Ischemic Brain Injury In Rats Research Articles

The effects of Cordyceps polysaccharides on ischemic brain injury in rats via intervening with IL-23/IL-17 axis and the intestinal barrier

Cordyceps polysaccharide (CSP) has been shown to exhibit anti-inflammatory and antioxidant effects, with potential applications in ischemic stroke. This work is to explore the interventional potential of CSP in MCAO rats and the effects on the intestinal and cerebral IL-23/IL-17 axis. We conducted pharmacological experiments and mechanism exploration in MCAO rats. Our research showed that CSP improved the neurological function and cerebral pathological morphology, reduced cerebral infarction volume and water content in MCAO rats. We also found that CSP significantly decreased the IL-β, TNF-α and IL-6 in the ischemic brain and enhanced the ability of MCAO rats to resist oxidative stress. Additionally, CSP improved intestinal barrier, inhibited the activation of the TLR4/Myd88/NF-κβ signaling pathway and IL-23/IL-17 axis. The study results demonstrated the effectiveness of CSP in interfering with MCAO rats. The mechanism appears to be related to protecting the intestinal barrier and inhibiting the IL-23/IL-17 axis.

Targeting inflammation and oxidative stress for protection against ischemic brain injury in rats using cupressuflavone

Inflammatory responses and oxidative stress contribute to the pathogenesis of brain ischemia/reperfusion (IR) injury. Naturally occurring bioflavonoids possess antioxidant and anti-inflammatory properties. The phytochemicals of Juniperus sabina L., known as “Abhal” in Saudi Arabia, have been studied and cupressuflavone (CUP) has been isolated as the major bioflavonoid. This study aimed to investigate the neuroprotective potential of CUP in reducing brain IR damage in rats and to understand probable mechanisms. After 60 min of inducing cerebral ischemia by closing the left common carotid artery (CCA), blood flow was restored to allow reperfusion. The same surgical procedure was performed on sham-operated control rats, excluding cerebral IR. CUP or vehicle was given orally to rats for 3 days prior to ischemia induction and for a further 3 days following reperfusion. Based on the findings of this study, compared to the IR control group, CUP-administered group demonstrated reduced neurological deficits, improved motor coordination, balance, and locomotor activity. Additionally, brain homogenates of IR rats showed a decrease in malondialdehyde (MDA) level, an increase in reduced glutathione (GSH) content, and an increase in catalase (CAT) enzyme activity following CUP treatment. CUP suppressed neuro-inflammation via reducing serum inflammatory cytokine levels, particularly those of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) and enhancing the inflammatory cytokine levels, such as Nuclear factor kappa- B (NF-κB), TANK-binding kinase-1 (TBK1), and interferon beta (IFN-β) in brain tissues. Furthermore, CUP ameliorated the histological alterations in the brain tissues of IR rats. CUP significantly suppressed caspase-3 expression and downregulated the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway as a result of suppressing High mobility group box 1 (HMGB1). To our knowledge, this is the first study to document the neuroprotective properties of CUP. Thus, the study findings revealed that CUP ameliorates IR–induced cerebral injury possibly by enhancing brain antioxidant contents, reducing serum inflammatory cytokine levels, potentiating the brain contents of TBK1 and IFN-β and suppressing the HMGB1/TLR-4 signaling pathway. Hence, CUP may serve as a potential preventive and therapeutic alternative for cerebral stroke.

Efficacy of curculigoside in protecting against ischemic brain injury through regulation of oxidative stress and NF-κB and PI3K/Akt expression

