal models of AD are less studied. This study aimed to investigate the potential therapeutic effects of Y2O3NPs in streptozotocin (STZ)-treated rats, a reliable animal model of AD, with special emphasis on cognitive function, neuroinflammation, and mitochondrial biogenesis in the hippocampus. Male Wistar rats were stereotaxically injected with STZ (3 mg/kg, 3 µl/ventricle). Three weeks after STZ injection, cognitive function was assessed using the Morris water maze, elevated plus maze, and passive avoidance tasks. Intraperitoneal treatment with Y2O3NPs (0.1, 0.3, or 0.5 mg/kg) was started 24 h after the STZ injection and continued for 21 days. The mRNA and protein levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) and components involved in mitochondrial biogenesis (PGC-1α, NRF-1, and TFAM) were measured in the hippocampus. The results indicated that STZ induced cognitive impairment and led to neuroinflammation and mitochondrial biogenesis impairment in the hippocampus of rats. Interestingly, treatment with Y2O3NPs effectively reduced STZ-induced cognitive deficits in a dose-dependent manner, possibly by attenuating neuroinflammation and mitochondrial biogenesis impairment. These findings suggest that Y2O3NPs can be considered as a promising therapeutic agent for treating or ameliorating the neuropathological effects associated with AD.

Methamphetamine (MA) induces neurocognitive effects via several mechanisms. In the present study, we investigated the alteration of thyroid hormone receptor's expression in the context of MA-induced memory impairment and explored the protective effects of exogenous thyroid hormones (THs). Male wistar rats, received increasing regimen of MA (1-10 mg/kg, intraperitoneal, twice a day for 10 days), were treated with T3 (40 μg/rat/day; intranasal, 2.5 μl/nostril) or T4 (20 µg/kg/day; intraperitoneal) for 7 days after MA cessation. All rats were subjected to novel object recognition memory test and then the mRNA levels of TH nuclear receptors (TRα1 and TRβ1) and seladin-1, an anti-apoptotic factor, and the protein level of TH cell surface receptor (integrin αvβ3) were measured in the hippocampus of rats. Our results showed that MA-induced memory impairment is concomitant with decreased level of TRα1 mRNA. T3 or T4 treatment significantly alleviated MA-induced memory impairment, but had no significant effect on the mRNA levels of TH nuclear receptors. However, T4 treatment significantly increased the protein level of cell surface receptor (αv subunit) in MA-treated rats. These findings suggest that MA neurocognitive effects can be associated with impaired TH signaling in the brain and introduce this pathway as a promising therapeutic approach against MA-induced memory impairment.

Here, we introduced a patient with Mn-induced parkinsonism who was responsive to intranasal insulin, and his parkinsonism and dystonia responded to this treatment.

Tramadol, a weak agonist of mu-opioid receptors, causes seizure via several mechanisms. Preconditioning has been purposed to reduce the epileptic seizures in animal models of epilepsy. The preconditioning effect of tramadol on seizure is not studied yet. This study was designed to evaluate the preconditioning effect of ultra-low dose of tramadol on the seizures induced by tramadol at high dose. Furthermore, regarding the critical role of glutamate signaling in the pathogenesis of epilepsy, the effect of preconditioning on some glutamate signaling elements was also examined. Male Wistar rats received tramadol (2 mg/kg, i.p) or normal saline (1 mL/kg, i.p) in preconditioning and control groups, respectively. After 4 days, the challenging tramadol dose (150 mg/kg) was injected to all rats. Epileptic behaviors were recorded during 50 min. The expression of Norbin (as a regulator of metabotropic glutamate receptor 5), Calponin3 (as a regulator of excitatory synaptic markers), NR1 (NMDA receptor subunit 1) and GluR1 (AMPA receptor subunit 1) was measured in hippocampus, prefrontal cortex (PFC) and amygdala. Preconditioning decreased the number and duration of tremors and tonic-clonic seizures. Norbin, Calponin3, NR1 and GluR1 expression were decreased in hippocampus, and preconditioning had no effect on them. In contrast, it increased Norbin expression in PFC and amygdala, and attenuated NR1 and GluR1 upregulation following tramadol at high dose. These findings indicated that preconditioning by ultra-low dose of tramadol protected the animals against seizures following high dose of tramadol mediated, at least in part, by Norbin up regulation, and NR1 and GluR1 down regulation.

