Neuroprotective effect of bicyclol in rat ischemic stroke: down-regulates TLR4, TLR9, TRAF6, NF-κB, MMP-9 and up-regulates claudin-5 expression

TAT-W61 peptide attenuates neuronal injury through blocking the binding of S100b to the V-domain of Rage during ischemic stroke

Ischemic stroke is a devastative nervous system disease associated with high mortality and morbidity rates. Unfortunately, no clinically effective neuroprotective drugs are available now. In ischemic stroke, S100 calcium-binding protein b (S100b) binds to receptor for advanced glycation end products (Rage), leading to the neurological injury. Therefore, disruption of the interaction between S100B and Rage can rescue neuronal cells. Here, we designed a peptide, termed TAT-W61, derived from the V domain of Rage which can recognize S100b. Intriguingly, TAT-W61 can reduce the inflammatory caused by ischemic stroke through the direct binding to S100b. The further investigation demonstrated that TAT-W61 can improve pathological infarct volume and reduce the apoptotic rate. Particularly, TAT-W61 significantly improved the learning ability, memory, and motor dysfunction of the mouse in the ischemic stroke model. Our study provides a mechanistic insight into the abnormal expression of S100b and Rage in ischemic stroke and yields an invaluable candidate for the development of drugs in tackling ischemic stroke. KEY MESSAGES: S100b expression is higher in ischemic stroke, in association with a high expression of many genes, especially of Rage. S100b is directly bound to the V-domain of Rage. Blocking the binding of S100b to Rage improves the injury after ischemic stroke.

Bicyclol Attenuates Obesity-Induced Cardiomyopathy via Inhibiting NF-κB and MAPK Signaling Pathways

PURPOSE

Schisandra is a well-known traditional Chinese medicine in East Asia. As a traditional Chinese medicine derivative with Schisandra chinensis as raw material, bicyclol is well known for its significant anti-inflammatory effect. Chronic inflammation plays a significant part in obesity-induced cardiomyopathy. Our purpose was to explore the effect and mechanism of bicyclol on obesity-induced cardiomyopathy.

METHODS

Mice fed with a high-fat diet (HFD) and cardiomyocytes stimulated by palmitic acid (PA) were used as models of obesity-related cardiomyopathy in vivo and in vitro, respectively. The therapeutic effect of bicyclol on pathological changes such as myocardial hypertrophy and fibrosis was evaluated by staining cardiac tissue sections. PCR was used to detect inflammatory factors in H9c2 cells and animal heart tissue after bicyclol treatment. Then, we used western blotting to detect the expression levels of the myocardial hypertrophy related protein, myocardial fibrosis related protein, NF-κB and MAPK pathways.

RESULTS

Our results indicated that bicyclol treatment significantly alleviates HFD-induced myocardial inflammation, fibrosis, and hypertrophy by inhibiting the MAPK and NF-κB pathways. Similar to animal level results, bicyclol could significantly inhibit PA-induced inflammation and prevent NF-κB and MAPK pathways from being activated.

CONCLUSION

Our results showed that bicyclol has potential as a drug to treat obesity-induced cardiomyopathy.

Geniposide protected against cerebral ischemic injury through the anti-inflammatory effect via the NF-κB signaling pathway

Context

Accumulated evidence indicates that geniposide exhibits neuroprotective effects in ischemic stroke. However, the potential targets of geniposide remain unclear.

Objective

We explore the potential targets of geniposide in ischemic stroke.

Materials and methods

Adult male C57BL/6 mice were subjected to the middle cerebral artery occlusion (MCAO) model. Mice were randomly divided into five groups: Sham, MCAO, and geniposide-treated (i.p. twice daily for 3 days before MCAO) at doses of 25, 75, or 150 mg/kg. We first examined the neuroprotective effects of geniposide. Then, we further explored via biological information analysis and verified the underlying mechanism in vivo and in vitro.

Results

In the current study, geniposide had no toxicity at concentrations of up to 150 mg/kg. Compared with the MCAO group, the 150 mg/kg group of geniposide significantly (P < 0.05) improved neurological deficits, brain edema (79.00 ± 0.57% vs 82.28 ± 0.53%), and infarct volume (45.10 ± 0.24% vs 54.73 ± 2.87%) at 24 h after MCAO. Biological information analysis showed that the protective effect was closely related to the inflammatory response. Geniposide suppressed interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) expression in the brain homogenate, as measured by enzyme-linked immunosorbent assay (ELISA). Geniposide upregulated A20 and downregulated TNF receptor-associated factor-6 and nuclear factor kappa-B phosphorylation in the MCAO model and lipopolysaccharide-treated BV2 cells at 100 μM.

Conclusions

Geniposide exhibited a neuroprotective effect via attenuating inflammatory response, as indicated by biological information analysis, in vivo and in vitro experiments, which may provide a potential direction for the application of geniposide in the treatment of ischemic stroke.

Variant Rs556621 on Chromosome 6p21.1 and the Risk of Ischemic Stroke in Chinese Populations: A Meta-Analysis

There are inconsistencies in the published findings on the association of variant rs556621 in an intergenic region on Chromosome 6p21.1 with the risk of developing ischemic stroke (IS) and a major IS subtype (large artery atherosclerosis, LAA) in Chinese populations. We conducted a meta-analysis to evaluate the association of variant rs556621 with IS/LAA risk using ten studies involving 3644 IS cases and 3692 controls (including seven studies involving 2268 LAA cases and 2268 controls) from China. The AA genotype increased IS risk (AA versus CC: odds ratio [OR] 1.19, 95% confidence interval [CI] 1.03-1.36, P = 0.015; AA versus CA + CC: OR 1.23, 95% CI 1.09-1.39, P = 0.001). Subgroup analysis also suggested that rs556621 contributed to the risk of IS both in Chinese Han and the miscellaneous group. However, these results were stable in Chinese Han but not in the miscellaneous group. When restricting our analysis to the LAA subtype, similar results were obtained. This meta-analysis is the first meta-analysis on the correlation between rs556621 and the susceptibility of IS/LAA and demonstrates that rs556621 is associated with IS/LAA risk in Chinese populations. Further meta-analysis warrants larger well-designed investigations to assess these effects.