Ethnopharmacological relevanceThe ancient Chinese medicine book “Huangdi Neijing” reports that “the brain is the sea of marrow” and that the kidney “mainly induces bones to produce marrow”. Therefore, Chinese medicine has a “kidney-brain axis” theory, but supporting evidence is lacking. In this study, curculigoside, the main component of the kidney-tonifying drug Rhizoma Curculiginis, was used to explore whether a kidney-tonifying drug could regulate the pathological state of the brain. Aim of the studyTo explore the efficacy of curculigoside in protecting against ischemic brain injury (IBI) through the regulation of oxidative stress and NF-κB and PI3K/Akt expression. Materials and methodsMiddle cerebral artery occlusion (MCAO) was used to induce IBI in rats, and curculigoside was administered. The degree of IBI, morphological changes and severity of nerve injury (using neurological severity scores; NSSs) in the rats were assessed. Enzyme-linked immunosorbent assays (ELISAs), Western blotting, and immunohistochemistry were used to evaluate changes in hydrogen peroxide (H2O2), nitric oxide (NO), malondialdehyde (MDA), TNF-α, IL-1β, catalase (CAT), superoxide dismutase (SOD), nitric oxide synthase (NOS), NF-κB, PI3K and Akt levels. ResultsCurculigoside significantly alleviated behavioral deficits and reduced the degree of cerebral ischemia in the rats. After curculigoside treatment, the levels of H2O2, NO, MDA, NOS, iNOS, TNF-α, IL-1β, intercellular adhesion molecule-1 (ICAM-1) and NF-κB in the ischemic area of the brain were significantly reduced. The activities of CAT, SOD, PI3K and Akt were significantly increased. ConclusionCurculigoside is a potentially effective drug for the treatment of IBI.

Sevoflurane up-regulates miR-7a to protect against ischemic brain injury in rats by down-regulating ATG7 and reducing neuronal autophagy

The current study aimed to elucidate the effects of Sevoflurane on neuronal autophagy and ischemic brain injury by regulating miR-7a/ATG7 axis. The rat model of middle cerebral artery occlusion (MCAO) was established by thread embolization. The expression pattern of microRNA-7a (miR-7a) and autophagy-related gene 7 (ATG7) was subsequently determined in Sevoflurane-treated MCAO rats with their relation and effects on neuronal autophagy and ischemic brain injury further analyzed. Bioinformatics analysis confirmed that miR-7a could target to inhibit ATG7 in ischemic brain injury samples. Sevoflurane could alleviate ischemic brain injury in rats by reducing the level of neuronal autophagy-related factors. The expression of miR-7a was up-regulated and ATG7 was down-regulated in the brain tissues of MCAO rats after Sevoflurane treatment. ATG7 was found to induce neuronal autophagy during autophagy in the brain tissues of MCAO rats. In summary, Sevoflurane exerts protective effects on ischemic brain injury via inhibiting autophagy of neurons and microglia through the miR-7a-mediated downregulation of ATG7.

Inhibition of Sonic Hedgehog signaling inhibits fibrous scar formation and adversely affects functional outcome after ischemic brain injury in rats

To investigate the effects of inhibiting Sonic Hedgehog (Shh) signaling on fibrous scar formation and functional outcome after ischemic brain injury. Adult SD rats were randomized into sham-operated group, middle cerebral artery occlusion (MCAO) and reperfusion (I/R) group, I/R with intraventricular empty adenoviral vector (rAd-NC) injection group, and I/R with adenovirus-mediated Shh knockdown (rAd-ShShh) group. After the treatments, the neurological deficits of the rats were assessed, and the protein and mRNA expressions of fibronectin (Fn), α-SMA, and Shh in the ischemic hemisphere were detected with immunofluorescence assay and qPCR; TUNEL staining was used for detecting neural cell apoptosis. In the cell experiment, primary meningeal fibroblasts isolated from neonatal SD rats were pretreated for 24 h with TGF-β1 or TGF-β1 plus cyclopamine (CYC) before oxygen-glucose deprivation for 150 min followed by reoxygenation for 72 h (OGD/R). CCK-8 assay and scratch test were performed to examine the changes in cell proliferation and migration, and immunofluorescence assay, qPCR and Western blotting were used for detecting cell transformation and the expressions of Shh, α-SMA, and Fn. Cerebral I/R injury significantly increased the protein and mRNA expressions of Shh, α-SMA, and Fn in the ischemic hemisphere of the rats, but their expression levels were significantly lowered by intraventricular injection of rAd-Shshh (P < 0.05), which obviously increased cell apoptosis in the ischemic hemisphere (P < 0.05) and improved modified mNSS and modified Bederson scores of the rats (P < 0.05). In the cell experiment, pretreatment with TGF-β1 and TGF-β1+CYC both increased the viability of the primary meningeal fibroblasts after OGD/R. TGF-β1 significantly enhanced the migration ability and induced obvious transformation of the exposed cells (P < 0.05), but these effects were significantly attenuated by co-treatment with CYC (P < 0.05). The expressions of Shh, α-SMA and Fn in the TGF-β1 group were all significantly higher in TGF-β1-treated cells (P < 0.05) and were obviously lowered by co-treatment with CYC (P < 0.05). Inhibition of Shh signaling may inhibit fibrous scar formation and functional recovery in rats after ischemic brain injury.