Experimental and clinical evidences demonstrate that common dysregulated pathways are involved in Parkinson’s disease (PD) and type 2 diabetes. Recently, insulin treatment through intranasal (IN) approach has gained attention in PD, although the underlying mechanism of its potential therapeutic effects is still unclear. In this study, we investigated the effects of insulin treatment in a rat model of PD with emphasis on mitochondrial function indices in striatum.

Adult neurogenesis in the hippocampal dentate gyrus plays a critical role in learning and memory. Projections originating from entorhinal cortex, known as the perforant pathway, provide the main input to the dentate gyrus and promote neurogenesis. However, neuromodulators and molecular changes mediating neurogenic effects of this pathway are not yet fully understood. Here, by means of an optogenetic approach, we investigated neurogenesis and synaptic plasticity in the hippocampus of adult rats induced by stimulation of the perforant pathway. The lentiviruses carrying hChR2 (H134R)-mCherry gene under the control of the CaMKII promoter were injected into the medial entorhinal cortex region of adult rats. After 21 days, the entorhinal cortex region was exposed to the blue laser (473 nm) for five consecutive days (30 min/day). The expression of synaptic plasticity and neurogenesis markers in the hippocampus were evaluated using molecular and histological approaches. In parallel, the changes in the gene expression of insulin and its signaling pathway, trophic factors, and components of mitochondrial biogenesis were assessed. Our results showed that optogenetic stimulation of the entorhinal cortex promotes hippocampal neurogenesis and synaptic plasticity concomitant with the increased levels of insulin mRNA and its signaling markers, neurotrophic factors, and activation of mitochondrial biogenesis. These findings suggest that effects of perforant pathway stimulation on the hippocampus, at least in part, are mediated by insulin increase in the dentate gyrus and subsequently activation of its downstream signaling pathway.

Introduction: Midbrain dopaminergic neurons are involved in various brain functions, including motor behavior, reinforcement, motivation, learning, and cognition. Primary dopaminergic neurons and also several lines of these cells are extensively used in cell culture studies. Primary dopaminergic neurons prepared from rodents have been cultured in both DMEM/F12 and neurobasal mediums in several studies. However, there is no document reporting the comparison of these two mediums. So in this study, we evaluated the neurons and astroglial cells in primary midbrain neurons from rat embryos cultured in DMEM/F12 and neurobasal mediums. Methods: Primary mesencephalon cells were prepared from the E14.5 rat embryo. Then they were seeded in two different mediums ( Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12 [DMEM/F12] and neurobasal). On day 3 and day 5, half of the medium was replaced with a fresh medium. On day 7, β3-tubulin-, GFAP (Glial fibrillary acidic protein)- and Tyrosine Hydroxylase TH-positive cells were characterized as neurons, astrocytes, and dopaminergic neurons, respectively, using immunohistochemistry. Furthermore, the morphology of the cells in both mediums was observed under light microscopy on days 1, 3, and 5. Results: The cells cultured in both mediums were similar under light microscopy regarding the cell number, but in a neurobasal medium, the cells have aggregated and formed clustering structures. Although GFAP-immunoreactive cells were lower in neurobasal compared to DMEM/F12, the number of β3-tubulin- and TH-positive cells in both cultures was the same. Conclusion: This study’s findings demonstrated that primary midbrain cells from the E14.5 rat embryo could grow in both DMEM/F12 and neurobasal mediums. Therefore, considering the high price of a neurobasal medium, it can be replaced with DMEM/F12 for culturing primary dopaminergic neurons.