Stellate ganglion block reduces inflammation and improves neurological function in diabetic rats during ischemic stroke

Diabetes mellitus is an independent risk factor for ischemic stroke. Both diabetes mellitus and stroke are linked to systemic inflammation that aggravates patient outcomes. Stellate ganglion block can effectively regulate the inflammatory response. Therefore, it is hypothesized that stellate ganglion block could be a potential therapy for ischemic stroke in diabetic subjects. In this study, we induced diabetes mellitus in rats by feeding them a high-fat diet for 4 successive weeks. The left middle cerebral artery was occluded to establish models of ischemic stroke in diabetic rats. Subsequently, we performed left stellate ganglion block with 1% lidocaine using the percutaneous posterior approach 15 minutes before reperfusion and again 20 and 44 hours after reperfusion. Our results showed that stellate ganglion block did not decrease the blood glucose level in diabetic rats with diabetes mellitus but did reduce the cerebral infarct volume and the cerebral water content. It also improved the recovery of neurological function, increased 28-day survival rate, inhibited Toll like receptor 4/nuclear factor kappa B signaling pathway and reduced inflammatory response in the plasma of rats. However, injection of Toll like receptor 4 agonist lipopolysaccharide 5 minutes before stellate ganglion block inhibited the effect of stellate ganglion block, whereas injection of Toll like receptor 4 inhibitor TAK242 had no such effect. We also found that stellate ganglion block performed at night had no positive effect on diabetic ischemic stroke. These findings suggest that stellate ganglion block is a potential therapy for diabetic ischemic stroke and that it may be mediated through the Toll like receptor 4/nuclear factor kappa B signaling pathway. We also found that the therapeutic effect of stellate ganglion block is affected by circadian rhythm.

Neuroprotective Effect of Daidzein Extracted From Pueraria lobate Radix in a Stroke Model Via the Akt/mTOR/BDNF Channel

Daidzein is a plant isoflavonoid primarily isolated from Pueraria lobate Radix as the dry root of P. lobata (Wild.) Ohwi, have long been used as nutraceutical and medicinal herb in China. Despite the report that daidzein can prevent neuronal damage and improve outcome in experimental stroke, the mechanisms of this neuroprotective action have been not fully elucidated. The aim of this study was to determine whether the daidzein elicits beneficial actions in a stroke model, namely, cerebral ischemia/reperfusion (I/R) injury, and to reveal the underlying neuroprotective mechanisms associated with the regulation of Akt/mTOR/BDNF signal pathway. The results showed that I/R, daidzein treatment significantly improved neurological deficits, infarct volume, and brain edema at 20 and 30 mg/kg, respectively. Meanwhile, it was found out that the pretreatment with daidzein at 20 and 30 mg/kg evidently improved striatal dopamine and its metabolite levels. In addition, daidzein treatment reduced the cleaved Caspase-3 level but enhanced the phosphorylation of Akt, BAD and mTOR. Moreover, daidzein at 30 mg/kg treatment enhanced the expression of BDNF and CREB significantly. This protective effect of daidzein was ameliorated by inhibiting the PI3K/Akt/mTOR signaling pathway using LY294002. To sum up, our results demonstrated that daidzein could protect animals against ischemic damage through the regulation of the Akt/mTOR/BDNF channel, and the present study may facilitate the therapeutic research of stroke.

The natural (poly)phenols as modulators of microglia polarization via TLR4/NF-κB pathway exert anti-inflammatory activity in ischemic stroke

Increasing evidences suggest that inflammation plays a key role in the pathogenesis of stroke, a devastating disease second only to cardiac ischemia as a cause of death worldwide. Microglia are the first non-neuronal cells on the scene during the innate immune response to acute ischemic stroke. Microglia respond to acute brain injury by activating and developing classic M1-like (pro-inflammatory) or alternative M2-like (anti-inflammatory) phenotypes. M1 microglia produce pro-inflammatory cytokines to exacerbate neural death, astrocyte apoptosis, and blood brain barrier (BBB) disruption, while M2 microglia play the opposite role. NF-κB, a central regulator of the inflammatory response, was responsible for microglia M1 and M2 polarization. NF-κB p65 and p50 form a heterodimer to initiate a pro-inflammatory cytokine response, which enhances M1 activation and impair M2 response of microglia. TLR4, expressed on the surface of microglia, plays an important role in activating NF-κB, ultimately causing the M1 response of microglia. Therefore, modulation of microglial phenotypes via TLR4/NF-κB signaling pathway may be a promising therapeutic approach for ischemic stroke. Dietary (poly)phenols are present in various foods, which have shown promising protective effects on ischemic stroke. In vivo studies strongly suggest that many (poly)phenols have a pronounced impact on ischemic stroke, as demonstrated by lower neuroinflammation. Thus, this review focuses on the anti-inflammatory properties of dietary (poly)phenols and discusses their effects on the polarization of microglia through modulating TLR4/NF-κB signaling pathway in the ischemic stroke.

Bioactive Ingredients from Nitraria tangutorun Bobr. Protect Against Cerebral Ischemia/Reperfusion Injury Through Attenuation of Oxidative Stress and the Inflammatory Response

Nitraria tangutorun Bobr. has been used for thousands of years as a native folk medicine to alleviate dizziness and neurasthenia due to oxygen. In our previous study, natural antioxidant components (namely, NJBE) were isolated from industrial N. tangutorun Bobr. juice byproducts (NJBE) from the Qinghai-Tibet plateau. The current investigation assessed the effects of NJBE on ischemic stroke in mice and the potential mechanisms. C57BL/6 mice received NJBE (25, 50, or 100 mg/Kg) by gavage for 14 days and then stroke was induced by the middle cerebral artery occlusion (MCAO) model, followed by reperfusion for 72 h. The evaluation of brain infarct size, behavioral tests, and functional assessments was conducted to assess the effects of NJBE after MCAO. Our results suggested that NJBE significantly decreases infarct size, improves neurological deficits, as well as reduces the number of GFAP⁺ and Iba-1⁺ cells after MCAO. NJBE inhibited nitric oxide and malondialdehyde production in the ischemic brain. Meanwhile, it attenuated the expressions of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Also, NJBE significantly attenuated the expression levels of proinflammatory indicators, including TNF-α, IL-1β, IL-6, and IL-12. This process was accompanied by the downregulation of TLR4, TRAF6, pIκB/pIκB, and MMP9 expression and the upregulation of claudin-5 expression. NJBE induced improvements in brain injury. The neuroprotective effect of NJBE provides evidence for its potential application in stroke treatment.

Analgecine regulates microglia polarization in ischemic stroke by inhibiting NF-κB through the TLR4 MyD88 pathway

Therapeutic strategies used to attenuate inflammation and to increase recovery of neurons after a stroke include microglia anti-inflammatory (M2) polarization and repression of proinflammatory (M1). Extracts isolated from Vaccina variola-inoculated rabbit skin, for example analgecine (AGC), have been used as a therapy for patients experiencing lower back pain associated with degenerative diseases of the spine for about twenty years. In the study presented here, neuroprotective effect associated with AGC was analyzed as well as the anti-inflammatory mechanism linked to AGC in terms of attenuating microglia-mediated neuronal damage. Rats were intravenously injected with AGC after middle cerebral artery occlusion (MCAO), which showed to suppress neuronal loss and reduce neurological deficits. In addition, AGC inhibited pro-inflammatory cytokine release and increased anti-inflammatory cytokines. Furthermore, this study revealed that treatment with AGC supported microglia transition from M1 to M2 in both oxygen-glucose deprivation/reperfusion (OGD/R) and LPS/IFN-γ induced microglia cells, as well as indirectly inhibited LPS/IFN-γ-induced neuronal damage through the modulation of microglial polarization. It is also important to note that AGC inhibited NF-κB p65 phosphorylation through repressing TLR4/Myd88/TRAF6 signaling pathway. In addition, we found that TLR4 inhibition by AGC depended on Myd88. Altogether, this work supports that AGC inhibits M1 microglial polarization and promotes anti-inflammation independently and dependently on TLR4/MyD88. Since it is shown to have neuroprotective effects in this study, AGC has great potential to be used in the clinic to reduce inflammation and aid in recovery after stroke.

