Establishment of a pMCAO model in SD rats and screening for behavioral indicators suitable for long-term monitoring.

OBJECTIVE: This study aimed to establish a permanent middle cerebral artery occlusion (pMCAO) model in rats to simulate the pathological process of stroke patients with no reperfusion. And screen highly sensitive items that could be used to detect long-term behavioral abilities in rat of intraluminal suture models. METHOD: Established the pMCAO model then tested the rats for the bilateral asymmetry, modified neurological severity score, grid-walking, cylinder, rotating, and water maze test from week 1 to week 16. RESULTS: The infarct volume of the model rats was stable (26.72% ±1.86%). The sensorimotor test of bilateral asymmetry, grid-walking, cylinder, and mNSS test showed significant differences from week 1 to week 16 after injury. The water maze test at week 16 showed significant differences in spatial exploration and learning ability between the two groups. We confirmed that there was no significant difference between MRI and TTC staining in detecting the degree of brain injury, which facilitated the diversity of subsequent detection methods. We also confirmed that at multiple time points, grid, cylinder and water maze test were significantly positively correlated with rat brain infarct volume. CONCLUSION: They are suitable for the long-term observation of behaviors in the sequela stage of stroke in rat.

Lysophosphatidic Acid Receptor 1 Plays a Pathogenic Role in Permanent Brain Ischemic Stroke by Modulating Neuroinflammatory Responses.

Lysophosphatidic acid receptor 1 (LPA1) plays a critical role in brain injury following a transient brain ischemic stroke. However, its role in permanent brain ischemic stroke remains unknown. To address this, we investigated whether LPA1 could contribute to brain injury of mice challenged by permanent middle cerebral artery occlusion (pMCAO). A selective LPA1 antagonist (AM152) was used as a pharmacological tool for this investigation. When AM152 was given to pMCAO-challenged mice one hour after occlusion, pMCAO-induced brain damage such as brain infarction, functional neurological deficits, apoptosis, and blood-brain barrier disruption was significantly attenuated. Histological analyses demonstrated that AM152 administration attenuated microglial activation and proliferation in injured brain after pMCAO challenge. AM152 administration also attenuated abnormal neuroinflammatory responses by decreasing expression levels of pro-inflammatory cytokines while increasing expression levels of anti-inflammatory cytokines in the injured brain. As underlying effector pathways, NF-κB, MAPKs (ERK1/2, p38, and JNKs), and PI3K/Akt were found to be involved in LPA1-dependent pathogenesis. Collectively, these results demonstrate that LPA1 can contribute to brain injury by permanent ischemic stroke, along with relevant pathogenic events in an injured brain.

Palmatine, a natural alkaloid, attenuates memory deficits and neuroinflammation in mice submitted to permanent focal cerebral ischemia.

Ischemic stroke is one of the major causes of human morbidity and mortality. The pathophysiology of ischemic stroke involves complex events, including oxidative stress and inflammation, that lead to neuronal loss and cognitive deficits. Palmatine (PAL) is a naturally occurring (Coptidis rhizome) isoquinoline alkaloid that belongs to the class of protoberberines and has a wide spectrum of pharmacological and biological effects. In the present study, we evaluated the impact of Palmatine on neuronal damage, memory deficits, and inflammatory response in mice submitted to permanent focal cerebral ischemia induced by middle cerebral artery (pMCAO) occlusion. The animals were treated with Palmatine (0.2, 2 and 20 mg/kg/day, orally) or vehicle (3% Tween + saline solution) 2 h after pMCAO once daily for 3 days. Cerebral ischemia was confirmed by evaluating the infarct area (TTC staining) and neurological deficit score 24 h after pMCAO. Treatment with palmatine (2 and 20 mg/kg) reduced infarct size and neurological deficits and prevented working and aversive memory deficits in ischemic mice. Palmatine, at a dose of 2 mg/kg, had a similar effect of reducing neuroinflammation 24 h after cerebral ischemia, decreasing TNF-, iNOS, COX-2, and NF- κB immunoreactivities and preventing the activation of microglia and astrocytes. Moreover, palmatine (2 mg/kg) reduced COX-2, iNOS, and IL-1ß immunoreactivity 96 h after pMCAO. The neuroprotective properties of palmatine make it an excellent adjuvant treatment for strokes due to its inhibition of neuroinflammation.

