Metformin mitigates amyloid ß1-40-induced cognitive decline via attenuation of oxidative/nitrosative stress and neuroinflammation.

Metformin is an antidiabetic medicine widely used for management of type 2 diabetes with neuroprotective effects and promising potential to attenuate cognitive impairment. The efficacy of metformin in attenuation of Alzheimer's disease (AD) pathology has not been well-documented. Thus, this study was designed to assess protective effect of metformin against Aß1-40-instigared cognitive impairment. After intra-CA1 microinjection of aggregated Aß1-40, rats received oral metformin (50 and/or 200 mg/kg/day) for two weeks. Cognition function was analyzed in various behavioral tasks besides measurement of hippocampal oxidative stress, apoptosis, and inflammation along with H&E staining and 3-nitrotyrosine (3-NT) immunohistochemistry. Obtained data showed significant improvement of discrimination score in novel object recognition test, higher alternation score in Y maze, greater latency in passive avoidance task, and lower working and reference memory errors in radial arm maze in metformin-treated Aß-injured group. Moreover, metformin treatment attenuated hippocampal levels of nitrite, MDA, protein carbonyl, ROS, TNFα, GFAP, DNA fragmentation intensity, caspase 3 activity, AChE activity, and increased SOD activity and level of IL-10 as an anti-inflammatory factor. In addition, metformin treatment was associated with lower CA1 neuronal loss and it also decreased intensity of 3-NT immunoreactivity as an indicator of nitrosative stress. Taken together, obtained findings showed neuroprotective and anti-dementia property of metformin in male rats and this may have potential benefit in attenuation of cognitive decline and related complications in patients with neurodegenerative disorders such as AD besides diabetes mellitus.

Valproate-induced murine autism spectrum disorder is associated with dysfunction of amygdala parvalbumin interneurons and downregulation of AMPK/SIRT1/PGC1α signaling.

Autism spectrum disorder (ASD) is a neurodevelopmental condition that is characterized by difficulty in social behavior and restricted behaviors. Also, in ASD, several accompanying disorders such as anxiety are observed. Considering the important role of amygdala in the pathophysiology of ASD, the present study focused on the neuronal changes and it possible signaling pathway in amygdala. After prenatal exposure to valproate (VPA; 600 mg/kg, i.p, on embryonic day 12.5), amount of ROS, MMP, caspase-3 activity, AMPK, SIRT1 and PGC1α proteins, and parvalbumin interneurons in the amygdala were assessed following evaluation of ASD and anxiety-like behaviors. Amygdala analysis revealed ROS accumulation and decreased MMP in autistic rats. In addition, caspase-3 activation elevated and immunoreactivity for parvalbumin interneurons decreased. These were accompanied by anxiety and autistic-like behaviors in open field test, elevated zero maze and U-Shaped 2 Choice Field maze. Also, our data showed that in the valproate group, protein levels of AMPK, SIRT1 and PGC1α reduced. Collectively, our results indicate that prenatal exposure to valproate leads to anxiety and autistic-like behaviors, partly through its targeting amygdala parvalbumin interneurons dysfunction and this might be affected by disturbed AMPK/SIRT1/PGC1α signaling pathway.

Scutellarin alleviates lipopolysaccharide-provoked septic nephrotoxicity via attenuation of inflammatory and oxidative events and mitochondrial dysfunction.

BACKGROUND: Sepsis-associated acute kidney injury (AKI) is highlighted by high incidence of mortality and morbidity. Scutellarin is a flavone extracted from certain medicinal plants with anti-inflammatory and anti-oxidative properties. This research study was done to investigate the beneficial effect of scutellarin on lipopolysaccharide (LPS) murine model of AKI. MATERIALS AND METHODS: Five groups of mice were used including control (without LPS injection), LPS group (LPS injection, 10 mg/kg), and LPS + Scutellarin25, 50, and/or 100 groups (receiving scutellarin orally at different doses of 25, 50, or 100 mg/kg before LPS injection). RESULTS: Scutellarin pretreatment effectively lowered kidney function markers (BUN, creatinine, and cystatin C), improved superoxide dismutase (SOD) besides enhancement of level, and/or gene expression for nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase 1 (HO-1) and also reduced oxidative stress factors including reactive oxygen species (ROS) and malondialdehyde (MDA). In addition, scutellarin reduced tissue level and/or gene expression of inflammatory markers comprising toll-like receptor 4 (TLR4), nuclear factor-kappaB (NF-κB), and tumor necrosis factor α (TNF-α) and properly raised anti-inflammatory factor IL-10. Moreover, scutellarin enhanced mitochondrial membrane potential (MMP) and attenuated histopathological changes in renal tissue subsequent to LPS challenge. Beneficial effects of scutellarin was associated with improvement of gene expression regarding peroxisome proliferator-activated receptor gamma (PPARγ) and its coactivator PGC-1α as specific markers of mitochondrial biogenesis. CONCLUSION: These results indicate that scutellarin could protect against LPS-provoked AKI through restraining inflammation and oxidative stress and maintenance of mitochondrial health and biogenesis which is partly mediated through its regulation of Nrf2/PPAR-γ/PGC-1α/NF-kB/TLR4.