The Temporal Profile of OPG Expression and Regulatory Role on Ischemic Brain Injury in Rats After MCAo

Objective To investigate the temporal profile of osteoprotegerin (OPG) in middle cerebral artery occlusion (MCAo) rats and the serum level of RANKL and ALP in OPG deficient and wild type rats. Methods Rats was anesthetized and subjected to MCAo by transient occlusion of middle cerebral artery occlusion. The serum level of OPG, RANKL and ALP in rats after MCAo was examined by ELISA assay. The protein expression of OPG in ischemic brain was determined by Western blot analysis. Results The level of OPG in the rat serum was significantly increased from 6 h after MCAo and peaked at 12-24 and 72-168 h. The protein expression of OPG was upregulated from 12 h after MCAo and peaked at 72 h. The level of RANKL and ALP was significantly decreased in OPG deficient rats after MCAo. Conclusion OPG/RANKL signaling is associated with brain injury after MCAo, indicating a potential therapeutic target for ischemic stroke.

Combination of Scalp Acupuncture with Exercise Therapy Effectively Counteracts Ischemic Brain Injury in Rats

BackgroundStroke is one of the leading causes of death and disability worldwide. Scalp acupuncture and exercise therapy have been proven as two effective methods for the treatment of stroke. However, their combined action and mechanisms have not been fully elucidated. The present study aimed to investigate the protective effect of scalp acupuncture combined with exercise therapy on neurons in rats with ischemic brain injury. Methods100 rats were randomly divided into 5 groups including sham group, model group, acupuncture group, rehabilitation group, and experimental group (scalp acupuncture combined with exercise therapy). Middle cerebral artery occlusion (MCAO) model in rats was established according to Longa modified suture method to mimic ischemic stroke. The modified Bedexer's neurological function score was used to evaluate the neurological deficits of rats and the brain infarct volume was measured using 2, 3, 5-triphenyl tetrazolium chloride monohydrate (TTC) staining. Moreover, the apoptosis in the hippocampus was detected by western blotting and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The pro-inflammatory cytokines such as interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α), reactive oxygen species (ROS) and superoxide dismutase (SOD) were determined by corresponding kits. Immunohistochemistry or immunofluorescence was performed to detect the expression of brain-derived neurotrophic factor (BDNF), S100β and glial fibrillary acidic protein (GFAP) in the hippocampi of rats. ResultsThe neurological deficit score, the expression levels of apoptotic factors such as cleaved caspase-3 and Bax, and the TUNEL-positive cell rate of the experimental group were significantly lower than those of the acupuncture group and the rehabilitation group. However, apoptosis inhibitor Bcl-2 showed downregulated expression in the MCAO model rats but this trend was reverted by single and combinatorial treatments. In addition, the contents of TNF-α, IL-1β and ROS in the acupuncture group and the rehabilitation group were significantly lower than those in the model group, but higher than the experimental group. While the opposite results were obtained in SOD activity. Furthermore, compared with the model group, the ratios of BDNF, S100β, and GFAP-positive cells in the acupuncture, rehabilitation and experimental groups were significantly increased, and the highest ratios were recorded in the experimental group. ConclusionsThis study demonstrated that scalp acupuncture combined with exercise therapy effectively counteracts ischemic brain injury via the downregulation of pro-inflammatory mediators and ROS, the increased production of the antioxidant enzyme SOD, neurotrophic factor BDNF and astrocyte activities.

