Effects of isosakuranetin on cerebral infarction and blood brain barrier damage from cerebral ischemia/reperfusion injury in a rat model.

This study investigated the effects of isosakuranetin (5,7-dihydroxy-4'-methoxyflavanone) on cerebral infarction and blood brain barrier (BBB) damage in cerebral ischemia and reperfusion (I/R) in a rat model. The right middle cerebral artery was occluded for 2 h followed by reperfusion. The experimental rats were divided into five groups: a sham, or control group; vehicle group; and 5 mg/kg, 10 mg/kg, and 20 mg/kg bodyweight isosakuranetin-treated I/R groups. After 24 h of reperfusion, the rats were tested using a six-point neurological function score. The percentage of cerebral infarction was evaluated using 2,3,5-triphenyltetrazolium chloride (TTC) staining. BBB leakage was determined by Evan Blue injection assay and brain morphology changes were observed under light microscopy following staining with hematoxylin and eosin (H&E). The results of neurological function score revealed that isosakuranetin reduced the severity of neurological damage. A dose of 10 and 20 mg/kg bodyweight of isosakuranetin significantly decreased the infarct volume. All three doses of isosakuranetin significantly decreased Evan Blue leakage. The penumbra area of the I/R brains revealed the characteristics of apoptotic cell death. Therefore, isosakuranetin-treated I/R attenuated the brain damage from cerebral I/R injury and further investigation of the mechanisms warrant further investigation to assist in the development of protective strategies against cerebral I/R injury in clinical trials.Communicated by Ramaswamy H. Sarma.

Hexahydrocurcumin attenuated demyelination and improved cognitive impairment in chronic cerebral hypoperfusion rats.

Age-related white matter lesions (WML) frequently present vascular problems by decreasing cerebral blood supply, resulting in the condition known as chronic cerebral hypoperfusion (CCH). This study aimed to investigate the effect of hexahydrocurcumin (HHC) on the processes of demyelination and remyelination induced by the model of the Bilateral Common Carotid Artery Occlusion (BCCAO) for 29 days to mimic the CCH condition. The pathological appearance of myelin integrity was significantly altered by CCH, as evidenced by Transmission Electron Microscopy (TEM) and Luxol Fast Blue (LFB) staining. In addition, CCH activated A1-astrocytes and reactive-microglia by increasing the expression of Glial fibrillary acidic protein (GFAP), complement 3 (C3d) and pro-inflammatory cytokines. However, S100a10 expression, a marker of neuroprotective astrocytes, was suppressed, as were regenerative factors including (IGF-1) and Transglutaminase 2 (TGM2). Therefore, the maturation step was obstructed as shown by decreases in the levels of myelin basic protein (MBP) and the proteins related with lipid synthesis. Cognitive function was therefore impaired in the CCH model, as evidenced by the Morris water maze test. By contrast, HHC treatment significantly improved myelin integrity, and inhibited A1-astrocytes and reactive-microglial activity. Consequently, pro-inflammatory cytokines and A1-astrocytes were attenuated, and regenerative factors increased assisting myelin maturation and hence improving cognitive performance. In conclusion, HHC improves cognitive function and also the integrity of white matter in CCH rats by reducing demyelination, and pro-inflammatory cytokine production and promoting the process of remyelination.

Hexahydrocurcumin Attenuates Neuronal Injury and Modulates Synaptic Plasticity in Chronic Cerebral Hypoperfusion in Rats.