Curcumin ameliorates ischemic stroke injury in rats by protecting the integrity of the blood-brain barrier

The blood-brain barrier (BBB) is critical for proper cerebral homeostasis and its dysfunction during ischemic stroke can result in significant neurological injury. The major goal of the present study was to identify whether curcumin pretreatment possessed protective effects on BBB integrity during the 24 h of acute ischemic brain injury. To investigate the protective effects of curcumin, male Sprague-Dawley rats were divided into multiple groups, including sham, middle cerebral artery occlusion/reperfusion (MCAO/R) vehicle and curcumin pretreated MCAO/R groups. The effects of curcumin were measured by analyzing neurological deficits, infarct size, BBB permeability and expression levels of permeability-related proteins in the brain. It was found that curcumin pretreatment significantly improved neurological scores, decreased infarct size, and protected synaptic remodeling of hippocampal neurons and upregulated the protein expression level of tight junction proteins, ZO-1, occludin and claudin-5 in ischemic rat brains. Furthermore, curcumin pretreatment before stroke was shown to downregulate the phosphorylation of NF-κB and MMP-9, which are central mediators of inflammation. The results from the present study indicated that curcumin pretreatment ameliorated ischemic stroke injury by protecting BBB integrity and synaptic remodeling, as well as inhibiting inflammatory responses.

Neuroprotective effects of microRNA-140-5p on ischemic stroke in mice via regulation of the TLR4/NF-κB axis

BACKGROUND AND AIM

Ischemic stroke is one of the main causes of death worldwide and permanent global disability. On the basis of existing literature data, the study was carried out in an effort to explore how miR-140-5p affects ischemic stroke and whether the mechanism relates to toll-like receptor-4 (TLR4) and nuclear factor-kappa B (NF-κB).

METHODS

Firstly, middle cerebral artery occlusion (MCAO) was performed to establish mouse models of ischemic stroke in vivo, while primary neurons were exposed to oxygen-glucose deprivation (OGD) to set up an ischemic stroke model in vitro. RT-qPCR was then applied to detect the miR-140-5p expression patterns, whereas Western blot was adopted to detect the expression patterns of TLR4, NF-κB, and apoptosis-related factors. In addition, based gain-function of experiments using miR-140-5p mimic and TLR4 over-expression plasmid, neurological function score, TTC staining, TUNEL staining, as well as flow cytometry were carried out to evaluate the effects of miR-140-5p and TLR4 on MCAO mice and OGD neurons. Moreover, dual-luciferase reporter assay was applied to validate the targeting relationship between miR-140-5p and TLR4.

RESULTS

Initial findings revealed that miR-140-5p was poorly-expressed, while TLR4 was highly-expressed in ischemic stroke. It was verified that miR-140-5p targeted TLR4 and downregulated its expression. MiR-140-5p over-expression was observed to inhibit the apoptosis of neurons under OGD exposure and restrain the progression of ischemic stroke, while TLR4 over-expression promoted the apoptosis and disease progression. Besides, miR-140-5p over-expression led to a decrease in NF-κB protein levels, which were increased by TLR4 over-expression.

CONCLUSION

In conclusion, our data indicates that miR-140-5p over-expression may be instrumental for the therapeutic targeting of ischemic stroke by alleviating neuron injury with the involvement of the TLR4/NF-κB axis.

Therapeutic potential of bicyclol in liver diseases: Lessons from a synthetic drug based on herbal derivative in traditional Chinese medicine

Bicyclol, an innovative chemical drug with proprietary intellectual property rights in China, is based on derivative of traditional Chinese medicine (TCM) Schisandra chinensis (Wuweizi) of North. Mounting data has proved that bicyclol has therapeutic potential in various pathological conditions in liver. In this narrative review, we provide the first summary of pharmacological activities, pharmacokinetic characteristics and toxicity of bicyclol, and discuss future research perspectives. Our results imply that bicyclol has a wide spectrum of pharmacological properties, including anti-viral, anti-inflammatory, immuno-regulatory, anti-oxidative, antisteatotic, anti-fibrotic, antitumor, cell death regulatory effects and modulation of heat shock proteins. Pharmacokinetic studies have indicated that bicyclol is the main substrate of CYP3A/2E1. Additionally, no obvious drug interactions have been found when bicyclol is administered simultaneously with other prescriptions. Furthermore, the results of chronic toxicity have strongly addressed that bicyclol has no noticeable toxic effects on all biochemical indices and pathological examinations of the main organs. In view of good pharmacological actions and safety, bicyclol is anticipated to be a potential candidate for various liver diseases, including acute liver injury, fulminant hepatitis, non-alcoholic fatty liver disease, fibrosis and hepatocellular carcinoma. Further studies are therefore required to delineate its molecular mechanisms and targets to confer this well-designed drug a far greater potency. We hope that bicyclol-based therapeutics for liver diseases might be broadly used in clinical practice worldwide.

Roles of TRAFs in Ischemia-Reperfusion Injury

Tumor necrosis factor receptor-associated factor (TRAF) proteins are a family of signaling molecules that function downstream of multiple receptor signaling pathways, and they play a pivotal role in the regulation of intracellular biological progresses. These TRAF-dependent signaling pathways and physiological functions have been involved in the occurrence and progression of ischemia-reperfusion injury (IRI), which is a common pathophysiological process that occurs in a wide variety of clinical events, including ischemic shock, organ transplantation, and thrombolytic therapy, resulting in a poor prognosis and high mortality. IRI occurs in multiple organs, including liver, kidney, heart, lung, brain, intestine, and retina. In recent years, mounting compelling evidence has confirmed that the genetic alterations of TRAFs can cause subversive phenotype changes during IRI of those organs. In this review, based on current knowledge, we summarized and analyzed the regulatory effect of TRAFs on the IRI of various organs, providing clear direction and a firm theoretical basis for the development of treatment strategies to manipulate TRAF proteins or TRAF-dependent signaling pathways in IRI-related diseases.