Sinapic acid ameliorates paracetamol-induced acute liver injury through targeting oxidative stress and inflammation.

BACKGROUND: Acetaminophen (paracetamol, APAP) overdose is the principal cause of acute liver injury (ALI) that leads to liver failure typified with oxidative stress, mitochondrial and lysosomal dysfunction and with few antidotes for this condition. Therefore, more effective therapeutics are urgently required. Sinapic acid is a phenolic phytochemical with significant antioxidant, anti-inflammatory and hepatoprotective potential. RATIONALE AND PURPOSE OF THE STUDY: This study was conducted to evaluate hepatoprotective effect of this phytochemical in acetaminophen-induced model of ALI. METHODS AND RESULTS: Male C57BL/6 mice were treated p.o. with sinapic acid (10 or 50 mg/kg) 3 times at 72, 24, and 1 h before APAP (300 mg/kg; i.p.) challenge. Functional factors of liver dysfunction were determined along with hepatic assessment of oxidative stress and inflammatory indexes and histopathological analysis was also conducted. Sinapic acid (50 mg/kg) properly decreased serum levels of ALT, ALP, and AST besides reducing liver level of ROS, MDA, IL-6, TNF-α, NF-kB, and MPO and improved sirtuin 1, HO-1, Nrf2, SOD activity, and MMP with no significant effect on IL-1ß and catalase activity in addition to decreasing activity of lysosomal enzymes including cathepsin B and ß-galactosidase. Also, sinapic acid at the higher dose ameliorated liver histopathological changes due to APAP and properly reversed NF-kB and Nrf2 immunoreactivity. CONCLUSIONS: These findings show that sinapic acid pretreatment effectively protects liver against adverse and hepatotoxic effect of APAP through its antioxidant- and anti-inflammatory potential linked to NF-kB/Nrf2/HO-1 signaling and also via regulation of sirtuin 1, mitochondrial integrity, and lysosomal stabilization.

Therapeutic effect of lycopene in lipopolysaccharide nephrotoxicity through alleviation of mitochondrial dysfunction, inflammation, and oxidative stress.

BACKGROUND: Sepsis-associated acute kidney injury (AKI) accompanies a higher mortality in intensive care patients. High-dose lipopolysaccharides (LPS) as an endotoxin is usually used to model AKI in rodents. Lycopene is a fat-soluble carotenoid with proved protective effects in different condition. Rationale and purpose of the study. This research work was designed to assess the effect of lycopene in LPS murine AKI. METHODS AND RESULTS: LPS was injected (intraperitoneally) at 10 mg/kg to induce AKI and lycopene was given (orally) at 5 or 20 mg/kg. Pretreatment of LPS group with lycopene (20 mg/kg) lowered serum BUN, creatinine, and cystatin C and alleviated renal indices of oxidative stress consisting of malondialdehyde and reactive oxygen species and elevated level of catalase activity, superoxide dismutase activity, and glutathione peroxidase activity. In addition, lycopene (20 mg/kg) attenuated renal neutrophil infiltration and reduced renal inflammation, improved mitochondrial membrane potential, and increased gene expression for PGC1-α as a key regulator of mitochondrial biogenesis. In addition, lycopene appropriately reduced level and gene expression of inflammation-related transcription factors including NF-kB and TLR4 and improved level and gene expression of Nrf2 as an important transcription factor related to antioxidant system. Besides, lycopene prevented histopathological changes following LPS in periodic acid-Schiff staining. CONCLUSIONS: Collectively, this study revealed that lycopene has favorable effects by means of amelioration of mitochondrial dysfunction, oxidative stress, and inflammation and accordingly could protect against LPS-induced AKI.

Nobiletin prevents amyloid ß1-40-induced cognitive impairment via inhibition of neuroinflammation and oxidative/nitrosative stress.