Pannexin1 Channel Inhibitor (10panx) Protects Against Transient Focal Cerebral Ischemic Injury by Inhibiting RIP3 Expression and Inflammatory Response in Rats

Background: Recent studies have demonstrated that programmed necrosis (necroptosis) is a delayed component of ischemic neuronal injury and our previous study has shown that pannexin 1 channel is involved in cerebral ischemic injury and cellular inflammatory response. Here, we examined whether the pannexin 1 channel inhibitor, 10panx, could reduce focal ischemic brain injury in rats by inhibiting cellular necroptosis and the associated inflammation. Male Sprague–Dawley rats were randomly divided into sham-operated, MCAO (transient middle cerebral artery occlusion) group, and 10panx-treated groups. We investigated the effect of 10panx by assessing infarct volume and neurological deficit. Further, we determined the potential mechanism using immunofluorescent staining, Western blotting, enzyme-linked immunosorbent assay (ELISA) and TUNEL assay. We demonstrated that 10panx reduced infarct volume and alleviated neurological deficit in the MCAO injury model. 10panx ameliorated post-ischemic neuronal death, but it did not reduce the TUNEL positive neurons and expression of cleaved-caspase3. In contrast, expression of necroptosis related protein receptor-interacting protein 3 (RIP3) was significantly decreased. Furthermore, 10panx reduced the release of high mobility group box 1 (HMGB1) from neurons and inhibited microglial activation and secretion of pro-inflammatory factors. Immunent co-labeling of RIP3 with HMGB1 showed that RIP3 protein was closely related with the release of HMGB1 from nucleus to cytoplasm. Our data suggested that 10panx treatment may ameliorate MCAO injury by reducing RIP3-mediated necroptosis, HMGB1 release and associated inflammatory response. RIP3 may play an important role in the release of HMGB1 and inflammation after stroke.

Effect of branched chain amino acid on apoptosis of neurons after focal cerebral ischemia in rats

Objective To investigate the regulatory effect of branched chain amino acids(BCAA) on the expression of apoptosis related proteins after cerebral ischemia reperfusion injury and the protective effects of BCAA on ischemic brain injury in rats. Methods 40 male SD rats were randomly divided into normal diet group(n=20)and branched chain amino acid (BCAA) group(n=20)according to the random number table, and each group was randomly divided into control group (n=6), sham operation group (n=6) and model group (n=8) which used suture method to make ischemia reperfusion model. After modeling, modified Neurological Severity Scores (mNSS) was used to access the neurological impairment degree of 2, 6, 24, 48 and 72 h in each group. The expression of apoptosis related proteins (Cleaved, Bax/Bcl-2) after 72 h was detected by the method of immune protein imprinting (Caspase3) and compared between normal diet group and BCAA group. Results Compared with the normal diet rats, the mNSS of BCAA diet rats after modeling at 2, 6, 24, 48, 72 h decreased(11.35±2.78 vs. 7.15±2.41, P=0.019; 9.35±1.75 vs. 5.82±1.17, P=0.002; 6.11±1.16 vs. 4.39±1.46, P=0.048; 5.87±1.32 vs. 3.55±1.94, P=0.036; 4.98±2.24 vs. 2.09±1.33, P=0.022). The expression of cleaved caspase3 protein and the ratio of Bax/Bcl-2 decreased in BCAA group. Conclusion BCAA can alleviate the apoptosis of rats after ischemia and reperfusion, reduce the damage of nerve function, and has a positive protective effect on ischemic brain injury. Key words: Branched chain amino acid; Cerebral ischemia reperfusion; Apoptosis

Downregulation of microRNA-196a attenuates ischemic brain injury in rats by directly targeting HMGA1.

Dysfunction of the microRNA (miRNA) network is a major regulator in neurological diseases. However, little is known about the functional significance of miRs in ischemic brain injury. This study was designed to investigate the functional behaviors and regulatory mechanisms of miR-196a in ischemic brain injury. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in rats. The expression levels of miR-196a and HMGA1 were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), Western blotting, and/or immunocytochemistry. The role of miR-196a in cerebral infarction and brain cell apoptosis was determined by infarct volume estimation and Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assay, respectively. Bioinformatics software and Luciferase analysis were used to predict and confirm the targets of miR-196a. The results showed that the miR-196a expression was significantly increased in rat brain after MCAO and in cultured neonatal rat cortical neurons after oxygen-glucose deprivation (OGD). Pretreatment with antagomiR-196a by intracerebroventricular markedly reduced the miR-196a mRNA and HMGA1 protein of the brain in rats subjected to MCAO. Notably, the knockdown of miR-196a could protect MCAO rats against cerebral infarction and brain cell apoptosis. In the OGD model, apoptosis and miR-196a expressions were inhibited, while High-Mobility-Group-A1 (HMGA1) levels were increased in cortical neurons in a time-dependent manner. Moreover, HMGA1 was the target gene of miR-196a. MiR-196a overexpression promoted OGD-induced cortical neurons apoptosis possibly through negative regulation of HMGA1. These findings indicated a crucial role of miR-196a in regulating infarct volume and neuronal cell death under cerebral ischemia, thus offering a new target for the development of therapeutic agents against ischemic brain injury.