Sirt1-ROS-TRAF6 Signaling-Induced Pyroptosis Contributes to Early Injury in Ischemic Mice

Stroke is an acute cerebro-vascular disease with high incidence and poor prognosis, most commonly ischemic in nature. In recent years, increasing attention has been paid to inflammatory reactions as symptoms of a stroke. However, the role of inflammation in stroke and its underlying mechanisms require exploration. In this study, we evaluated the inflammatory reactions induced by acute ischemia and found that pyroptosis occurred after acute ischemia both in vivo and in vitro, as determined by interleukin-1β, apoptosis-associated speck-like protein, and caspase-1. The early inflammation resulted in irreversible ischemic injury, indicating that it deserves thorough investigation. Meanwhile, acute ischemia decreased the Sirtuin 1 (Sirt1) protein levels, and increased the TRAF6 (TNF receptor associated factor 6) protein and reactive oxygen species (ROS) levels. In further exploration, both Sirt1 suppression and TRAF6 activation were found to contribute to this pyroptosis. Reduced Sirt1 levels were responsible for the production of ROS and increased TRAF6 protein levels after ischemic exposure. Moreover, N-acetyl-L-cysteine, an ROS scavenger, suppressed the TRAF6 accumulation induced by oxygen-glucose deprivation via suppression of ROS bursts. These phenomena indicate that Sirt1 is upstream of ROS, and ROS bursts result in increased TRAF6 levels. Further, the activation of Sirt1 during the period of ischemia reduced ischemia-induced injury after 72 h of reperfusion in mice with middle cerebral artery occlusion. In sum, these results indicate that pyroptosis-dependent machinery contributes to the neural injury during acute ischemia via the Sirt1-ROS-TRAF6 signaling pathway. We propose that inflammatory reactions occur soon after oxidative stress and are detrimental to neuronal survival; this provides a promising therapeutic target against ischemic injuries such as a stroke.

PRDX1 enhances cerebral ischemia-reperfusion injury through activation of TLR4-regulated inflammation and apoptosis

Stroke is still a leading cause of death across the world. Despite various signals or molecules that contribute to the pathophysiological process have been investigated, the exact molecular mechanisms revealing stroke damage still remain to be explored. Peroxiredoxin 1 (PRDX1) has been identified as a stress-induced macrophage redox protein with multiple functions. Although PRDX1 is a critical factor related to the regulation of immunity, inflammation, apoptosis and oxidative stress, its effects on cerebral ischemia-reperfusion (I-R) injury were presently unclear. In the study, by using a mouse model of I-R injury, we found that PRDX1 expression was up-regulated during I-R injury in a time-dependent manner. Additionally, PRDX1-knockout mice showed reduced infarction area and alleviated neuropathological scores with decreased brain water contents. Furthermore, cell death and inflammatory response in mice with cerebral I-R injury were markedly attenuated by PRDX1 knockout, which were associated with the blockage of Caspase-3 and nuclear factor-κB (NF-κB) signaling pathways. Mechanistically, PRDX1-regulated cerebral I-R injury was through the promotion of toll-like receptor-4 (TLR4), as proved by the evidence that TLR4 suppression abrogated the exacerbated effect of TLR4 on inflammatory response and apoptosis in oxygen and glucose deprivation (OGD)-treated primary microglial cells. These data demonstrated that PRDX1 contributed to cerebral stroke by interacting with TLR4, providing an effective therapeutic approach for cerebral I-R injury.

Effect of β-patchoulene on cerebral ischemia-reperfusion injury and the TLR4/NF-κB signaling pathway

β-patchoulene (β-PAE), an active constituent of the Pogostemon cablin, is well known for its anti-inflammatory and antioxidative functions in various diseases. However, little is known about the impact of β-PAE on the cerebral ischemia-reperfusion (I/R) injury. The current study aimed to determine the neuroprotective effect of β-PAE and the underlying mechanisms on cerebral I/R injury. Following pretreatment with β-PAE (10 mg/kg body weight) by tail intravenous injection for 1 h, Sprague-Dawley rats were subjected to middle cerebral artery occlusion for 2 h and reperfusion for 24 h. The results indicated that pretreatment with β-PAE could diminish the infarct volume, decrease the brain water content, reduce the neurological deficit score and restore the mitochondrial membrane potential, compared with the untreated I/R injury group. Furthermore, cell apoptosis was markedly suppressed by β-PAE, and this effect was associated with the decreased apoptosis regulator BAX/apoptosis regulator Bcl-2 expression ratio and caspase-3 activity. In addition, β-PAE significantly inhibited the release of proinflammatory factors, including tumor necrosis factor-α, interleukin (IL)-1β and IL-6. Superoxide generation and malondialdehyde levels were reduced while the levels of glutathione peroxidase and superoxide dismutase were elevated following treatment with β-PAE, indicating the antioxidative role of β-PAE in cerebral I/R injury. Furthermore, the Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway was inhibited by β-PAE, as demonstrated by the decreased TLR4 expression and nuclear translocation of p65, and increased IκBα level. Taken together, the results suggested that β-PAE may exhibit a neuroprotective effect on cerebral I/R injury in rats through inactivating the TLR4/NF-κB signaling pathway.

Neutrophil-mediated and low density lipoprotein receptor-mediated dual-targeting nanoformulation enhances brain accumulation of scutellarin and exerts neuroprotective effects against ischemic stroke

Delivery of poorly permeable drugs across the blood-brain barrier (BBB) is a great challenge in the treatment of ischemic stroke.

Potential Medications or Compounds Acting on Toll-like Receptors in Cerebral Ischemia

Background:

Toll-like receptors play an integral role in the process of inflammatory response after ischemic in-jury. The therapeutic potential acting on TLRs is worth of evaluations. The aim of this review was to introduce readers some potential medications or compounds which could alleviate the ischemic damage via TLRs.

Methods:

Research articles online on TLRs were reviewed. Categorizations were listed according to the follows, methods acting on TLRs directly, modulations of MyD88 or TRIF signaling pathway, and the ischemic tolerance induced by the pre-conditioning or postconditioning with TLR ligands or minor cerebral ischemia via acting on TLRs.

Results:

There are only a few studies concerning on direct effects. Anti-TLR4 or anti-TLR2 therapies may serve as promis-ing strategies in acute events. Approaches targeting on inhibiting NF-κB signaling pathway and enhancing interferon regu-latory factor dependent signaling have attracted great interests. Not only drugs but compounds extracted from traditional Chinese medicine have been used to identify their neuroprotective effects against cerebral ischemia. In addition, many re-searchers have reported the positive therapeutic effects of preconditioning with agonists of TLR2, 3, 4, 7 and 9. Several trails have also explored the potential of postconditioning, which provide a new idea in ischemic treatments. Considering all the evidence above, many drugs and new compounds may have great potential to reduce ischemic insults.

Conclusion:

This review will focus on promising therapies which exerting neuroprotective effects against ischemic injury by acting on TLRs.