Dementia is the most common age-related problem due predominantly to Alzheimer's disease (AD) and vascular dementia (VaD). It has been shown that these contributors are associated with a high amount of oxidative stress that leads to changes in neurological function and cognitive impairment. The aim of study was to explore the mechanism by which hexahydrocurcumin (HHC) attenuates oxidative stress, amyloidogenesis, phosphorylated Tau (pTau) expression, neuron synaptic function, and cognitive impairment and also the potential mechanisms involved in induced permanent occlusion of bilateral common carotid arteries occlusion (BCCAO) or 2-vessel occlusion (2VO) in rats. After surgery, rats were treated with HHC (40 mg/kg) or piracetam (600 mg/kg) by oral gavage daily for 4 weeks. The results showed that HHC or piracetam attenuated oxidative stress by promoting nuclear factor erythroid 2-related factor 2 (Nrf2) activity, and alleviated expression of synaptic proteins (pre- and post-synaptic proteins) mediated by the Wingless/Integrated (Wnt)/ß-catenin signaling pathway. Moreover, HHC or piracetam also improved synaptic plasticity via the brain-derived neurotrophic factor (BDNF)/Tyrosine receptor kinase B (TrkB)/cAMP responsive element binding protein (CREB) signaling pathway. In addition, HHC reduced amyloid beta (Aß) production and pTau expression and improved memory impairment as evidenced by the Morris water maze. In conclusion, HHC exerted remarkable improvement in cognitive function in the 2VO rats possibly via the attenuation of oxidative stress, improvement in synaptic function, attenuation of amyloidogenesis, pTau, and neuronal injury, thereby improving cognitive performance.

Pelargonic acid vanillylamide alleviates hepatic autophagy and ER stress in hepatic steatosis model.

Pelargonic acid vanillylamide (PAVA) has been shown to reduce hepatic lipid accumulation in an obese rat model, however the underlying mechanism responsible for regulating lipid metabolism remains unclear. This study investigated the molecular mechanisms invoked by PAVA in regulating lipogenesis, autophagy, and endoplasmic reticulum (ER) stress in obese rats. Male Sprague-Dawley rats were fed on a diet consisting of 65.26% fat (16 weeks) and HepG2 cells were incubated with 200 µM oleic acid (OA) plus 100 µM palmitic acid (PA) for 48 h. These treatments resulted in a steatosis model. PAVA was shown to reduce fat deposition in hepatocytes in HepG2 by reducing lipotoxicity, the triglyceride content, the expression of sterol regulatory element binding protein 1c (SREBP-1c) and fatty acid synthase (FASN). PAVA also significantly reduced the calcium level and the expression of calpain 2 and upregulated the expression of Atg7 in comparison to the HFD group. In addition, PAVA was shown to significantly decrease the expression of autophagy pathway-related proteins including LC3 and p62. Treatment with PAVA (1 mg/day) reduced the expressions of ER stress markers Bip, ATF6 (p50), p-IRE1/IRE1, p-eIF2α/eIF2α, pJNK, CHOP and cleaved CASP12. In conclusion, PAVA ameliorated obesity induced hepatic steatosis by attenuating defective autophagy and ER stress pathways.

Hexahydrocurcumin mitigates angiotensin II-induced proliferation, migration, and inflammation in vascular smooth muscle cells.

The proliferation and migration of vascular smooth muscle cells (VSMCs) play vital roles in the pathogenesis of atherosclerosis and hypertension. It has been proposed and verified that hexahydrocurcumin (HHC), a metabolite form of curcumin, has cardiovascular protective effects. This study examined the effect of HHC on angiotensin II (Ang II)-induced proliferation, migration, and inflammation in rat aortic VSMCs and explored the molecular mechanisms related to the processes. The results showed that HHC significantly suppressed Ang II-induced proliferation, migration, and inflammation in VSMCs. HHC inhibited Ang II-induction of the increase in cyclin D1 and decrease in p21 expression in VSMCs. Moreover, HHC attenuated the generation of reactive oxygen species (ROS), and the expression of nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and matrix metalloproteinases-9 (MMP9) in Ang II-induced VSMCs. The proliferation, migration, inflammation, and ROS production were also inhibited by GKT137831 (NADPH oxidase, NOX1/4 inhibitor) and the combination of HHC and GKT137831. In addition, HHC restored the Ang-II inhibited expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) and peroxisome proliferator activated receptor-γ coactivator-1α (PGC-1α). These findings indicate that HHC may play a protective role in Ang II-promoted proliferation, migration, and inflammation by suppressing NADPH oxidase mediated ROS generation and elevating PPAR-γ and PGC-1α expression. See also Figure 1(Fig. 1).