Effects of dichloromethane extraction from Piper nigrum L. and P. longum L. on the expression of autophagy-related proteins in ischemic stroke.

Piper nigrum L. and P. longum L. are widely used in various medicinal formulations. The dichloromethane fraction of Piper nigrum L. and P. longum L. (DF) can prevent cerebral ischemic injury although the underlying mechanisms are obscure. The aim of this study was to evaluate the potential neuroprotective effects of DF on a rat model of permanent middle cerebral artery occlusion (pMCAO) and assess the molecular mechanisms. Animals were administered with DF (50, 100, and 150 mg/kg) or nimodipine (12 mg/kg) 6 h after pMCAO for 14 consecutive days via intragastric gavage. In the vitro this study identified that DF reduced neurological severity scores and improved survival rate. Results showed that DF markedly inhibited the percentage of apoptotic cells as well as neuronal autophagy and mitigated the overall neuronal and vascular damage in the ischemic region. Western blot testing showed that at the molecular level, DF significantly suppressed ischemia-induced activated expression of LC3, Beclin1, Atg12, and Atg5. Overall, our study indicated that DF attenuated neuronal autophagy by suppressing the expression of autophagy-related proteins to generate neuroprotection effect for ischemic stroke.

[Protective effect and mechanism of Ershiwuwei Zhenzhu Pills on cerebral apoplexy rats].

To study the protective effect of Ershiwuwei Zhenzhu Pills on ischemic stroke rats. Ninety 4-weeks-old SPF male SD rats were randomly divided into 6 groups(n=15):sham operation group, model group, nimodipine group(12 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills high-dose group(400 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills medium-dose group(200 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills low-dose group(100 mg·kg~(-1)).The permanent middle cerebral artery occlusion model(PMCAO) was established in the model group, nimodipine group, and Ershiwuwei Zhenzhu Pills groups by the improved thread plug method, while the sham operation group did not insert the thread plug.Nimodipine group and Ershiwuwei Zhenzhu Pills groups were given intragastric administration once a day for 24 days before the modeling operation, and once 1 hour before the modeling operation, while sham operation group and model group were given equal volumes of distilled water.The neuroethology of the surviving rats was measured; The volume of cerebral infarction in rats was measured by TTC method; The histopathology of rat brain was observed by HE method; The expression levels of tumor necrosis factor α(TNF-α),interleukin-1ß(IL-1ß),interleukin-6(IL-6),malondialdehyde(MDA),superoxide dismutase(SOD) and catalase(CAT) in serum were detected by ELISA;The mRNA expressions of Notch 1,Jagged 1,Hes 1 and Bcl-2 in rat brain were detected by RT-PCR;Western blot was used to detect the expression levels of caspase-3 protein in rat brain; the expression levels of vascular endothelial growth factor(VEGF) and CD34 positive cells in rat brain were detected by immunofluorescence.The low, medium and high dose groups of Ershiwuwei Zhenzhu Pills and nimodipine group could significantly reduce the neurobehavioral score and cerebral infarction volume of rats with permanent middle cerebral artery occlusion, reduce the morphological changes of nerve cells, decrease the expression of TNF-α,IL-1ß and IL-6 in rat serum, increase the activity of SOD and CAT,and reduce the level of MDA.Furthermore, the expression levels of Notch l, Jagged l, Hes l and Bcl-2 mRNA were significantly increased, and the expression level of caspase-3 protein was decreased.Meanwhile, the number of VEGF and CD34 positive cells increased in the treatment group.The differences were statistically significant. Ershiwuwei Zhenzhu Pills has a protective effect on ischemic stroke rats, and its mechanism may be related to anti-inflammation, anti-oxidation, promotion of nerve cell proliferation, inhibition nerve cell apoptosis and promotion of angiogenesis.

Protective effect and mechanism of Ershiwuwei Zhenzhu Pills on cerebral apoplexy rats / 中国中药杂志