Atorvastatin Attenuates Cognitive Deficits and Neuroinflammation Induced by Aβ1-42 Involving Modulation of TLR4/TRAF6/NF-κB Pathway

Inflammatory damage aggravates the progression of Alzheimer's disease (AD) and the mechanism of inflammatory damage may provide a new therapeutic window for the treatment of AD. Toll-like receptor 4 (TLR4)-mediated signaling can regulate the inflammatory process. However, changes in TLR4 signaling pathway induced by beta-amyloid (Aβ) have not been well characterized in brain, especially in the hippocampus. In the present study, we explored the changes of TLR4 signaling pathway induced by Aβ in the hippocampus and the role of atorvastatin in modulating this signal pathway and neurotoxicity induced by Aβ. Experimental AD rats were induced by intrahippocampal injection of Aβ_1-42, and the rats were treated with atorvastatin by oral gavage from 3 weeks before to 6 days after injections of Aβ_1-42. To determine the spatial learning and memory ability of rats in the AD models, Morris water maze (MWM) was performed. The expression of the glial fibrillary acidic protein (GFAP), ionized calcium binding adapter molecule-1 (Iba-1), TLR4, tumor necrosis factor receptor-associated factor 6 (TRAF6), and nuclear transcription factor (NF)-κB (NF-κB) protein in the hippocampus was detected by immunohistochemistry and Western blot. Compared to the control group, increased expression of TLR4, TRAF6, and NF-κB was observed in the hippocampus at 7 days post-injection of Aβ (P < 0.01). Furthermore, atorvastatin treatment significantly ameliorated cognitive deficits of rats, attenuated microglia and astrocyte activation, inhibited apoptosis, and down-regulated the expression of TLR4, TRAF6, and NF-κB, both at the mRNA and protein levels (P < 0.01). TLR4 signaling pathway is thus actively involved in Aβ-induced neuroinflammation and atorvastatin treatment can exert the therapeutic benefits for AD via the TLR4 signaling pathway.

An Angiopep-2 functionalized nanoformulation enhances brain accumulation of tanshinone IIA and exerts neuroprotective effects against ischemic stroke

Effective intervention against ischemic stroke requires delivery of potent neuroprotective drugs to the brain.

Neutrophil affinity for PGP and HAIYPRH (T7) peptide dual-ligand functionalized nanoformulation enhances the brain delivery of tanshinone IIA and exerts neuroprotective effects against ischemic stroke by inhibiting proinflammatory signaling pathways

A great challenge to the therapy of ischemic stroke is the poor physicochemical properties and inability of the drug to cross the blood–brain barrier (BBB).

Ulinastatin protects brain against cerebral ischemia/reperfusion injury through inhibiting MMP-9 and alleviating loss of ZO-1 and occludin proteins in mice

BACKGROUND

The effects of Ulinastatin (UTI) on the blood-brain barrier (BBB) in the acute phase of cerebral ischemia/reperfusion (I/R) are not clear. This study was to investigate the potential protective effects of UTI on the BBB and the underlying mechanisms.

METHODS

Male CD-1 mice were subjected to transient middle cerebral artery occlusion (tMCAO) and randomly assigned to four groups: Sham (sham-operated), tMCAO (tMCAO+0.9% saline), UTI-L (tMCAO+UTI 1500U/100g) and UTI-H (tMCAO+UTI 3000U/100g) group. UTI was administered immediately after reperfusion in the UTI-L and UTI-H groups. At 24h after reperfusion, the neurological deficit, brain water content, and infarct volume were determined. Western blot and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to examine the expression of matrix metalloproteinase (MMP)-9, Zonula occludens-1 (ZO-1) and occludin in ischemic cerebral cortex. The integrity of the BBB was assessed by the leakage of Evans blue.

RESULTS

Compared with tMCAO group, both UTI-L and UTI-H groups showed significantly (P<0.001) ameliorated the neurological deficit (2.00±0.71 and 1.60±0.55 vs. 4.60±0.55), lessened brain water content (82.99%±0.21% and 82.05%±0.59% vs. 84.28%±0.0.57%) and decreased the infarct volume (38.52%±1.72% and 24.78%±1.20% vs. 49.48%±1.93%). In addition, significantly (P<0.001) decreased expression of MMP-9 (0.48±0.06 and 0.37±0.05 vs.0.76±0.10 for protein and 2.88±0.23 and 2.17±0.16 vs. 3.90±0.24 for mRNA) and alleviated loss of ZO-1 (0.19±0.04 and 0.24±0.05 vs. 0.25±0.03) and occludin (0.74±0.08 and 0.87±0.07 vs. 0.94±0.06) proteins were observed in both UTI-L and UTI-H groups.

CONCLUSION

UTI protects the brain against ischemic injury potentially via down-regulating the expression of MMP-9 and alleviating loss of ZO-1 and occludin proteins to restore the BBB permeability.

Activation of Alpha-7 Nicotinic Acetylcholine Receptor Reduces Brain Edema in Mice with Ischemic Stroke and Bone Fracture

Stroke is an important risk factor for bone fracture. We showed previously that bone fracture at the acute stage of ischemic stroke worsens, and activation of α-7 nicotinic acetylcholine receptor (α-7 nAchR) improves, stroke recovery by attenuating inflammation. We hypothesized that activation of α-7 nAchR also improves the blood-brain barrier (BBB) integrity. Permanent distal middle cerebral artery occlusion (pMCAO) was performed on C57BL/6J mice followed by tibia fracture 1 day later. Mice were treated with 0.8 mg/kg PHA 568487 (PHA, α-7 nAchR-specific agonist), 6 mg/kg methyllycaconitine (MLA, α-7 nAchR antagonist), or saline 1 and 2 days after pMCAO. Brain water content, the expression of monoamine oxidase B (MAO-B), and tight junction protein (claudin-5) were assessed. We found that tibia fracture increased water content in the ischemic stroke brain (p = 0.006) and MAO-B-positive astrocytes (p < 0.001). PHA treatment reduced water content and MAO-B-positive astrocytes and increased claudin-5 expression in stroke and stroke + tibia fracture mice (p < 0.05), while MLA had the opposite effect. Our findings suggest that in addition to inhibiting inflammation, activation of α-7 nAchR also reduces brain edema, possibly through diminished astrocyte oxidative stress and improved BBB integrity. Thus, the α-7 nAchR-specific agonist could be developed into a new therapy for improving recovery of patients with stroke or stroke + bone fracture.

The Role of Toll-Like Receptors and Vitamin D in Cardiovascular Diseases-A Review

Cardiovascular diseases are the leading cause of mortality worldwide. Therefore, a better understanding of their pathomechanisms and the subsequent implementation of optimal prophylactic and therapeutic strategies are of utmost importance. A growing body of evidence states that low-grade inflammation is a common feature for most of the cardiovascular diseases in which the contributing factors are the activation of toll-like receptors (TLRs) and vitamin D deficiency. In this article, available data concerning the association of cardiovascular diseases with TLRs and vitamin D status are reviewed, followed by a discussion of new possible approaches to cardiovascular disease management.