Alzheimer's disease (AD) is presented as an age-related neurodegenerative disease with multiple cognitive deficits and amyloid ß (Aß) accumulation is the most important involved factor in its development. Nobiletin is a bioflavonoid isolated from citrus fruits peels with anti-inflammatory and anti-oxidative activity as well as anti-dementia property that has shown potency to ameliorate intracellular and extracellular Ab. The aim of the present study was to assess protective effect of nobiletin against Aß1-40-induced cognitive impairment as a consistent model of AD. After bilateral intrahippocampal (CA1 subfield) injection of Aß1-40, rats were treated with nobiletin (10 mg/kg/day; p.o.) from stereotaxic surgery day (day 0) till day + 7. Cognition function was evaluated in a battery of behavioral tasks at week 3 with final assessment of hippocampal oxidative stress and inflammation besides Nissl staining and 3-nitrotyrosine (3-NT) immunohistochemistry. Analysis of behavioral data showed notable and significant improvement of alternation in Y maze test, discrimination ratio in novel object recognition task, and step through latency in passive avoidance test in nobiletin-treated Aß group. Additionally, nobiletin treatment was associated with lower hippocampal levels of MDA and ROS and partial reversal of SOD activity and also improvement of Nrf2 with no significant effect on GSH and catalase. Furthermore, nobiletin attenuated hippocampal neuroinflammation in Aß group as shown by lower tissue levels of TLR4, NF-kB, and TNFa. Histochemical findings showed that nobiletin prevents CA1 neuronal loss in Nissl staining in addition to its alleviation of 3-nitrotyrosine (3-NT) immunoreactivity as a marker of nitrosative stress. Collectively, these findings indicated neuroprotective and anti-dementia potential of nobiletin that is partly attributed to its anti-oxidative, anti-nitrosative, and anti-inflammatory property associated with proper modulation of TLR4/NF-kB/Nrf2 pathways.

Fetal Hypothyroidism Impairs Aortic Vasorelaxation Responses in Adulthood: Involvement of Hydrogen Sulfide and Nitric Oxide Cross talk.

ABSTRACT: Thyroid hormones have a wide range of effects on growth, differentiation, evolution, metabolism, and physiological function of all tissues, including the vascular bed. In this study, the effect of fetal hypothyroidism on impairment of aortic vasorelaxation responses in adulthood was investigated with emphasis on possible involvement of hydrogen sulfide (H2S)/nitric oxide interaction. Two groups of female rats were selected. After mating and observation of vaginal plaque, one group received propylthiouracil (200 ppm in drinking water) until the end of pregnancy and another group had no propylthiouracil treatment during the fetal period. In adult rats, aortic relaxation responses to l-arginine and GYY4137 were assessed in the presence or absence of Nω-nitro-L-arginine methyl ester hydrochloride and dl-propargylglycine in addition to the biochemical measurement of thyroid hormones and some related factors. Obtained findings showed a lower vasorelaxation response for GYY4137 and l-arginine in the fetal hypothyroidism group, and preincubation with Nω-nitro-L-arginine methyl ester hydrochloride or dl-propargylglycine did not significantly aggravate this weakened relaxation response. In addition, aortic levels of sirtuin 3, endothelial nitric oxide synthase, cystathionine gamma-lyase, and H2S were significantly lower in the fetal hypothyroidism group. Meanwhile, no significant changes were obtained regarding serum levels of thyroid hormones including free triiodothyronine;, total triiodothyronine, free thyroxine, total thyroxine, and thyroid-stimulating hormone in adult rats. It can be concluded that hypothyroidism in the fetal period has inappropriate effects on the differentiation and development of vascular bed with subsequent functional abnormality that persists into adulthood, and part of this vascular abnormality is mediated through weakened interaction and/or cross talk between H2S and nitric oxide.

Diosgenin Attenuates Cognitive Impairment in Streptozotocin-Induced Diabetic Rats: Underlying Mechanisms.