To study the protective effect of Ershiwuwei Zhenzhu Pills on ischemic stroke rats. Ninety 4-weeks-old SPF male SD rats were randomly divided into 6 groups(n=15):sham operation group, model group, nimodipine group(12 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills high-dose group(400 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills medium-dose group(200 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills low-dose group(100 mg·kg~(-1)).The permanent middle cerebral artery occlusion model(PMCAO) was established in the model group, nimodipine group, and Ershiwuwei Zhenzhu Pills groups by the improved thread plug method, while the sham operation group did not insert the thread plug.Nimodipine group and Ershiwuwei Zhenzhu Pills groups were given intragastric administration once a day for 24 days before the modeling operation, and once 1 hour before the modeling operation, while sham operation group and model group were given equal volumes of distilled water.The neuroethology of the surviving rats was measured; The volume of cerebral infarction in rats was measured by TTC method; The histopathology of rat brain was observed by HE method; The expression levels of tumor necrosis factor α(TNF-α),interleukin-1β(IL-1β),interleukin-6(IL-6),malondialdehyde(MDA),superoxide dismutase(SOD) and catalase(CAT) in serum were detected by ELISA;The mRNA expressions of Notch 1,Jagged 1,Hes 1 and Bcl-2 in rat brain were detected by RT-PCR;Western blot was used to detect the expression levels of caspase-3 protein in rat brain; the expression levels of vascular endothelial growth factor(VEGF) and CD34 positive cells in rat brain were detected by immunofluorescence.The low, medium and high dose groups of Ershiwuwei Zhenzhu Pills and nimodipine group could significantly reduce the neurobehavioral score and cerebral infarction volume of rats with permanent middle cerebral artery occlusion, reduce the morphological changes of nerve cells, decrease the expression of TNF-α,IL-1β and IL-6 in rat serum, increase the activity of SOD and CAT,and reduce the level of MDA.Furthermore, the expression levels of Notch l, Jagged l, Hes l and Bcl-2 mRNA were significantly increased, and the expression level of caspase-3 protein was decreased.Meanwhile, the number of VEGF and CD34 positive cells increased in the treatment group.The differences were statistically significant. Ershiwuwei Zhenzhu Pills has a protective effect on ischemic stroke rats, and its mechanism may be related to anti-inflammation, anti-oxidation, promotion of nerve cell proliferation, inhibition nerve cell apoptosis and promotion of angiogenesis.

l-Borneol Exerted the Neuroprotective Effect by Promoting Angiogenesis Coupled With Neurogenesis via Ang1-VEGF-BDNF Pathway.

At present, Stroke is still one of the leading causes of population death worldwide and leads to disability. Traditional Chinese medicine plays an important role in the prevention or treatment of stroke. l-borneol, a traditional Chinese medicine, has been used in China to treat stroke for thousands of years. However, its mechanism of action is unclear. After cerebral ischemia, promoting angiogenesis after cerebral ischemia and providing nutrition for the infarct area is an important strategy to improve the damage in the ischemic area, but it is also essential to promote neurogenesis and replenish new neurons. Here, our research shows that l-borneol can significantly improve the neurological deficits of pMCAO model rats, reduce cerebral infarction, and improve the pathological damage of cerebral ischemia. and significantly increase serum level of Ang-1 and VEGF, and significantly decrease level of ACE and Tie2 to promote angiogenesis. PCR and WB showed the same results. Immunohistochemistry also showed that l-borneol can increase the number of CD34 positive cells, further verifying that l-borneol can play a neuroprotective effect by promoting angiogenesis after cerebral ischemia injury. In addition, l-borneol can significantly promote the expression level of VEGF, BDNF and inhibit the expression levels of TGF-ß1 and MMP9 to promote neurogenesis. The above suggests that l-borneol can promote angiogenesis coupled neurogenesis by regulating Ang1-VEGF-BDNF to play a neuroprotective effect. Molecular docking also shows that l-borneol has a very high binding rate with the above target, which further confirmed the target of l-borneol to improve cerebral ischemic injury. These results provide strong evidence for the treatment of cerebral ischemia with l-borneol and provide reference for future research.

The therapeutic effect of salidroside on rats with permanent cerebral ischemia through regulating PDK/Akt signaling pathway / 中国药理学通报

Aim To investigate the neuroprotective effect and mechanism of salidroside (Sal) on rats with permanent middle cerebral artery occlusion model (pMCAO) by regulating the PI3 K/AKT signaling pathway. Methods A total of 80 healthy adult SPF male SD rats were randomly divided into sham operation group (sham group), model group (pMCAO group), drug administration group (pMCAO + Sal group) and inhibitor group (pMCAO + Sal + YL group). After the pMCAO model rats were prepared by the line bolt method, salidroside (50 mg · kg

Dichloromethane extraction from Piper nigrum L. and P. longum L. to mitigate ischemic stroke by activating the AKT/mTOR signaling pathway to suppress autophagy.