Melatonin modulates the aggravation of pyroptosis, necroptosis, and neuroinflammation following cerebral ischemia and reperfusion injury in obese rats.

Obesity is well-established as a common comorbidity in ischemic stroke. The increasing evidence has revealed that it also associates with the exacerbation of brain pathologies, resulting in increasingly severe neurological outcomes following cerebral ischemia and reperfusion (I/R) damage. Mechanistically, pyroptosis and necroptosis are novel forms of regulated death that relate to the propagation of inflammatory signals in case of cerebral I/R. Previous studies noted that pyroptotic and necroptotic signaling were exacerbated in I/R brain of obese animals and led to the promotion of brain tissue injury. This study aimed to investigate the roles of melatonin on pyroptosis, necroptosis, and pro-inflammatory pathways occurring in the I/R brain of obese rats. Male Wistar rats were given a high-fat diet for 16 weeks to induce the obese condition, and then were divided into 4 groups: Sham-operated, I/R treated with vehicle, I/R treated with melatonin (10 mg/kg), and I/R treated with glycyrrhizic acid (10 mg/kg). All drugs were administered via intraperitoneal injection at the onset of reperfusion. The development of neurological deficits, cerebral infarction, histological changes, neuronal death, and glial cell hyperactivation were investigated. This study revealed that melatonin effectively improved these detrimental parameters. Furthermore, the processes of pyroptosis, necroptosis, and inflammation were all diminished by melatonin treatment. A summary of the findings is that melatonin effectively reduces ischemic brain pathology and thereby improves post-stroke outcomes in obese rats by modulating pyroptosis, necroptosis, and inflammation.

Melatonin suppresses inflammation and blood‒brain barrier disruption in rats with vascular dementia possibly by activating the SIRT1/PGC-1α/PPARγ signaling pathway.

Chronic cerebral hypoxia (CCH) is caused by a reduction in cerebral blood flow, and cognitive impairment has been the predominant feature that occurs after CCH. Recent reports have revealed that melatonin is proficient in neurodegenerative diseases. However, the molecular mechanism by which melatonin affects CCH remains uncertain. In this study, we aimed to explore the role and underlying mechanism of melatonin in inflammation and blood‒brain barrier conditions in rats with CCH. Male Wistar rats were subjected to permanent bilateral common carotid artery occlusion (BCCAO) to establish the VAD model. Rats were randomly divided into four groups: Sham, BCCAO, BCCAO treated with melatonin (10 mg/kg), and BCCAO treated with resveratrol (20 mg/kg). All drugs were administered once daily for 4 weeks. Our results showed that melatonin attenuated cognitive impairment, as demonstrated by the Morris water maze tests. Furthermore, melatonin reduced the activation of inflammation by attenuating the phosphorylated nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitor alpha (pIκBα), causing the suppression of proteins related to inflammation and inflammasome formation. Moreover, immunohistochemistry revealed that melatonin reduced glial cell activation and proliferation, which were accompanied by Western blotting results. Additionally, melatonin also promoted the expression of sirtuin-1 (SIRT1), peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1α), and peroxisome proliferator-activated receptor-gamma (PPARγ), causing attenuated blood‒brain barrier (BBB) disruption by increasing tight junction proteins. Taken together, our results prove that melatonin treatment modulated inflammation and BBB disruption and improved cognitive function in VaD rats, partly by activating the SIRT1/PGC-1α/PPARγ signaling pathway.