Dioscin inhibits ischemic stroke‑induced inflammation through inhibition of the TLR4/MyD88/NF‑κB signaling pathway in a rat model

Diosgenin, as an essential natural steroidal saponin, can be extracted from numerous sources, primarily from fenugreek. It is an important raw material for the synthesis of steroid hormone drugs. It exhibits antitumor, anti‑inflammatory, antioxidation and several other significant pharmacologic actions, and is of high pharmaceutical value. In the present study, the activities and underlying mechanisms of dioscin in the inhibition of ischemic stroke in rats were investigated. Inflammatory responses wer analyzed using ELISA kits and caspase‑3 and caspase‑9 activity was analyzed using Caspase‑3 and caspase‑9 activity kits. Western blot analysis was used to measure Toll‑like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nuclear factor‑κB (NF‑κB), transforming growth factor‑β1 (TGF‑β1), high‑mobility group protein 1 (HMGB‑1), interleukin‑1 receptor‑associated kinase 1 (IRAK1), and tumor necrosis factor receptor‑associated factor 6 (TRAF6) protein expression. Dioscin inhibited infarct volume and neurological scores in the ischemic stroke rat model. The results demonstrated that dioscin reduced inflammatory responses, and suppressed the expression of TLR4, MyD88, NF‑κB, TGF‑β1, HMGB‑1, IRAK1, and TRAF6 in the rat ischemic stroke model. Taken together, these findings suggested that dioscin inhibited ischemic stroke‑induced inflammation through inhibition of the TLR4/MyD88/NF‑kB‑induced inflammation the rat model, which provided novel insights into the mechanisms underlying the effect of dioscin as an anti‑inflammatory candidate for the treatment of ischemic stroke in in the future.

Xyloketal B alleviates cerebral infarction and neurologic deficits in a mouse stroke model by suppressing the ROS/TLR4/NF-κB inflammatory signaling pathway

Xyloketal B (Xyl-B) is a novel marine compound isolated from mangrove fungus Xylaria sp. We previously demonstrated that pretreatment with Xyl-B exerted neuroprotective effects and attenuated hypoxic-ischemic brain injury in neonatal mice. In the present study we investigated the neuroprotective effects of pre- and post-treatment with Xyl-B in adult mice using a transient middle cerebral artery occlusion (tMCAO) model, and explored the underlying mechanisms. Adult male C57 mice were subjected to tMCAO surgery. For the pre-treatment, Xyl-B was given via multiple injections (12.5, 25, and 50 mg·kg^-1·d^-1, ip) 48 h, 24 h and 30 min before ischemia. For the post-treatment, a single dose of Xyl-B (50 mg/kg, ip) was injected at 0, 1 or 2 h after the onset of ischemia. The regional cerebral perfusion was monitored using a laser-Doppler flowmeter. TTC staining was performed to determine the brain infarction volume. We found that both pre-treatment with Xyl-B (50 mg/kg) and post-treatment with Xyl-B (50 mg/kg) significantly reduced the infarct volume, but had no significant hemodynamic effects. Treatment with Xyl-B also significantly alleviated the neurological deficits in tMCAO mice. Furthermore, treatment with Xyl-B significantly attenuated ROS overproduction in brain tissues; increased the MnSOD protein levels, suppressed TLR4, NF-κB and iNOS protein levels; and downregulated the mRNA levels of proinflammatory cytokines, including IL-1β, TNF-α, IL-6 and IFN-γ. Moreover, Xyl-B also protected blood-brain barrier integrity in tMCAO mice. In conclusion, Xyl-B administered within 2 h after the onset of stroke effectively protects against focal cerebral ischemia; the underlying mechanism may be related to suppressing the ROS/TLR4/NF-κB inflammatory signaling pathway.

Tumor necrosis factor receptor-associated factor 6 participates in early brain injury after subarachnoid hemorrhage in rats through inhibiting autophagy and promoting oxidative stress

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is a member of the TRAF family and an important multifunctional intracellular adaptin of the tumor necrosis factor superfamily and toll/IL-1 receptor (TIR) superfamily. TRAF6 has been studied in several central nervous system diseases, including ischemic stroke, traumatic brain injury, and neurodegenerative diseases, but its role in subarachnoid hemorrhage (SAH) has not been fully illustrated. This study was designed to explore changes of expression level and potential roles and mechanisms of TRAF6 in early brain injury (EBI) after SAH using a Sprague-Dawley rat model of SAH induced in 0.3 mL non-heparinized autologous arterial blood injected into the pre-chiasmatic cistern. First, compared with the sham group, we found that the expression levels of TRAF6 increased gradually and peaked at 24 h after SAH. Second, the results showed that application of TRAF6 over-expression plasmid and genetic silencing siRNA could increase or decrease expression of TRAF6, respectively, and severely exacerbate or relieve EBI after SAH, including neuronal death, brain edema, and blood-brain barrier injury. Meanwhile, the levels of autophagy and oxidative stress were reduced and increased separately. Finally, GFP-TRAF6-C70A, which is a TRAF6 mutant that lacks E3 ubiquitin ligase activity, was used to explore the mechanism of TRAF6 in SAH, and the results showed that EBI and oxidative stress were reduced, but the levels of autophagy were increased under this condition. Collectively, these results indicated that TRAF6 affected the degree of EBI after SAH by inhibiting autophagy and promoting oxidative stress.

Perioperative time course of matrix metalloproteinase-9 (MMP-9), its tissue inhibitor TIMP-1 & S100B protein in carotid surgery

Background & objectives:

Ischaemic stroke is a life burdening disease for which carotid endarterectomy (CEA) is considered a gold standard intervention. Pro-inflammatory markers like matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) and S-100 Beta (S100B) may have a role in the early inflammation and cognitive decline following CEA. This study was aimed to describe the perioperative time courses and correlations between of MMP-9, TIMP-1 and S100B following CEA.

Methods:

Fifty four patients scheduled for CEA were enrolled. Blood samples were collected at four time points, T₁: preoperative, T₂: 60 min after cross-clamp release, T₃: first postoperative morning, T₄: third postoperative morning. Twenty atherosclerotic patients were included as controls. Plasma MMP-9, TIMP-1 and S100B levels were estimated by ELISA.

Results:

TIMP-1 was decreased significantly in the CEA group (P<0.01). Plasma MMP-9 was elevated and remained elevated from T_1-4 in the CEA group (P<0.05) with a marked elevation in T₃ compared to T₁ (P<0.05). MMP-9/TIMP-1 was elevated in the CEA group and increased further by T₂ and T₃ (P<0.05). S100B was elevated on T₂ and decreased on T_3-4 compared to T₁.

Interpretation & conclusions:

Our study provides information on the dynamic changes of MMP-9-TIMP-1 system and S100B in the perioperative period. Preoperative reduction of TIMP-1 might be predictive for shunt requirement but future studies are required for verification.