Dichloromethane fraction (DF) of Piper nigrum L. and P. longum L. (PnL and PlL), has been found to exert a protective effect against ischemic stroke in rats. However, the regulatory mechanism exerted by PnL and PIL have not been fully elucidated. In this study, we found that DF greatly ameliorated cerebral ischemic injury in a rat model of permanent middle cerebral artery occlusion (pMCAO). The neurological score, behavioral assessment, brain infarct volume, phosphorylation of AKT (p-AKT), phosphorylation mTOR (p-mTOR), and Atg7 protein levels were determined. Additionally, we discovered that DF pretreatment reduced infarct volume, neurological score, and brain damage. Furthermore, DF therapy caused the downregulation of Atg7 and p-AKT expression, as well as the upregulation of p-mTOR expression. In conclusion, our findings indicated that DF treatment can reduce brain damage and inhibit apoptosis and autophagy by activating the Akt-mTOR signaling pathway in ischemic stroke.

Focal cerebral ischemia induces changes in oligodendrocytic tau isoforms in the damaged area.

Ischemic stroke is a major cause of death and the first leading cause of long-term disability worldwide. The only therapeutic strategy available to date is reperfusion and not all the patients are suitable for this treatment. Blood flow blockage or reduction leads to considerable brain damage, affecting both gray and white matter. The detrimental effects of ischemia have been studied extensively in the former but not in the latter. Previous reports indicate that preservation of white matter integrity reduces deleterious effect of ischemia on the brain. Oligodendrocytes are sensitive to ischemic damage, however, some reports demonstrate that oligodendrogenesis occurs after ischemia. These glial cells have a complex cytoskeletal network, including tau, that plays a key role to proper myelination. 4R-Tau/3R-Tau, which differ in the presence/absence of Exon 10, are found in oligodendrocytes; but the precise role of each isoform is not understood. Using permanent middle cerebral artery occlusion model and immunofluorescence, we demonstrate that cerebral ischemia induces an increase in 3R-Tau versus 4R-Tau in oligodendrocytes in the damaged area. In addition, cellular distribution of Tau undergoes a change after ischemia, with some oligodendrocytic processes showing positive staining for 3R-Tau. This occurs simultaneously with the amelioration of neurological damage in ischemic rats. We propose that ischemia triggers an endogenous mechanism involving 3R-Tau, that induces colonization of the ischemic damaged area by oligodendrocytes in an attempt to myelinate-injured axons. Understanding the molecular mechanism of this phenomenon could pave the way for the design of therapeutic strategies that exploit glial cells for the treatment of ischemia.

Role of rno-miR-124-3p in regulating MCT1 expression in rat brain after permanent focal cerebral ischemia.

This study aimed to assess the role of microRNAs (miRNAs) in regulating monocarboxylate transporter-1 (MCT1) expression in rat brain after permanent focal cerebral ischemia to identify a new target for early treatment of cerebral ischemia. Focal cerebral ischemia was induced by permanent middle cerebral artery occlusion (pMCAO) in rats. Morphology and protein expression levels of MCT1 were assessed by immunofluorescence and Western blotting. Using bioinformatics and double luciferase reporter assays, rno-miR-124-3p was selected as a direct target for rat MCT1. Expression of rno-miR-124-3p after pMCAO was detected. Then, rats were treated with rno-miR-124-3p agomir via lateral ventricle injection, and after 6 h or 24 h ischemia, rno-miR-124-3p expression and gene and protein expression of MCT-1 were detected by qRT-PCR and Western blotting. Brain infarction was identified by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. Results showed that pMCAO induced brain infarction and increased the expression of MCT1. The levels of rno-miR-124-3p after pMCAO were in contrast to those of MCT1 protein in ischemic region, while declined after 3, 6 and 12 h of pMCAO in ischemic penumbra. After administration of rno-miR-124-3p agomir, MCT1 mRNA and protein levels were increased after 6 h of pMCAO, while decreased after 24 h of pMCAO. Meanwhile, rno-miR-124-3p levels increased after both times. TTC staining showed treatment with rno-miR-124-3p agomir reduced brain infarction. The role of rno-miR-124-3p in regulating MCT1 was as a positive regulator after 6 h of pMCAO, while a negative regulator after 24 h of pMCAO, however, both activities had protective effects against cerebral ischemia.