Targeted delivery of intranasally administered nanoparticles-mediated neuroprotective peptide NR2B9c to brain and neuron for treatment of ischemic stroke

The lack of effective therapies mandates the development of new treatment strategies for ischemic stroke. The NR2B9c peptide can prevent N-Methyl-D-aspartate receptor (NMDAR)-mediated neurotoxicity induced by ischemia without affecting essential NMDAR activity and brings hope for stroke therapy. However, it is very difficult for NR2B9c to cross by itself the blood–brain barrier (BBB) and the neuron membrane. To provide a suitable delivery for unleashing the therapeutic potential of NR2B9c, in consideration of a high affinity of wheat germ agglutinin (WGA) for WGA receptors abundantly present on olfactory epithelium and neuronal surface, we developed WGA-modified nanoparticles carrying NR2B9c (NR2B9c-WGA-NPs). Following intranasal administration, NR2B9c-WGA-NPs are able to bypass the BBB and effectively transport NR2B9c into the brain and neuron, and therefore can protect neurons against excitotoxicity, reduce ischemic brain injury in rats and ameliorate their neurological function deficits. The intranasal administration of NR2B9c-WGA-NPs may serve as a practical stroke therapy.

Sevoflurane reduces ischemic brain injury in rats with diet and streptozotocin-induced diabetes

To investigate the role of S100B, oxidative stress and the apoptosis signaling pathways in the sevoflurane induced neuroprotective effect on stroke. The brain injury, molecular and cellular damage, and functional recovery were investigated upon ischemic brain injury followed by sevoflurane treatment. Longa rodent stroke scales was used to quantify neurological deficits. TTC staining was used to measure infarct volume of brain tissue. Absolute brain water content was measured by wet/dry weight method. The neuronal morphological change was assessed by H and E staining. The spatial learning and memory ability were measured by water maze test. Serum proteins including S100B, GSH-PX, SOD, Bcl-2, Bax, Caspase-3 were measured by ELISA. The level of NOS and NO in serum was determined by colorimetric method. Compared with control, the serum proteins including S100B, Bax, NO, Caspase-3, and NOS activity in cerebral infarction rats increased significantly while SOD, GSH-PX, and Bcl-2 decreased significantly. Diabetic mellitus complicated with cerebral infarction rats showed more dramatic increase for S100B, Bax, NO, Caspase-3, and NOS activity and dramatic decrease for SOD, GSH-PX, and Bcl-2. Interestingly, sevoflurane reduced the changes significantly. The S100B level positively correlated with brain damage, NO, Bax, caspase-3, and NOS activity but negatively correlated with SOD, Bax, and GSH-PX. Brain damage in sevoflurane groups decreased while behavior outcomes including Longa neurologic score, learning, and memory increased significantly. The neuroprotective effect of sevoflurane is associated with defense mechanisms against free radical-induced oxidative stress and inhibition of apoptosis. S100B protein correlated with oxidative stress and the apoptosis signaling pathways.

Synergistic Interaction Between Zinc and Reactive Oxygen Species Amplifies Ischemic Brain Injury in Rats.