Diagnostic and Predictive Levels of Calcium-binding Protein A8 and Tumor Necrosis Factor Receptor-associated Factor 6 in Sepsis-associated Encephalopathy: A Prospective Observational Study

Background:

Despite its high prevalence, morbidity, and mortality, sepsis-associated encephalopathy (SAE) is still poorly understood. The aim of this prospective and observational study was to investigate the clinical significance of calcium-binding protein A8 (S100A8) in serum and tumor necrosis factor receptor-associated factor 6 (TRAF6) in peripheral blood mononuclear cells (PBMCs) in diagnosing SAE and predicting its prognosis.

Methods:

Data of septic patients were collected within 24 h after Intensive Care Unit admission from July 2014 to March 2015. Healthy medical personnel served as the control group. SAE was defined as cerebral dysfunction in the presence of sepsis that fulfilled the exclusion criteria. The biochemical indicators, Glasgow Coma Scale, Acute Physiology and Chronic Health Evaluation score II, TRAF6 in PBMC, serum S100A8, S100β, and neuron-specific enolase were evaluated in SAE patients afresh. TRAF6 and S100A8 were also measured in the control group.

Results:

Of the 57 enrolled patients, 29 were diagnosed with SAE. The S100A8 and TRAF6 concentrations in SAE patients were both significantly higher than that in no-encephalopathy (NE) patients, and higher in NE than that in controls (3.74 ± 3.13 vs. 1.08 ± 0.75 vs. 0.37 ± 0.14 ng/ml, P < 0.01; 3.18 ± 1.55 vs. 1.02 ± 0.63 vs. 0.47 ± 0.10, P < 0.01). S100A8 levels of 1.93 ng/ml were diagnostic of SAE with 92.90% specificity and 69.00% sensitivity in the receiver operating characteristic (ROC) curve, and the area under the curve was 0.86 (95% confidence interval [CI]: 0.76–0.95). TRAF6-relative levels of 1.44 were diagnostic of SAE with 85.70% specificity and 86.20% sensitivity, and the area under the curve was 0.94 (95% CI: 0.88–0.99). In addition, S100A8 levels of 2.41 ng/ml predicted 28-day mortality of SAE with 90.00% specificity and 73.70% sensitivity in the ROC curve, and the area under the curve was 0.88. TRAF6 relative levels of 2.94 predicted 28-day mortality of SAE with 80.00% specificity and 68.40% sensitivity, and the area under the curve was 0.77. Compared with TRAF6, the specificity of serum S100A8 in diagnosing SAE and predicting mortality was higher, although the sensitivity was low. In contrast, the TRAF6 had higher sensitivity for diagnosis.

Conclusions:

Peripheral blood levels of S100A8 and TRAF6 in SAE patients were elevated and might be related to the severity of SAE and predict the outcome of SAE. The efficacy and specificity of S100A8 for SAE diagnosis were superior, despite its weak sensitivity. S100A8 might be a better biomarker for diagnosis of SAE and predicting prognosis.

Ulinastatin downregulates TLR4 and NF-kB expression and protects mouse brains against ischemia/reperfusion injury

BACKGROUND

Inflammatory damage plays an important role in ischemic stroke and provides potential targets for therapy. Ulinastatin (UTI), a drug used to treat shock and acute pancreatitis in clinic, has attracted attention for its protective effects through immunomodulatory and anti-inflammatory properties. However, the effect of UTI in the acute phase of cerebral ischemia/reperfusion (I/R) is not clear. This study is to investigate the potential neuroprotective effect of UTI and explore its underlying mechanisms.

METHODS

Male CD-1 mice were subjected to transient middle cerebral artery occlusion (tMCAO) and randomly assigned into four groups: Sham (sham-operated) group, tMCAO (tMCAO + 0.9% saline) group, UTI-L (tMCAO + UTI 1500 U/100 g), and UTI-H (tMCAO + UTI 3000 U/100 g) group. UTI was administered immediately after reperfusion in the UTI-L and UTI-H groups. About 24 h after the reperfusion, the neurological deficit, brain water content, and infarct volume were detected. Immunohistochemistry, western blot and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to detect the expression of TLR4 and NF-κB in the ischemic cerebral cortex.

RESULTS

Compared with tMCAO group, both UTI-L and UTI-H groups dramatically ameliorated neurological deficit (p < 0.05), lessened the brain water content (p < 0.05) and infarct volume (p < 0.05), and decreased the expression of TLR4 and NF-κB.

CONCLUSION

These results showed that UTI protected the brain against ischemic injury which may be due to the alleviation of inflammation reaction in early stage through downregulating TLR4 and NF-κB expression.

Toll-like Receptors in the Vascular System: Sensing the Dangers Within

Toll-like receptors (TLRs) are components of the innate immune system that respond to exogenous infectious ligands (pathogen-associated molecular patterns, PAMPs) and endogenous molecules that are released during host tissue injury/death (damage-associated molecular patterns, DAMPs). Interaction of TLRs with their ligands leads to activation of downstream signaling pathways that induce an immune response by producing inflammatory cytokines, type I interferons (IFN), and other inflammatory mediators. TLR activation affects vascular function and remodeling, and these molecular events prime antigen-specific adaptive immune responses. Despite the presence of TLRs in vascular cells, the exact mechanisms whereby TLR signaling affects the function of vascular tissues are largely unknown. Cardiovascular diseases are considered chronic inflammatory conditions, and accumulating data show that TLRs and the innate immune system play a determinant role in the initiation and development of cardiovascular diseases. This evidence unfolds a possibility that targeting TLRs and the innate immune system may be a novel therapeutic goal for these conditions. TLR inhibitors and agonists are already in clinical trials for inflammatory conditions such as asthma, cancer, and autoimmune diseases, but their study in the context of cardiovascular diseases is in its infancy. In this article, we review the current knowledge of TLR signaling in the cardiovascular system with an emphasis on atherosclerosis, hypertension, and cerebrovascular injury. Furthermore, we address the therapeutic potential of TLR as pharmacological targets in cardiovascular disease and consider intriguing research questions for future study.

Curcumin by down-regulating NF-kB and elevating Nrf2, reduces brain edema and neurological dysfunction after cerebral I/R

BACKGROUND

Oxidation, inflammation, and apoptosis are three critical factors for the pathogenic mechanism of cerebral ischemia/reperfusion (I/R) injury. Curcumin exhibits substantial biological properties via anti-oxidation, anti-inflammation and anti-apoptotic effects; however, the molecular mechanism underlying the effects of curcumin against cerebral I/R injury remains unclear.

OBJECTIVE

To investigate the effects of curcumin on cerebral I/R injury associated with water content, infarction volume, and the expression of nuclear factor-kappa-B (NF-κB) and nuclear factor-erythroid-related factor-2 (Nrf2).