Catalpol Enhances Neurogenesis And Inhibits Apoptosis Of New Neurons Via BDNF, But Not The BDNF/Trkb Pathway.

BACKGROUND: The role of catalpol in brain neurogenesis and newborn neuron survival has not been previously determined in permanent middle cerebral artery occlusion (pMCAO). METHODS: Fifty-four rats were divided into 6 groups: pMCAO (model, n=9); sham operation (NS, n=9); catalpol treatment (5 mg/kg and 10 mg/kg subgroups, n=9 each); K252a (n=9); and K252a+catalpol 5 mg/kg (n=9) with stroke. The effects of catalpol on behavior, neurogenesis surrounding the infarction ipsilateral to pMCAO, and the expression of brain-derived neurotrophic factor (BDNF) and its receptor (TrkB) were evaluated. Vehicle or, K252a (i.p.), an inhibitor of TrkB phosphorylase. RESULTS: Repeated administration of catalpol reduced neurological deficits and significantly improved neurogenesis. Catalpol increased the number of newborn immature neurons, as determined by BrdU+-Nestin+ and BrdU+-Tuj-1+ staining, and downregulated cleaved caspase 3 in Tuj-1+ cells at day 7 following stroke. Moreover, catalpol increased the protein expression of Tuj-1, MAP2, and the Bcl-2/Bax ratio, as determined using Western blot. Catalpol also significantly increased brain levels of BDNF, but not TrkB, resulting in enhanced survival of newborn neurons via inhibition of apoptosis. CONCLUSION: Catalpol may contribute to neurogenesis in infarcted brain regions and help promote the survival of newborn neurons by activating BDNF, but not BDNF/TrkB signaling.

The diabetes drug semaglutide reduces infarct size, inflammation, and apoptosis, and normalizes neurogenesis in a rat model of stroke.

Stroke is a condition with few medical treatments available. Semaglutide, a novel Glucagon-like peptide-1 (GLP-1) analogue, has been brought to the market as a treatment for diabetes. We tested the protective effects of semaglutide against middle cerebral artery occlusion injury in rats. Animals were treated with 10 nmol/kg bw ip. starting 2 h after surgery and every second day for either 1, 7, 14 or 21 days. Semaglutide-treated animals showed significantly reduced scores of neurological impairments in several motor and grip strength tasks. The cerebral infarction size was also reduced, and the loss of neurons in the hippocampal areas CA1, CA3 and the dentate gyrus was much reduced. Chronic inflammation as seen in levels of activated microglia and in the activity of the p38 MAPK - MKK - c-Jun- NF-κB p65 inflammation signaling pathway was reduced. In addition, improved growth factor signaling as shown in levels of activated ERK1 and IRS-1, and a reduction in the apoptosis signaling pathway C-raf, ERK2, Bcl-2/BAX and Caspase-3 was observed. Neurogenesis had also been normalized by the drug treatment as seen in increased neurogenesis (DCX-positive cells) in the dentate gyrus and a normalization of biomarkers for neurogenesis. In conclusion, semaglutide is a promising candidate for re-purposing as a stroke treatment.

JZL184, as a monoacylglycerol lipase inhibitor, down-regulates inflammation in a cannabinoid pathway dependent manner.

INTRODUCTION: Stroke is a prevalent disorder which is associated with several complications including inflammation. JZL-184 (JZL) inhibits arachidonic acid (AA) production and consequently results in two-arachidonoylglycerol (2-AG) accumulation. Both reduced production of AA metabolic products and increased 2-AG, the agonist of type 1 cannabinoid receptor (CB1), can result in reduced inflammation. In this study, we investigated the mechanisms of JZL in the improvement of stroke complications in mouse permanent cerebral ischemia (PPMCAO) model using AM251, the antagonist of CB1. MATERIAL AND METHODS: PMCAO mice were divided into six groups including intact, controls, vehicle, JZL, AM251 and JZL plus AM251 administrated groups. Brain infarction and edema, brain levels of matrix metalloperoteinase-9 (MMP9), interleukin (IL)-10 and tumor necrosis factor-α (TNF-α) and behavioral functions have been examined in all groups. RESULTS: The results showed that JZL lowered brain infarction, neurological disorders, TNF-α and MMP9 more effectively than JZL plus AM251. JZL and JZL plus AM251 reduced brain edema and increased brain IL-10. JZL, AM251 and JZL plus AM251 improve behavioral functions. DISCUSSION: JZL reduces brain infarction and brain pro-inflammatory molecules in CB1 pathway dependent manner. JZL also reduces brain edema and increased IL-10 in CB1 pathways or decreased AA metabolites. Further, AM251 improves behavioral functions via unknown mechanisms.