The potential effects of festidinol treatment against the NLRP3 inflammasome and pyroptosis in D-galactose and aluminum chloride-induced Alzheimer's-like pathology in mouse brain.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that causes cognitive and memory decline. Neuroinflammation is currently considered as being an important pathology in AD. NLRP3, the nucleotide-binding and oligomerization (NOD) domain-like receptor (NLR) family pyrin domain (PYD)-containing 3 (NLRP3) inflammasome is a critical component of the innate immune response, which plays a key role in the development and progression of AD. Therefore, the NLRP3 inflammasome is one of the target treatments for AD. This study aimed to investigate the effect of festidinol, a flavanol isolated from Dracaena conferta, against NLRP3 inflammasome and blood-brain barrier damage in D-galactose and aluminum chloride-induced mice. The induced mice received D-galactose (150 mg/kg) and aluminum chloride (10 mg/kg) intraperitoneally for 90 days to generate cognitive impairment. Festidinol (30 mg/kg) and donepezil (5 mg/kg) were given by oral gavage for 90 days along with the induction. Then, learning and memory behavior, and molecular and morphological changes in the brain, which related to NLRP3 inflammasome, pyroptosis and the blood-brain barrier were measured. The results indicated that festidinol markedly decreased the escape latency and increased the time in the target quadrant in the Morris water maze test. Furthermore, festidinol significantly decreased the ionized calcium-binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) expression. Festidinol also markedly decreased the NLRP3 inflammasome pathway, interleukin 1 beta (IL-1ß), gasdermin-D, N-terminal (GSDMD-N) and caspase-3. Pertinent to the blood-brain barrier, festidinol only decreased tumor necrosis factor-α and matrix metallopeptidase-9, but did not restore the tight junction components. In conclusion, festidinol can restore learning and memory and provide a protective effect against the NLRP3 inflammasome and pyroptosis.

The capsaicinoid nonivamide suppresses the inflammatory response and attenuates the progression of steatosis in a NAFLD-rat model.

Nonalcoholic fatty liver disease (NAFLD) is relatively associated with comorbidities in obesity and metabolic inflammation. Low-grade inflammation following the high-fat diet (HFD)-induced NAFLD can promote the development of nonalcoholic steatohepatitis (NASH) through particularly liver-resident immune cell recruitment and hepatic nuclear factor kappa B (NF-κB) pathway. Therefore, inflammatory intervention may contribute to NASH reduction. Pelargonic acid vanillylamide (PAVA) or nonivamide is one of the pungent capsaicinoids of Capsicum species and has been found in chili peppers. Our previous study demonstrated that PAVA improved hepatic function, decreased oxidative stress and reduced apoptotic cell death but the insight role of PAVA on NAFLD is still unclear. Thus, this study aimed to investigate the underlying anti-inflammatory mechanism of PAVA in an NAFLD-rat model. Male Sprague Dawley rats were fed with normal diet or HFD for 16 weeks. Then high-fat rats were given vehicle or PAVA (1 mg/kg/day) for another 4 weeks. We found that PAVA alleviated hepatic inflammation associated with the reducing toll-like receptor 4/NF-κB pathway, showing significantly lower recruitment of cluster of differentiation 44. PAVA also maintained activity of insulin signaling pathway, and attenuated NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome formation. NAFLD progresses to NASH through transforming growth factor (TGF-ß1), and also recovery to simple stage followed by PAVA suppresses pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-1ß, interleukin-6, and Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway. Therefore, our findings suggest that PAVA provides a novel therapeutic approach for NAFLD and slows the progression to NASH.

Chronic high-fat diet consumption exacerbates pyroptosis- and necroptosis-mediated HMGB1 signaling in the brain after ischemia and reperfusion injury

Obesity is categorized as a common comorbidity found in people who experience an ischemic stroke. However, the mechanisms to explain this correlation have still not been elucidated fully. Pyroptosis and necroptosis are novel forms of programmed cell death that occur upon intracellular danger signals. The major feature of pyroptosis and necroptosis is damage to the lipid membrane, which consequently results in lytic cell death and allows the release of high mobility group box protein 1 (HMGB1) into the extracellular space. We aimed to investigate the influences of high-fat diet (HFD) consumption on cerebral ischemia and reperfusion (I/R) injury and hypothesized that HFD consumption exacerbated the activation of pyroptosis, necroptosis, and HMGB1 signaling pathways. All rats received normal diet (ND) or HFD for 16 weeks. Subsequently, both groups were divided into either a sham- or an I/R-operated group. Twenty-four hours after the surgery, all rats were evaluated for neurological deficits and then sacrificed. After I/R injury, there were more severe functional deficits and larger brain infarcts in the HFD compared with the ND group. The histological observation revealed an increase in tissue abnormalities in the HFD group, consistent with the massive reduction of intact neurons along the peri-infarct region. Furthermore, cerebral I/R injury dramatically activated the pyroptotic, necroptotic, and HMGB1 signaling pathways in HFD-fed rats compared with ND-fed rats. These findings suggest that chronic HFD consumption worsens ischemic brain pathology and leads to poor post-stroke outcomes by exacerbating pyroptotic and necroptotic cell death. (AU)