OBJECTIVE: Prolonged diabetes mellitus causes impairments of cognition and attentional dysfunctions. Diosgenin belongs to a group of steroidal saponins with reported anti-diabetic and numerous protective properties. This research aimed to assess the effect of diosgenin on beneficially ameliorating learning and memory decline in a rat model of type 1 diabetes caused by streptozotocin (STZ) and to explore its modes of action including involvement in oxidative stress and inflammation. METHODS: Rats were assigned to one of four experimental groups, comprising control, control under treatment with diosgenin, diabetic, and diabetic under treatment with diosgenin. Diosgenin was given daily p.o. (40 mg/kg) for 5 weeks. RESULTS: The administration of diosgenin to the diabetic group reduced the deficits of functional performance in behavioral tests, consisting of Y-maze, passive avoidance, radial arm maze, and novel object discrimination tasks (recognitive). Furthermore, diosgenin treatment attenuated hippocampal acetylcholinesterase activity and malon-dialdehyde, along with improvement of antioxidants such as superoxide dismutase and glutathione. Meanwhile, the hippocampal levels of inflammatory indicators, namely interleukin 6, nuclear factor-κB, toll-like receptor 4, tumor necrosis factor α, and astrocyte-specific biomarker glial fibrillary acidic protein, were lower and, on the other hand, tissue levels of nuclear factor (erythroid-derived 2)-related factor 2 were elevated upon diosgenin administration. Besides, the mushroom-like spines of the pyramidal neurons of the hippocampal CA1 area decreased in the diabetic group, and this was alleviated following diosgenin medication. CONCLUSIONS: Taken together, diosgenin is capable of ameliorating cognitive deficits in STZ-diabetic animals, partly due to its amelioration of oxidative stress, inflammation, astrogliosis, and possibly improvement of cholinergic function in addition to its neuroprotective potential.

Dual Profile of Environmental Enrichment and Autistic-Like Behaviors in the Maternal Separated Model in Rats.

BACKGROUND: Environmental Enrichment (EE) has been suggested as a possible therapeutic intervention for neurodevelopmental disorders such as autism. Although the benefits of this therapeutic method have been reported in some animal models and human studies, the unknown pathophysiology of autism as well as number of conflicting results, urge for further examination of the therapeutic potential of EE in autism. Therefore, the aim of this study was to examine the effects of environmental enrichment on autism-related behaviors which were induced in the maternal separation (MS) animal model. MATERIAL AND METHODS: Maternally separated (post-natal day (PND) 1-14, 3h/day) and control male rats were at weaning (PND21) age equally divided into rats housed in enriched environment and normal environment. At adolescence (PND42-50), the four groups were behaviorally tested for direct social interaction, sociability, repetitive behaviors, anxiety behavior, and locomotion. Following completion of the behavioral tests, the blood and brain tissue samples were harvested in order to assess plasma level of brain derived neurotrophic factor (BDNF) and structural plasticity of brain using ELISA and stereological methods respectively. RESULTS: We found that environmental enrichment reduced repetitive behaviors but failed to improve the impaired sociability and anxiety behaviors which were induced by maternal separation. Indeed, EE exacerbated anxiety and social behaviors deficits in association with increased plasma BDNF level, larger volume of the hippocampus and infra-limbic region and higher number of neurons in the infra-limbic area (p < 0.05). Conclusion: We conclude that environmental enrichment has a significant improvement effect on the repetitive behavior as one of the core autistic-like behaviors induced by maternal separation but has negative effect on the anxiety and social behaviors which might have been modulated by BDNF.

Protective effect of diosgenin on LPS/D-Gal-induced acute liver failure in C57BL/6 mice.

Acute liver failure (ALF) is a deadly clinical syndrome, which leads to a rapid loss of normal liver function. Diosgenin is a natural steroidal sapogenin found in various plant families. Various studies have shown that diosgenin have therapeutic or preventive effect in various diseases such as cancer, cardiovascular disorders, type 2 diabetes, and neurodegenerative disorders. In this study, we evaluated effects of diosgenin on mice model of ALF. Animal model of ALF was induced by intraperitoneal injection of lipopolysaccharide (LPS)/d-galactosamine (D-Gal). The male C57BL/6 mice were randomly divided into 3 groups: control group, LPS/D-Gal group, and LPS/D-Gal + diosgenin group (50 mg/kg). Mice in the LPS/D-Gal group received a combination of LPS (50 µg/kg) and D-Gal (400 mg/kg) intraperitoneally. LPS/D-Gal + diosgenin group received diosgenin twice orally 24 h and 1 h before receiving LPS/D-Gal. Markers of liver injury including ALT, AST and ALP were measured in blood samples in addition to determination of oxidative stress and inflammatory markers including MDA, nitrite, ROS, catalase, SOD, Nrf2, IL-1ß, IL-6, TLR4, TNF-α and NF-κB in hepatic tissue. Administration of diosgenin could greatly reduce serum levels of ALT, AST, and ALP. Besides, hepatic levels of MDA, ROS, IL-1ß, IL-6, TLR4, TNF-α, and NF-κB significantly decreased and SOD activity and Nrf2 level increased in comparison with the LPS/D-Gal group. In addition, myeloperoxidase activity as a marker of neutrophil infiltration decreased following diosgenin administration. In summary, diosgenin led to reduction of liver injury indices and oxidative stress and inflammatory events and diosgenin has probably hepatoprotecive effects in ALF.