Background and Purpose- Although intracellular zinc accumulation has been shown to contribute to neuronal death after cerebral ischemia, the mechanism by which zinc keeps on accumulating to cause severe brain damage remains unclear. Herein the dynamic cause-effect relationships between zinc accumulation and reactive oxygen species (ROS) production during cerebral ischemia/reperfusion are investigated. Methods- Rats were treated with zinc chelator, ROS scavenger, mitochondria-targeted ROS inhibitor, or NADPH oxidase inhibitor during a 90-minute middle cerebral artery occlusion. Cytosolic labile zinc, ROS level, cerebral infarct volume, and neurological functions were assessed after ischemia/reperfusion. Results- Zinc and ROS were colocalized in neurons, leading to neuronal apoptotic death. Chelating zinc reduced ROS production at 6 and 24 hours after reperfusion, whereas eliminating ROS reduced zinc accumulation only at 24 hours. Furthermore, suppression of mitochondrial ROS production reduced the total ROS level and brain damage at 6 hours after reperfusion but did not change zinc accumulation, indicating that ROS is produced mainly from mitochondria during early reperfusion and the initial zinc release is upstream of ROS generation after ischemia. Suppression of NADPH oxidase decreased ROS generation, zinc accumulation, and brain damage only at 24 hours after reperfusion, indicating that the majority of ROS is produced by NADPH oxidase at later reperfusion time. Conclusions- This study provides the direct evidence that there exists a positive feedback loop between zinc accumulation and NADPH oxidase-induced ROS production, which greatly amplifies the damaging effects of both. These findings reveal that different ROS-generating source contributes to ischemia-generated ROS at different time, underscoring the critical importance of spatial and temporal factors in the interaction between ROS and zinc accumulation, and the consequent brain injury, after cerebral ischemia/reperfusion.

MiR-377 Regulates Inflammation and Angiogenesis in Rats After Cerebral Ischemic Injury.

Ischemic stroke is the leading cause of disabilities worldwide. MicroRNA-377 (miR-377) plays important roles in ischemic injury. The present study focused on the mechanisms of miR-377 in protecting ischemic brain injury in rats. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in rats. Primary rat microglial cells and brain microvascular endothelial cells (BMECs) were exposed to oxygen-glucose deprivation (OGD). The concentrations of cytokines (TNF-α, IL-1β, IL-6, IFN-γ, TGF-β, MMP2, COX2, and iNOS) in the culture medium were measured by specific ELISA. Tube formation assay was for the in vitro study of angiogenesis. Luciferase reporter assay was performed to confirm whether VEGF and EGR2 were direct targets of miR-377. The MCAO rats were intracerebroventricular (ICV) injection of miR-377 inhibitor to assess its protective effects in vivo. MiR-377 levels were decreased in the rat brain tissues at 1, 3, and 7 d after MCAO. Both microglia cells and BMECs under OGD showed markedly lower expression levels of miR-377 while higher expression levels of EGR2 and VEGF compared to those under normoxia conditions. Knockdown of miR-377 inhibited microglial activation and the release of pro-inflammatory cytokines after OGD. Suppression of miR-377 promoted the capillary-like tube formation and cell proliferation and migration of BMECs. The anti-inflammation effect of EGR2 and the angiogenesis effect of VEGF were regulated by miR-377 after OGD. Inhibition of miR-377 decreased cerebral infarct volume and suppressed cerebral inflammation but promoted angiogenesis in MCAO rats. Knockdown of miR-377 lessened the ischemic brain injury through promoting angiogenesis and suppressing cerebral inflammation. J. Cell. Biochem. 119: 327-337, 2018. © 2017 Wiley Periodicals, Inc.

Semax, an analog of ACTH(4-7), regulates expression of immune response genes during ischemic brain injury in rats.

Brain stroke continues to claim the lives of million people every year. To build the effective strategies for stroke treatment it is necessary to understand the neuroprotective mechanisms that are able to prevent the ischemic injury. Consisting of the ACTH(4-7) fragment and the tripeptide Pro-Gly-Pro (PGP), the synthetic peptide Semax effectively protects brain against ischemic stroke. However, the molecular mechanisms underlying its neuroprotection and participation of PGP in them are still needed to be clarified. To reveal biological processes and signaling pathways, which are affected by Semax and PGP, we performed the transcriptome analysis of cerebral cortex of rats with focal cerebral ischemia treated by these peptides. The genome-wide biochip data analysis detected the differentially expressed genes (DEGs) and bioinformatic web-tool Ingenuity iReport found DEGs associations with several biological processes and signaling pathways. The immune response is the process most markedly affected by the peptide: Semax enhances antigen presentation signaling pathway, intensifies the effect of ischemia on the interferon signaling pathways and affects the processes for synthesizing immunoglobulins. Semax significantly increased expression of the gene encoding the immunoglobulin heavy chain, highly affects on cytokine, stress response and ribosomal protein-encoding genes after occlusion. PGP treatment of rats with ischemia attenuates the immune activity and suppresses neurotransmission in the CNS. We suppose that neuroprotective mechanism of Semax is realized via the neuroimmune crosstalk, and the new properties of PGP were found under ischemia. Our results provided the basis for further proteomic investigations in the field of searching Semax neuroprotection mechanism.