Protective Effect of Neferine in Permanent Cerebral Ischemic Rats via Anti-Oxidative and Anti-Apoptotic Mechanisms.

Permanent cerebral ischemia is a consequence of prolonged cerebral artery occlusion that results in severe brain damage. Neurotoxicity occurring after ischemia can induce brain tissue damage by destroying cell organelles and their function. Neferine is a natural compound isolated from the seed embryos of the lotus plant and has broad pharmacological effects, including blockading of the calcium channels, anti-oxidative stress, and anti-apoptosis. This study investigated the ability of neferine to reduce brain injury after permanent cerebral occlusion. Permanent cerebral ischemia in rats was induced by instigation of occlusion of the middle cerebral artery for 24 h. The rats were divided into 6 groups: sham, permanent middle cerebral artery occlusion (pMCAO), pMCAO with neferine and nimodipine treatment. To investigate the severity of the injury, the neurological deficit score and morphological alterations were investigated. After 24 h, the rats were evaluated to assess neurological deficit, infarct volume, morphological change, and the number of apoptotic cell deaths. In addition, the brain tissues were examined by western blot analysis to calculate the expression of proteins related to oxidative stress and apoptosis. The data showed that the neurological deficit scores and the infarct volume were significantly reduced in the neferine-treated rats compared to the vehicle group. Treatment with neferine significantly reduced oxidative stress with a measurable decrease in 4-hydroxynonenal (4-HNE), nitric oxide (NO), neuronal nitric oxide (nNOS), and calcium levels and an upregulation of Hsp70 expression. Neferine treatment also significantly decreased apoptosis, with a decrease in Bax and cleaved caspase-3 and an increase in Bcl-2. This study suggested that neferine had a neuroprotective effect on permanent cerebral ischemia in rats by diminishing oxidative stress and apoptosis.

Effects of Red Rice Bran Extract on High-Fat Diet-Induced Obesity and Insulin Resistance in Mice.

Insulin resistance is a salient player in the pathogenesis of obesity and its related abnormal glucose-insulin homeostasis. Red rice bran extract (RRBE) demonstrates several bioactive phytochemicals with anti-diabetic properties. However, little is known about its molecular mechanisms. Therefore, the present study was designed to investigate the anti-insulin resistant mechanisms of RRBE in a model of high-fat diet (HFD)-induced insulin resistance. In this study, mice were randomly divided into four groups: low-fat diet with distilled water (Group L), HFD with distilled water (Group H), HFD with 0.5 g/kg RRBE, and HFD with 1 g/kg RRBE. Metabolic parameters, histological changes in the pancreas, and gene expression levels were evaluated after treating HFD-fed mice with RRBE for six weeks. Mice from Group H exhib-ited significantly higher blood glucose levels prior to and after an oral glucose tolerance test, fasting serum insulin levels, islet size, pancreatic insulin expression levels, and lower skeletal muscle insulin-degrading enzyme (IDE) expression levels compared to Group L. In contrast, these were all significantly restored in the RRBE-treated groups. Also, RRBE treatment was found to upregulate the expression of insulin receptor substrate (IRS) and glucose transporter (GLUT) genes in the adipose tissues and GLUT genes in the muscles and livers of HFD-fed mice. According to our results, RRBE may ameliorate abnormal glucose-insulin metabolism by modulating the expression of insulin, IDE, IRS, and GLUT genes in the major metabolic target tissues of mice after being fed with HFD.

Chronic high-fat diet consumption exacerbates pyroptosis- and necroptosis-mediated HMGB1 signaling in the brain after ischemia and reperfusion injury.