Netrin-1 protects the SH-SY5Y cells against amyloid beta neurotoxicity through NF-κB/Nrf2 dependent mechanism.

Many evidence confirms that amyloid beta 1-42 fragment (Aß1-42) causes neuroinflammation, oxidative stress, and cell death, which are related to progressive memory loss, cognitive impairments and mental disorders that will lead to Alzheimer's disease (AD) progression. Netrin-1, as a member of the laminins, has been proved to inhibit apoptosis and inflammation outside of nervous system, in addition to having a vital role in morphogenesis and neurogenesis of neural system. This study was designed to assess the protective effects of netrin-1 in SH-SY5Y human neuroblastoma cell line exposed to Aß1-42 and to explore some mechanisms that underlie netrin-1 effects. Cultured SH-SY5Y neuroblast-like cells were treated with netrin-1 prior to Aß1-42 exposure and the effects were assessed by MTT and ELISA assay kits. Netrin- 1 pretreatment of Aß1-42-exposed SH-SY5Y human neuroblastoma cells attenuated Aß1-42 induced toxic effects, increased cell viability and partially restored levels of 3 inflammatory and oxidative stress biomarkers including: nuclear factor erythroid 2-like 2 (Nrf2), tumor necrosis factor alpha (TNFα) and nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB). Based on the findings of this study, netrin-1 represents a promising therapeutic bio agent to abrogate cellular inflammation and reactive oxygen species (ROS) activation induced by Aß1-42 in the SH-SY5Y cell model of AD.

S-allyl cysteine, an active ingredient of garlic, attenuates acute liver dysfunction induced by lipopolysaccharide/ d-galactosamine in mouse: Underlying mechanisms.

In the present study, beneficial effect of S-allyl cysteine (SAC) was evaluated in the lipopolysaccharide/d-galactosamine (LPS/d-Gal) model of acute liver injury (ALI). To mimic ALI, LPS and d-Gal (50 µg/kg and 400 mg/kg, respectively) were intraperitoneally administered and animals received SAC per os (25 or 100 mg/kg/d) for 3 days till 1 hour before LPS/d-Gal injection. Pretreatment of LPS/d-Gal group with SAC-lowered activities of alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase and partially reversed inappropriate alterations of hepatic oxidative stress- and inflammation-related biomarkers including liver reactive oxygen species, malondialdehyde, and hepatic activity of the defensive enzyme superoxide dismutase, ferric reducing antioxidant power (FRAP), toll-like receptor-4 (TLR4), cyclooxygenase 2, NLR family pyrin domain containing 3 (NLRP3), caspase 1, nuclear factor κB (NF-κB), interleukin 1ß (IL-1ß), IL-6, tumor necrosis factor-α, and myeloperoxidase activity. Additionally, SAC was capable to ameliorate apoptotic biomarkers including caspase 3 and DNA fragmentation. In summary, SAC can protect liver against LPS/d-Gal by attenuation of neutrophil infiltration, oxidative stress, inflammation, apoptosis, and pyroptosis which is partly linked to its suppression of TLR4/NF-κB/NLRP3 signaling.

The effects simultaneous inhibition of dipeptidyl peptidase-4 and P2X7 purinoceptors in an in vivo Parkinson's disease model.