Long-term consumption of fermented rooibos herbal tea offers neuroprotection against ischemic brain injury in rats.

Stroke is the second leading cause of death worldwide, affecting about 240 people a day in South Africa and leaving survivors with residual disabilities. At the moment, there is no clinically approved neuroprotective product for stroke but the consumption of plant polyphenols has been suggested to offer some protection against stroke. In this study, we investigated the effects of long-term consumption of fermented rooibos herbal tea (FRHT) on ischemia/reperfusion (I/R)-induced brain injury in adult male Wistar rats. FRHT was administered to the animals ad libitum for 7 weeks prior to the induction of ischemic injury via a 20-minute bilateral occlusion of the common carotid arteries (BCCAO) followed by reperfusion for 24, 96 and 168 hours respectively. Neurobehavioural deficits, brain oedema, blood-brain barrier (BBB) damage, apoptosis, lipid peroxidation and total antioxidant capacity were subsequently evaluated using standard methods. Our results showed that long-term consumption of FRHT by Wistar rats signi icantly reduced brain oedema and neuronal apoptosis, but did not attenuate BBB damage following cerebral ischemia. Analysis of whole-brain homogenates showed significantly reduced lipid peroxidation levels, increased total antioxidant capacity and resulted in improved neurobehavioural outcomes in FRHT-treated rats when compared with untreated animals. Taken together, our results tend to suggest that continuous consumption of FRHT could confer some protection against ischemic brain injury (IBI) and is therefore highly recommended for patients with stroke-predisposing conditions.

Amelioration of Ischemic Brain Injury in Rats With Human Umbilical Cord Blood Stem Cells: Mechanisms of Action.

Despite the high prevalence and devastating outcome, there remain a few options for treatment of ischemic stroke. Currently available treatments are limited by a short time window for treatment and marginal efficacy when used. We have tested a human umbilical cord blood-derived stem cell line that has been shown to result in a significant reduction in stroke infarct volume as well as improved functional recovery following stroke in the rat. In the present study we address the mechanism of action and compared the therapeutic efficacy of high- versus low-passage nonhematopoietic umbilical cord blood stem cells (nh-UCBSCs). Using the middle cerebral arterial occlusion (MCAo) model of stroke in Sprague-Dawley rats, we administered nh-UCBSC by intravenous (IV) injection 2 days following stroke induction. These human cells were injected into rats without any immune suppression, and no adverse reactions were detected. Both behavioral and histological analyses have shown that the administration of these cells reduces the infarct volume by 50% as well as improves the functional outcome of these rats following stroke for both high- and low-passaged nh-UCBSCs. Flow cytometry analysis of immune cells present in the brains of normal rats, rats with ischemic brain injury, and ischemic animals with nh-UCBSC treatment confirmed infiltration of macrophages and T cells consequent to ischemia and reduction to normal levels with nh-UCBSC treatment. Flow cytometry also revealed a restoration of normal levels of microglia in the brain following treatment. These data suggest that nh-UCBSCs may act by inhibiting immune cell migration into the brain from the periphery and possibly by inhibition of immune cell activation within the brain. nh-UCBSCs exhibit great potential for treatment of stroke, including the fact that they are associated with an increased therapeutic time window, no known ill-effects, and that they can be expanded to high numbers for, and stored for, treatment.

Neuroprotection by combination of resveratrol and enriched environment against ischemic brain injury in rats

Objectives: Both resveratrol (RV) and enriched environment (EE) exert beneficial effects on neurological functional recovery after an ischemic brain injury.Methods: The neuroprotective effect of combined treatment of RV and EE was examined in a rat model of middle cerebral artery occlusion (MCAO), aiming to further promote neurological functional recovery.Results: The combined therapy of RV and EE clearly improved locomotor activity and behaviour examination, compared to the monotherapy of RV or EE alone. Stroke severity was also markedly ameliorated by the co-treatment. Mechanistic study revealed that the combined treatment reduced oxidative stress. Moreover, the detrimental ERK1/2 signalling upregulated by MCAO injury was markedly suppressed by the co-treatment, compared to RV or EE monotherapy.Discussion: Altogether, the combined therapy of RV and EE showed a clearly enhanced neuroprotective effect, compared to RV or EE monotherapy, which might be a new strategy for the treatment of ischemic brain injury.