Obesity is categorized as a common comorbidity found in people who experience an ischemic stroke. However, the mechanisms to explain this correlation have still not been elucidated fully. Pyroptosis and necroptosis are novel forms of programmed cell death that occur upon intracellular danger signals. The major feature of pyroptosis and necroptosis is damage to the lipid membrane, which consequently results in lytic cell death and allows the release of high mobility group box protein 1 (HMGB1) into the extracellular space. We aimed to investigate the influences of high-fat diet (HFD) consumption on cerebral ischemia and reperfusion (I/R) injury and hypothesized that HFD consumption exacerbated the activation of pyroptosis, necroptosis, and HMGB1 signaling pathways. All rats received normal diet (ND) or HFD for 16 weeks. Subsequently, both groups were divided into either a sham- or an I/R-operated group. Twenty-four hours after the surgery, all rats were evaluated for neurological deficits and then sacrificed. After I/R injury, there were more severe functional deficits and larger brain infarcts in the HFD compared with the ND group. The histological observation revealed an increase in tissue abnormalities in the HFD group, consistent with the massive reduction of intact neurons along the peri-infarct region. Furthermore, cerebral I/R injury dramatically activated the pyroptotic, necroptotic, and HMGB1 signaling pathways in HFD-fed rats compared with ND-fed rats. These findings suggest that chronic HFD consumption worsens ischemic brain pathology and leads to poor post-stroke outcomes by exacerbating pyroptotic and necroptotic cell death.

Melatonin improves cognitive function by suppressing endoplasmic reticulum stress and promoting synaptic plasticity during chronic cerebral hypoperfusion in rats.

Chronic cerebral hypoperfusion (CCH) is the most common cause of cognitive impairment, which is commonly found in Alzheimer's disease (AD) and vascular dementia (VaD). Recently, studies have demonstrated that melatonin is an effective treatment in various neurodegenerative diseases. In this study, we aimed to investigate the effects of melatonin on CCH-induced AD pathology, endoplasmic reticulum (ER) stress, and synaptic plasticity, all of which are correlated with the activation of oxidative stress, apoptosis, and cognitive impairment. CCH was induced in male Wistar rats by bilateral common carotid artery occlusion (2VO). After surgery, rats were treated with melatonin (10 mg/kg) or piracetam (600 mg/kg) by oral gavage once a day for 4 weeks. At the end of the experiment, all rats were assessed for memory impairment by using the Morris water maze test. Subsequently, rats were sacrificed, and brains were removed to determine the levels of beta-amyloid (Aß), malondialdehyde (MDA); the acetylcholinesterase (AChE) activity; subjected to terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL); and subjected to western blotting of proteins related to memory, AD pathology, oxidative stress, ER stress, and apoptosis. Melatonin alleviated brain injury during 2VO induction, as revealed by decreased the expression of AD markers, attenuated oxidative stress, suppressed the expression of proteins related to ER stress, apoptosis, and stimulated the expression of the synaptic markers resulting in promoted cognitive function. Therefore, our data demonstrated that melatonin ameliorated cognitive impairment in the 2VO model, and these beneficial effects were associated with reduction in oxidative stress, ER stress, and apoptosis.

The effects of festidinol treatment on the D-galactose and aluminum chloride-induced Alzheimer-like pathology in mouse brain.