METHODS

Middle cerebral artery occlusion (MCAO, 1-hour occlusion and 24-hour reperfusion) was performed in male Wistar rats (n=64) as a cerebral I/R injury model. In the MCAO+CUR group, the rats were administered curcumin (300mg/kg BW, i.p.) at 30min after occlusion. The same surgical procedures were performed in SHAM rats without MCAO occlusion. At 24h post-operation, the parameters, including neurological deficit scores, blood brain barrier (BBB) disruption, water content, and infarction volume, were determined. Brain tissue NF-κB and Nrf2 expression levels were assayed through immunohistochemistry.

RESULTS

Compared with the SHAM group, BBB disruption, neurological deficit, and increased brain water content and infarction volume were markedly demonstrated in the MCAO group. NF-κB expression was enhanced in the MCAO group. However, in the MCAO+CUR group, the upregulation of Nrf2, an anti-oxidation related protein, was consistent with a significant decline in the water content, infarction volume, and NF-κB expression.

CONCLUSION

The protective effects of curcumin against cerebral I/R injury reflect anti-oxidation, anti-inflammation and anti-apoptotic activities, resulting in the elevation of Nrf2 and down-regulation of NF-κB.

Cinnamaldehyde inhibits inflammation and brain damage in a mouse model of permanent cerebral ischaemia

BACKGROUND AND PURPOSE

Recent findings suggest the importance of inflammation in the pathogenesis of cerebral ischaemia and its potential as a therapeutic target. Cinnamaldehyde is a diterpene with a wide range of anti-inflammatory effects thus may be advantageous in the treatment of cerebral ischaemia. The present study examined the potential therapeutic effects of cinnamaldehyde on cerebral ischaemia using a mouse model with permanent middle cerebral artery occlusion.

EXPERIMENTAL APPROACH

Male CD-1 mice, which had the middle cerebral artery occluded, were treated (i.p.) with cinnamaldehyde. Neuroprotection by cinnamaldehyde was analysed by evaluating neurological deficit scores, brain oedema and infarct volume. Expressions of signal transduction molecules and inflammatory mediators were measured by Western blotting, qRT-PCR and immunohistochemical staining. Activation of NF-κB was assessed by Western blotting, immunohistochemistry and immunofluorescence.

KEY RESULTS

Cinnamaldehyde reduced the neurological deficit scores, brain oedema and infarct volume. Cinnamaldehyde suppressed the activation of signal transduction molecules including toll-like receptor 4, tumour necrosis receptor-associated factor 6 and NF-κB, attenuated the increased levels of TNF-α, IL-1β, CCL2 and endothelial-leukocyte adhesion molecule-1 and ultimately reduced leukocyte infiltration into the ischaemic brain areas after cerebral ischaemia.

CONCLUSIONS AND IMPLICATIONS

Cinnamaldehyde protects against cerebral ischaemia injury by inhibiting inflammation, partly mediated by reducing the expression of toll-like receptor 4, tumour necrosis receptor-associated factor 6 and the nuclear translocation of NF-κB. Our findings suggest that cinnamaldehyde may serve as a new candidate for further development as a treatment for stroke.

Puerarin protects brain tissue against cerebral ischemia/reperfusion injury by inhibiting the inflammatory response

Puerarin, a traditional Chinese medicine, exerts a powerful neuroprotective effect in cerebral ischemia/reperfusion injury, but its mechanism is unknown. Here, we established rat models of middle cerebral artery ischemia/reperfusion injury using the suture method. Puerarin (100 mg/kg) was administered intraperitoneally 30 minutes before middle cerebral artery occlusion and 8 hours after reperfusion. Twenty-four hours after reperfusion, we found that puerarin significantly improved neurological deficit, reduced infarct size and brain water content, and notably diminished the expression of Toll-like receptor-4, myeloid differentiation factor 88, nuclear factor kappa B and tumor necrosis factor-α in the ischemic region. These data indicate that puerarin exerts an anti-inflammatory protective effect on brain tissue with ischemia/reperfusion damage by downregulating the expression of multiple inflammatory factors.

Neuroprotective effects of rhynchophylline against ischemic brain injury via regulation of the Akt/mTOR and TLRs signaling pathways

Rhynchophylline (Rhy) is an alkaloid isolated from Uncaria which has long been recommended for the treatment of central nervous diseases. In our study, the neuroprotective effect of Rhy was investigated in a stroke model, namely permanent middle cerebral artery occlusion (pMCAO). Rats were injected intraperitoneally once daily for four consecutive days before surgery and then received one more injection after surgery. The protein and mRNA levels of p-Akt, p-mTOR, apoptosis-related proteins (p-BAD and cleaved caspase-3), TLR2/4/9, NF-κB, MyD88, BDNF and claudin-5 were examined. Following pMCAO, Rhy treatment not only ameliorated neurological deficits, infarct volume and brain edema, but also increased claudin-5 and BDNF expressions (p < 0.05). Moreover, Rhy could activate PI3K/Akt/mTOR signaling while inhibiting TLRs/NF-κB pathway. Wortmannin, a selective PI3K inhibitor, could abolish the neuroprotective effect of Rhy and reverse the increment in p-Akt, p-mTOR and p-BAD levels. In conclusion, we hypothesize that Rhy protected against ischemic damage, probably via regulating the Akt/mTOR pathway.

Bicyclol upregulates transcription factor Nrf2, HO-1 expression and protects rat brains against focal ischemia

Oxidative damage plays a detrimental role in the pathophysiology of cerebral ischemia and may represent a therapeutic target. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) controls the coordinated expression of the important antioxidant and detoxification genes through a promotor sequence termed the antioxidant response element. Bicyclol has been proved to elicit a variety of biological effects through its antioxidant and anti-inflammatory properties. But the underlying mechanisms are poorly understood. In this study, the role of bicyclol in cerebral ischemia and its potential mechanism were investigated.

METHODS

Male Sprague-Dawley rats were randomly assigned to five groups: MCAO (middle cerebral artery occlusion), Vehicle (MCAO+0.5% sodium carboxymethylcellulose), By-L (Vehicle+bicyclol 50mg/kg), By-H (Vehicle+bicyclol 100mg/kg) and Sham operated groups. Bicyclol was administered intragastrically once a day for 3 consecutive days; after 1h of bicyclol pretreatment on the third day, rat ischemic stroke was induced by MCAO. Neurological deficit, infarct volume, and brain edema were detected at 24h after stroke. Western blot and RT-qPCR were used to measure the expression of Nrf2, HO-1 and SOD1. MDA was detected by the spectrophotometer.

RESULTS

Compared with MCAO group, By-H group significantly ameliorated neurological deficit, lessened the infarct volume and brain edema, increased the expression of Nrf2, HO-1 and SOD1 (P<0.05), and decreased the content of MDA (P<0.05).

CONCLUSIONS

Bicyclol protected the rat brain from ischemic damage caused by MCAO, and this effect may be through the upregulation of the transcription factor Nrf2 expression.