Loss of dopaminergic neurons following Parkinson's disease (PD) diminishes quality of life in patients. The present study was carried out to investigate the protective effects of simultaneous inhibition of dipeptidyl peptidase-4 (DPP-4) and P2X7 purinoceptors in a PD model and explore possible mechanisms. The 6-hydroxydopamine (6-OHDA) was used as a tool to establish PD model in male Wister rats. The expressions of SIRT1, SIRT3, mTOR, PGC-1α, PTEN, P53 and DNA fragmentation were evaluated by ELISA assay. Behavioral impairments were determined using apomorphine-induced rotational and narrow beam tests. Dopamine synthesis and TH-positive neurons were detected by tyrosine hydroxylase (TH) immunohistochemistry. Neuronal density was determined by Nissl staining. OHDA-lesioned rats exhibited behavioral impairments that reversed by BBG, lin and lin + BBG. We found significant reduced levels of SIRT1, SIRT3, PGC-1α and mTOR in both mid brain and striatum from OHDA-lesioned rats that reversed by BBG, lin and lin + BBG. Likewise, significant increased levels of PTEN and P53 were found in both mid brain and striatum from OHDA-lesioned rats that was reversed by BBG, lin and lin + BBG. TH-positive neurons and neuronal density were markedly reduced OHDA-lesioned rats that reversed by BBG, lin and lin + BBG. Collectively, our results showed protective effects of simultaneous inhibition of DPP-4 and P2X7 purinoceptors in a rat model of PD can be linked to targeting SIRT1/SIRT3, PTEN-mTOR pathways. Moreover, our findings demonstrated that simultaneous inhibition of DPP-4 and P2X7 purinoceptors might have stronger effect on mitochondrial biogenesis compared to only one.

Assessment of the protective effect of KN-93 drug in systemic epilepsy disorders induced by pilocarpine in male rat.

BACKGROUND AND AIMS: Epileptic seizures occur as a consequence of a sudden imbalance between the stimuli and inhibitors within the network of cortical neurons in favor of the stimulus. One of the drugs that induce epilepsy is pilocarpine. Systemic injection of pilocarpine affects on muscarinic receptors. Increasing evidence has addressed the implication of KN-93 by blocking Ca2+ /calmodulin-dependent protein kinase II (CaMKII), suppressing oxidative stress and inflammation, and also reducing neuron decay. So, we aimed to evaluate the potential preventive effects of KN-93 in systemic epilepsy disorders induced by pilocarpine. MATERIALS AND METHODS: In this animal study, male rats were divided into five groups including treatment group (KN-93 with the dose of 5 mM/10 µL dimethyl sulfoxide (DMSO) before inducing epilepsy by 380 mg/kg pilocarpine) KN-93 group (received 5 mM KN-93), control group, epilepsy group (received 380 mg/kg pilocarpine Intraperitoneal), and sham group (received 10 µL DMSO). Oxidative stress was assessed by measuring its indicators including the concentration of malondialdehyde (MDA), nitrite, glutathione (GSH), as well as the antioxidant activity of catalase. In addition, serum levels of proinflammatory mediators including tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) were determined. RESULTS: Pretreatment with KN-93 significantly reduced oxidative stress index by reducing the concentration of MDA, nitrite, and increasing the level of GSH. In addition, low concentrations of TNF-α and IL-1ß were observed in hippocampus supernatant of KN-93 pretreated rats in comparison with the pilocarpine groups. Moreover, administration of KN-93 improved neuronal density and attenuated the seizure activity and behavior. CONCLUSIONS: Overall, our findings suggest that KN-93 can effectively suppress oxidative stress and inflammation. Furthermore, KN-93 is able to attenuate seizure behaviors by preventing its effects on neuron loss, so, it is valuable for the treatment of epileptic seizures.

Key mechanisms underlying netrin-1 prevention of impaired spatial and object memory in Aß1-42 CA1-injected rats.

Alzheimer's disease (AD) is a neurodegenerative disorder with an incompletely defined aetiology that is associated with memory and cognitive impairment. Currently available therapeutics only provide temporary assistance with symptoms. In spite of plentiful research in the field and the generation of thousands of studies, much is still to be clarified on precise mechanisms of pathobiology, prevention modalities, disease course and cure. Netrin-1, a laminin family protein, is said to have anti-inflammatory and anti-apoptotic effects and has a key role in neurogenesis and morphogenesis of neural structures. Accordingly, this study was designed to investigate protective effects of bilateral intrahippocampal fissure microinjections of netrin-1 on memory impairment in rat model of AD. Concomitant administration of netrin-1 with amyloid beta 1-42 (Aß1-42 ) improved cognitive dysfunction in novel object recognition task (NOR), ameliorated impaired spatial memory in Morris water maze (MWM) setting, increased neuronal density and reduced amyloid aggregation in rat AD model. Netrin-1 was also seen to prevent Aß1-42 -induced caspase-3, caspase-7 and NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation. Therefore, based on the data reported here, netrin-1 may be a promising biologic therapeutic that addresses the memory and neuronal loss associated with AD.

Huperzine A ameliorates cognitive dysfunction and neuroinflammation in kainic acid-induced epileptic rats by antioxidant activity and NLRP3/caspase-1 pathway inhibition.