BACKGROUND: Festidinol is a flavan-3-ol which has been shown to reduce advanced glycation end products (AGEs) and reactive oxygen species, both of which play a crucial role in the pathology of many neurodegenerative diseases. PURPOSE: This study aimed to investigate the effects of festidinol on oxidative stress, amyloidogenesis, phosphorylated tau (pTau) expression, synaptic function, and cognitive impairment, and the potential mechanisms involved, in a mouse model with an Alzheimer-like pathology. METHODS: D-galactose (150 mg/kg) and aluminum chloride (10 mg/kg) were injected intraperitoneally into 40 mice for 90 days to generate an AD mouse model with cognitive impairment. Festidinol (30 mg/kg) and donepezil (5 mg/kg) were then administered orally for 90 days after which behavior and molecular changes in the brain were measured. RESULTS: The aluminum accumulated and the expression of the cell senescence marker P16 increased after exposure to D-galactose and AlCl3 (2.5 ± 0.5 mg/kg, 149.1 ± 28.1% of control, respectively). Festidinol markedly decreased the escape latency (8.7 ± 4.3 s) and increased the number of platform crossings (8 ± 1.4 time) in the Morris water maze test. Superoxide dismutase activity was significantly elevated after festidinol administration, however there were significant reductions in the levels of 4­hydroxy-2-nonenal, receptor for advanced glycation end products, phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells (pNF-κB), and nuclear factor of activated T cells 1 (NFAT1). Festidinol attenuated amyloid beta production by reducing the mRNA of beta-site APP cleaving enzyme 1 (BACE1). Festidinol also significantly decreased the expression of pTau and phosphorylated glycogen synthase kinase 3 (148.6 ± 37.6% of control, 125.3 ± 22.6% of control, respectively). CONCLUSION: Festidinol can ameliorate learning and memory impairments by modulating amyloidogenesis, tau hyperphosphorylation, cholinergic activity, neuroinflammation, and oxidative stress, and by regulating the brain-derived neurotrophic factor signaling pathway.

Morin Attenuated Cerebral Ischemia/Reperfusion Injury Through Promoting Angiogenesis Mediated by Angiopoietin-1-Tie-2 Axis and Wnt/ß-Catenin Pathway.

Cerebral damage following cerebral ischemia/reperfusion injury affects the neurological deficits and motor impairment of stroke patients in the long-term period. Angiogenesis, the essential process for restoration of cerebral blood flow (CBF) in the ischemic brain, promotes the recovery of neurological function following ischemia. The aim of this study was to investigate the long-term effects of morin on angiogenesis and functional outcomes in a middle cerebral artery occlusion (MCAO) and reperfusion model. Male Wistar rats were subjected to MCAO, and they were administered 30 mg/kg of morin at reperfusion via i.p. injection daily for 14 days. Fourteen days after I/R injury, the rats were evaluated for the brain damage, and angiogenic factors involved in Ang1/Tie-2 and Wnt/ß-catenin signaling. In addition, at 1, 7, and 14 days after reperfusion, rotarod and pole tests were performed to investigate the functional recovery. We found morin significantly reduced the infarct size, blood-brain barrier (BBB) leakage, and apoptotic cells at 14 days after I/R injury. It also promoted angiogenesis via boosting the expression of angiogenic proteins, such as angiopoietin 1 (Ang1), Tie-2, Wnt3α, ß-catenin, and cyclin D1. Morin-mediated angiogenesis was confirmed by a significant increase in microvessel's density in the penumbra area and an increase in von Willebrand factor (vWF) protein expression of the morin-treated rats. Moreover, the rotarod and pole tests also demonstrated morin increased functional recovery in the morin-treated rats compared to the vehicle rats. Therefore, our data exposed that morin promotes angiogenesis and improves functional outcomes in MCAO and reperfusion rats.

Agomelatine Exerts an Anti-inflammatory Effect by Inhibiting Microglial Activation Through TLR4/NLRP3 Pathway in pMCAO Rats.

Cerebral ischemic stroke is one of the main causes of death and long-term disability worldwide. However, the mechanism is unclear, and treatments are limited. In this study, we aimed to investigate the anti-inflammatory effect of agomelatine in a permanent middle cerebral artery occlusion (pMCAO) model. Forty-eight male Wistar rats were randomly divided into four groups: sham, pMCAO + vehicle, pMCAO + agomelatine (40 mg/kg, i.p.), and pMCAO + melatonin (10 mg/kg, i.p.) groups. On day 1 after permanent cerebral ischemia, the animals were sacrificed, and brain tissues were collected for western blot analysis, and immunohistochemistry. Agomelatine treatment ameliorated inflammatory responses by decreasing the protein levels of trigger Toll-like receptor (TLR4)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway components together with nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome components. In addition, agomelatine suppressed microglial activation and pyroptotic cell death after cerebral ischemic injury. These results suggest that agomelatine exerts an anti-inflammatory effect and attenuates brain damage by inhibiting microglial activation through the TLR4/NLRP3 signaling pathway.