Effects of Sex and Mild Intrainsult Hypothermia on Neuropathology and Neural Reorganization following Neonatal Hypoxic Ischemic Brain Injury in Rats.

Hypoxia ischemia (HI) is a recognized risk factor among late-preterm infants, with HI events leading to varied neuropathology and cognitive/behavioral deficits. Studies suggest a sex difference in the incidence of HI and in the severity of subsequent behavioral deficits (with better outcomes in females). Mechanisms of a female advantage remain unknown but could involve sex-specific patterns of compensation to injury. Neuroprotective hypothermia is also used to ameliorate HI damage and attenuate behavioral deficits. Though currently prescribed only for HI in term infants, cooling has potential intrainsult applications to high-risk late-preterm infants as well. To address this important clinical issue, we conducted a study using male and female rats with a postnatal (P) day 7 HI injury induced under normothermic and hypothermic conditions. The current study reports patterns of neuropathology evident in postmortem tissue. Results showed a potent benefit of intrainsult hypothermia that was comparable for both sexes. Findings also show surprisingly different patterns of compensation in the contralateral hemisphere, with increases in hippocampal thickness in HI females contrasting reduced thickness in HI males. Findings provide a framework for future research to compare and contrast mechanisms of neuroprotection and postinjury plasticity in both sexes following a late-preterm HI insult.

Neuroplasticity for spontaneous functional recovery after neonatal hypoxic ischemic brain injury in rats observed by functional MRI and diffusion tensor imaging

For infants and children, an incredible resilience from injury is often observed. There is growing evidence that functional recovery after brain injury might well be a consequence of the reorganization of the neural network as a process of neuroplasticity. We demonstrate the presence of neuroplasticity at work in spontaneous recovery after neonatal hypoxic ischemic (HI) injury, by elucidating a precise picture in which such reorganization takes place using functional MRI techniques. For all 12 siblings, 6 rats were subjected to severe HI brain injury and 6 rats underwent sham operation only. Severe HI brain injury was induced to postnatal day 7 (p7) Sprague–Dawley rats according to the Rice–Vannucci model (right carotid artery occlusion followed by 150min of hypoxia with 8% O2 and 92% of N2). Brain activation maps along with anatomical and functional connectivity maps related to the sensory motor function were obtained at adult (p63) using blood oxygen level dependent (BOLD)-functional MRI (fMRI), resting state-functional MRI (rs-fMRI) and diffusion tensor imaging (DTI); each of these MRI data was related to sensory motor functional outcome. In-depth investigation of the functional MRI data revealed: 1) intra-hemispheric expansion of BOLD signal activation in the contralesional undamaged hemisphere for ipsilesional forepaw stimuli to include the M2 and Cg1 in addition to the S1 and M1 wide spreading in the anterior and posterior directions, 2) inter-hemispheric transfer of BOLD signal activation for contralesional forepaw stimuli, normally routed to the injured hemisphere, to analogous sites in the contralesional undamaged hemisphere, localized newly to the M1 and M2 with a reduced portion of the S1, 3) inter-hemispheric axonal disconnection and axonal rewiring within the undamaged hemisphere as shown through DTI, and 4) increased functional interactions within the cingulate gyrus in the HI injured rats as shown through rs-fMRI. The BOLD signal amplitudes as well as DTI and rs-fMRI data well correlate with behavioral tests (tape to remove). We found that function normally utilizing what would be the injured hemisphere is transferred to the uninjured hemisphere, and functionality of the uninjured hemisphere remains not untouched but is also rewired in an expansion corresponding to the newly formed sensorimotor function from both the contralesional and the ipsilesional sides. The conclusion drawn from the data in our current study is that enhanced motor function in the contralesional hemisphere governs both the normal and damaged sides, indicating that active plasticity with brain laterality was spontaneously generated to overcome functional loss and established autonomously through normal experience via modification of neural circuitry for neonatal HI injured brain.