Temporal lobe epilepsy (TLE) is one of the most prevalent types of epilepsy in human. Huperzine A (Hup-A) has been reported to possess antioxidative and anti-inflammatory properties; however, its role in TLE induced by kainic acid has not been determined. The current study investigated the protective effects of Hup-A (0.1 mg/kg) in kainic acid-induced model of TLE in the rat. In the current study, it was found that Hup-A significantly prevented the seizure intensity and learning and memory deterioration which was assessed by Morris water maze (MWM) and novel object recognition task (NOR). Additionally, Hup-A inhibited oxidative stress, inflammation, and acetylcholinesterase activity (AChE). In addition, catalase and superoxide dismutase (SOD) activities increased after Hup-A treatment, while malondialdehyde (MDA) and nitrite levels significantly reduced. Regarding inflammation, this drug decreased kainic acid-induced NLRP3 expression in microglial cells and caspase-1 activity in hippocampal tissue, possibly through diminishing oxidative stress. Taken together, our data showed that Hup-A could be a potential protective substance to ameliorate seizure severity and some memory deficits related to epilepsy via attenuating neuroinflammation and protection of neurons.

Safranal, an active ingredient of saffron, attenuates cognitive deficits in amyloid ß-induced rat model of Alzheimer's disease: underlying mechanisms.

Alzheimer's disease (AD) is the most prevalent neurodegenerative amyloid disorder with progressive deterioration of cognitive and memory skills. Despite many efforts, no decisive therapy yet exists for AD. Safranal is the active constituent of saffron essential oil with antioxidant, anti-inflammatory, and anti-apoptotic properties. In this study, the possible beneficial effect of safranal on cognitive deficits was evaluated in a rat model of AD induced by intrahippocampal amyloid beta (Aß1-40). Safranal was daily given p.o. (0.025, 0.1, and 0.2 ml/kg) post-surgery for 1 week and finally learning and memory were evaluated in addition to assessment of the involvement of oxidative stress, inflammation, and apoptosis. Findings showed that safranal treatment of amyloid ß-microinjected rats dose-dependently improved cognition in Y-maze, novel-object discrimination, passive avoidance, and 8-arm radial arm maze tasks. Besides, safranal attenuated hippocampal level of malondialdehyde (MDA), reactive oxygen species (ROS), protein carbonyl, interleukin 1ß (IL-1ß), interleukin 6 (IL-6), tumor necrosis factor α (TNFα), nuclear factor-kappa B (NF-kB), apoptotic biomarkers including caspase 3 and DNA fragmentation, glial fibrillary acidic protein (GFAP), myeloperoxidase (MPO), and acetylcholinesterase (AChE) activity and improved superoxide dismutase (SOD) activity and mitochondrial membrane potential (MMP) with no significant effect on nitrite, catalase activity, and glutathione (GSH). Furthermore, safranal prevented CA1 neuronal loss due to amyloid ß1-40. In summary, safranal treatment of intrahippocampal amyloid beta1-40-microinjected rats could prevent learning and memory decline via neuronal protection and at a molecular level through amelioration of apoptosis, oxidative stress, inflammation, cholinesterase activity, neutrophil infiltration, and also by preservation of mitochondrial integrity.

Trigonelline protects hippocampus against intracerebral Aß(1-40) as a model of Alzheimer's disease in the rat: insights into underlying mechanisms.

Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most common phenotype of dementia. Trigonelline is an alkaloid found in medicinal plants such as fenugreek seeds and coffee beans with neuroprotective potential and according to existing evidences, a favorable agent for treatment of neurodegenerative disorders. In this study, the possible protective effect of trigonelline against intracerebral Aß(1-40) as a model of AD in the rat was investigated. For induction of AD, aggregated A(1-40) (10 µg/2 휇l for each side) was bilaterally microinjected into the hippocampal CA1 area. Trigonelline was administered p.o. at a dose of 100 mg/kg. The results showed that trigonelline pretreatment of Aß-microinjected rats significantly improves spatial recognition memory in Y maze and performance in novel object recognition (NOR) task, mitigates hippocampal malondialdehyde (MDA), protein carbonyl, lactate dehydrogenase (LDH), and improves mitochondrial membrane potential (MMP), glutathione (GSH), and superoxide dismutase (SOD) with no significant change of catalase activity, nitrite level, caspase 3 activity, and DNA fragmentation. Additionally, trigonelline ameliorated hippocampal levels of glial fibrillary acidic protein (GFAP), S100b, cyclooxygenase 2 (Cox2), tumor necrosis factor α (TNFα), and interleukin 6 (IL-6) with no significant alteration of inducible nitric oxide synthase (iNOS). In addition, trigonelline pretreatment prevented loss of hippocampal CA1 neurons in Aß-microinjected group. Therefore, our results suggest that trigonelline pretreatment in Aß model of AD could improve cognition and is capable to alleviate neuronal loss through suppressing oxidative stress, astrocyte activity, and inflammation and also through preservation of mitochondrial integrity.