The effects of agomelatine on endoplasmic reticulum stress related to mitochondrial dysfunction in hippocampus of aging rat model.

BACKGROUND: Agomelatine, a novel antidepressant, is a melatonin MT receptor agonist and serotonin 5HT2C receptor antagonist. In this study, agomelatine was used to investigate the molecular mechanisms of hippocampal aging associated with endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and apoptosis, all of which led to short-term memory impairment. METHOD: Hippocampal aging was induced in male Wistar rats by d-galactose (D-gal) intraperitoneal injection (100 mg/kg) for 14 weeks. During the last 4 weeks of D-gal treatment, rats were treated with agomelatine (40 mg/kg) or melatonin (10 mg/kg). At the end of the experiment, all rats were assessed for short-term memory by using the Morris water maze test. Subsequently, rats were sacrified and the hippocampus was removed from each rat for determination of reactive oxygen species (ROS), malondialdehyde (MDA), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays; and immunohistochemistry related to ER stress, mitochondrial dysfunction, and apoptosis. RESULTS: Agomelatine suppressed the expression of the aging-related proteins P16 and receptor for advanced glycation endproducts (RAGE), the expression of NADPH oxidase (NOX) 2 and 4, and ROS production. This treatment also shifted the morphology of astrocytes and microglia toward homeostasis. Furthermore, agomelatine decreased inositol-requiring enzyme 1 (pIRE1), protein kinase R-like endoplasmic reticulum kinase (pPERK), and chaperone binding immunoglobulin protein (BiP), leading to suppression of ER stress markers C/EBP homologous protein (CHOP) and caspase-12. Agomelatine reduced Ca2+ from the ER and stabilized the mitochondrial membrane stability, which was denoted by the BCL2 Associated X (Bax)/B-cell lymphoma 2 (Bcl2) balance. Agomelatine decreased cleaved caspase-3 production and the Terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL)-positive area, and glutamate excitotoxicity was prevented via suppression of N-methyl-d-aspartate (NMDA) receptor subunit expression. Agomelatine exhibited effects that were similar to melatonin. CONCLUSION: Agomelatine improved neurodegeneration in a rat model of hippocampal aging by attenuating ROS production, ER stress, mitochondrial dysfunction, excitotoxicity, and apoptosis.

Melatonin attenuates reactive astrogliosis and glial scar formation following cerebral ischemia and reperfusion injury mediated by GSK-3ß and RIP1K.

Even though astrocytes have been widely reported to support several brain functions, studies have emerged that they exert deleterious effects on the brain after ischemia and reperfusion (I/R) injury. The present study investigated the neuroprotective effects of melatonin on the processes of reactive astrogliosis and glial scar formation, as well as axonal regeneration after transient middle cerebral artery occlusion. Male Wistar rats were randomly divided into four groups: sham-operated, I/R, I/R treated with melatonin, and I/R treated with edaravone. All drugs were administered via intraperitoneal injection at the onset of reperfusion and were continued until the rats were sacrificed on Day 7 or 14 after the surgery. Melatonin presented long-term benefits on cerebral damage after I/R injury, as demonstrated by a decreased infarct volume, histopathological changes, and reduced neuronal cell death. We also found that melatonin attenuated reactive astrogliosis and glial scar formation and, consequently, enhanced axonal regeneration and promoted neurobehavioral recovery. Furthermore, glycogen synthase kinase-3 beta (GSK-3ß) and receptor-interacting serine/threonine-protein 1 kinase (RIP1K), which had previously been revealed as proteins involved in astrocyte responses, were significantly reduced after melatonin administration. Taken together, melatonin effectively counteracted the deleterious effects due to astrocyte responses and improved axonal regeneration to promote functional recovery during the chronic phase of cerebral I/R injury by inhibiting GSK-3ß and RIP1K activities.