Epidermal neural crest stem cells (EPI-NCSCs) are propitious candidates for cell replacement therapy and supplying neurotrophic factors in the neurological disorders. Considering the potential remyelinating and regenerative effects of fingolimod, in this study, we evaluated its effects on EPI-NCSCs viability and the expression of neurotmphic and oligodendrocyte differentiation factors. EPI-NCSCs, extracted from the bulge of rat hair follicles, were characterized and treated with fingolimod (0, 50, 100, 200, 400, 600, 1000, and 5000 nM). The cell viability was evaluated by MTT assay at 6, 24 and 72 h. The expression of neurotrophic and differentiation factors in the cells treated with 100 and 400 nM fingolimod were measured at 24 and 120 h. Fingolimod at 50-600 nM increased the cells viability after 6 h, with no change at the higher concentrations. The highest concentration (5000nM) induced toxicity at 24 and 72 h. NGF and GDNF genes expression were decreased at 120 h, but on the contrary, brain derived neurotrophic factor (BDNF) and neurotrophin 3 (NT3) were increased by both concentrations at both time points. Oligodendrocyte markers including platelet-derived growth factor receptor A (PDGFR alpha), neuron-glial antigen 2 (NG2) and growth associated protein 43 (GAP43) were elevated at 120 h, which was accompanied with reduce in stemness markers (Nestin and early growth response 1 (EGR1)). Fingolimod increased the expression of neurotrophic factors in EPI-NCSCs, and guided them to oligodendrocyte fate. Therefore, fingolimod in combination with EPI-NCSCs, can be considered as a promising approach for demyelinating neurological disorders.

Spinal cord injury (SCI), a multifactorial disease, can lead to irreversible motor and sensory disabilities. Cell therapy in combination with pharmacological agents can be a promising approach to attenuate SCI damages. Epidermal neural crest stem cells (EPI-NCSCs) extracted from bulge hair follicle in adults are attractive candidates due to the possibility of autologous transplantation. This study evaluated the effect of EPI-NCSCs combined with astaxanthin (Ast), a potent antioxidant, on damages induced by SCI. Male rats were treated with Ast (0.2 mM) and EPI-NCSCs (10(6)/10 mu l PBS) alone and combined together after SCI contusion. Motor function was assessed by Basso, Beattie and Bresnahan (BBB) test on days 1, 3, 7, 14, 21, 28, 35 and 42 post-injury. Motor neurons number and myelin level were evaluated on days 14 and 42 using Nissl and Luxol Fast Blue staining. The gene expression of mitochondrial biogenesis involved factors (PGC1 alpha, NRF1 and TFAM) was measured by qPCR. All treatments improved motor function, with the highest BBB score in Ast + Cell compared to Ast and Cell. Decreased motor neurons number and myelin level following SCI, were increased by Ast, Cell and Ast + Cell, but combination therapy significantly had a better effect. We observed reduction in PGC1 alpha, NRF1, and TFAM expression in spinal tissue after SCI, and treatment with Cell and Ast + Cell significantly restored NRF1 and TFAM mRNA levels. These results suggested that Ast in combination with EPI-NCSCs has better effects on behavioral dysfunction, motor neuron loss and demyelination after SCI. These protective effects may be attributed to mitochondrial biogenesis activation.

Methamphetamine (MA), a highly addictive psychostimulant, produces long-lasting neurotoxic effects well proven in nigrostriatal dopaminergic neurons. Considering the similarities between pathological profile of MA neurotoxicity and Parkinson's disease (PD), some reports show that previous MA abusers will be at greater risk of PD-like motor deficits. To answer the question if repeated MA exposure causes parkinsonian-like behavior in rats, we used three regimens of MA administration and assessed the motor performance parameters immediately and over a long period after MA discontinuation. Male Wistar rats in two experimental groups were treated with escalating paradigms consisting of twice daily intraperitoneal injection of either 1-7 mg/kg or 1-14 mg/kg of MA over 14 days. The third group received twice-daily doses of 15 mg/kg of MA every other day for total number of 7 days. At the 1st, 7th, 14th, 21st, 28th, and 60th days after last injections, motor activities were evaluated using narrow beam, pole, and rotarod tests. Locomotor activity was also evaluated using open field test. Repeated-measures ANOVA indicated that over the two months period following MA exposure, drug-treated rats perform beam, pole, and rotarod tests equally well as their corresponding vehicle-treated controls. Comparison of the locomotor activity didn't show significant differences between groups. These data indicated that MA at these regimens does not cause PD-related motor deficits in rats. Since MA doses, exposure duration, and dosing intervals have been shown to affect MA-induced dopaminergic toxicity, it can be concluded that none of these regimens; are strong enough to produce measurable behavioral motor deficits in rat.