Troxerutin exerts neuroprotection against lipopolysaccharide (LPS) induced oxidative stress and neuroinflammation through targeting SIRT1/SIRT3 signaling pathway.

This study was conducted to clarify the potential mechanisms of Troxerutin neuroprotection against Lipopolysaccharide (LPS) induced oxidative stress and neuroinflammation through targeting the SIRT1/SIRT3 signaling pathway. To establish a model, a single dose of LPS (500µg/kg body weight) was injected to male Wistar rats intraperitoneally. Troxerutin (100 mg/kg body weight) was injected intraperitoneally for 5 days after induction of the model. Cognitive and behavioral evaluations were performed using Y-maze, single-trial passive avoidance, and novel object recognition tests. The expression of inflammatory mediators, SIRT1/SIRT3, and P53 was measured using the ELISA assay. Likewise, the expression levels of SIRT1/SIRT3 and NF-κB were determined using Western blot assay. Brain acetyl-cholinesterase activity was determined by utilizing the method of Ellman. Reactive oxygen species (ROS) was detected using Fluorescent probe 2, 7-dichlorofluorescein diacetate (DCFH-DA). Furthermore, malondialdehyde (MDA) levels were determined. A single intraperitoneal injection of LPS was led to ROS production, acute neuroinflammation, apoptotic cell death, and inactivation of the SIRT1/SIRT3 signaling pathway. Likewise, ELISA assay demonstrated that post-treatment with Troxerutin considerably suppressed LPS-induced acute neuroinflammation, oxidative stress, apoptosis and subsequently memory impairments by targeting SIRT1/SIRT3 signaling pathway. Western blot assay confirmed ELISA results about SIRT1/SIRT3 and NF-κB proteins. These results suggest that Troxerutin can be a suitable candidate to treat neuroinflammation caused by neurodegenerative disorders.

Berberine ameliorates lipopolysaccharide-induced learning and memory deficit in the rat: insights into underlying molecular mechanisms.

Systemic lipopolysaccharide (LPS) triggers neuroinflammation with consequent development of behavioral and cognitive deficits. Neuroinflammation plays a crucial role in the pathogenesis of neurodegenerative disorders including Alzheimer's disease (AD). Berberine is an isoquinoline alkaloid in Berberis genus with antioxidant and anti-inflammatory property and protective effects in neurodegenerative disorders. In this research, beneficial effect of this alkaloid against LPS-induced cognitive decline was assessed in the adult male rats. LPS was intraperitoneally administered at a dose of 1 mg/kg to induce neuroinflammation and berberine was given via gavage at doses of 10 or 50 mg/kg, one h after LPS, for 7 days. Treatment of LPS group with berberine at a dose of 50 mg/kg (but not at a dose of 10 mg/kg) improved spatial recognition memory in Y maze, performance in novel object recognition task (NORT), and prevented learning and memory dysfunction in passive avoidance tasks. Furthermore, berberine lowered hippocampal activity of acetylcholinesterase (AChE), malondialdehyde (MDA), protein carbonyl, activity of caspase 3, and DNA fragmentation and improved antioxidant capacity through enhancing glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase, and glutathione (GSH). Besides, berberine attenuated inflammation-related indices, as was evident by lower levels of nuclear factor-kappa B (NF-κB), toll-like receptor 4 (TLR4), tumor necrosis factor α (TNFα), and interleukin 6 (IL-6). Berberine also appropriately restored hippocampal 3-nitrotyrosine (3-NT), cyclooxygenase 2 (Cox 2), glial fibrillary acidic protein (GFAP), sirtuin 1, and mitogen-activated protein kinase (p38 MAPK) with no significant alteration of brain-derived neurotrophic factor (BDNF). In summary, berberine could partially ameliorate LPS-induced cognitive deficits via partial suppression of apoptotic cascade, neuroinflammation, oxido-nitrosative stress, AChE, MAPK, and restoration of sirtuin 1.