The protective roles of L-borneolum, D-borneolum and synthetic borneol in cerebral ischaemia via modulation of the neurovascular unit.

OBJECTIVE: Borneol has been used to treat stroke in China since ancient times. In our previous research, we demonstrated the effect of borneol on cerebral ischaemia injury via meta-analysis. The neurovascular unit (NVU) is the structural basis of the preservation of the brain microenvironment and is believed to be a promising target in treating stroke. In this research, we explored the roles of three kinds of borneol, namely, L-borneolum (B1), D-borneolum (B2) and synthetic borneol (B3), in the NVU with permanent middle cerebral artery occluded (pMCAO) rats. METHODS: The Longa scoring method was used to evaluate nerve function deficits in the pMCAO rats. Awakening time, brain water content, brain index and brain edema rate were also measured. TTC staining was used to calculate the cerebral infarction rate. The morphology of the ischaemia penumbra brain tissue was observed via HE staining, and the neuronal denatured cell index (DCI) was calculated. An enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of vascular endothelial growth factor VEGF and TNF-α in the serum. Moreover, the ultrastructures of the neurons and of the blood-brain barrier (BBB) were observed using transmission electron microscopy. The expression levels of Claudin-5, Bcl-2 and Bax in the ischaemia penumbra of pMCAO rats were detected using real-time PCR and immunohistochemistry. RESULTS: Pretreatment with B1, B2 and B3 delayed the recovery time (P < 0.01). B1 remarkably ameliorated neurological deficits 24 h after cerebral ischaemia (P < 0.05). Moreover, B1 and B3 were both able to ameliorate brain edema and the area of cerebral infarction. In addition, B1, B2 and B3 all increased serum VEGF levels and decreased serum TNF-α levels (P < 0.01). For the ultrastructure determination, the BBB and the nerve centre were significantly improved by B1, B2 and B3. The mechanistic exploration revealed that B2 and B3 protected the brain by reducing the Bax/Bcl-2 ratio (P < 0.05, P < 0.01, respectively). Immunohistochemistry suggested that B1, B2 and B3 could also enhance the expression of Claudin-5 (P < 0.01). CONCLUSION: The three kinds of borneol demonstrated different protective effects on cerebral ischaemia injury. L-Borneolum displayed the most prominent anti-cerebral ischaemia effect among them. The mechanism was most likely executed via anti-apoptosis and anti-inflammation effects and maintenance of the stability of the BBB and TJs to comprehensively improve NVU function.

Time-course investigation of blood-brain barrier permeability and tight junction protein changes in a rat model of permanent focal ischemia.

Permanent middle cerebral artery occlusion (pMCAO) is an animal model that is widely used to simulate human ischemic stroke. However, the timing of the changes in the expression of tight junction (TJ) proteins and synaptic proteins associated with pMCAO remain incompletely understood. Therefore, to further explore the characteristics and mechanisms of blood-brain barrier (BBB) damage during cerebral ischemic stroke, we used a pMCAO rat model to define dynamic changes in BBB permeability within 120 h after ischemia in order to examine the expression levels of the TJ proteins claudin-5 and occludin and the synaptic proteins synaptophysin (SYP) and postsynaptic density protein 95 (PSD95). In our study, Evans blue content began to increase at 4 h and was highest at 8 and 120 h after ischemia. TTC staining showed that cerebral infarction was observed at 4 h and that the percentage of infarct volume increased with time after ischemia. The expression levels of claudin-5 and occludin began to decline at 1 h and were lowest at 8 and 120 h after ischemia. The expression levels of SYP and PSD95 decreased from 12 to 120 h after ischemia. GFAP, an astrocyte marker, gradually increased in the cortex penumbra over time post-ischemia. Our study helps clarify the characteristics of pMCAO models and provides evidence supporting the translational potential of animal stroke models.

Temporal remodeling of pial collaterals and functional deficits in a murine model of ischemic stroke.

BACKGROUND: Leptomeningeal anastomoses play a critical role in regulating reperfusion following cerebrovascular obstruction; however, methods to evaluate their temporospatial remodeling remains under investigation. NEW METHOD: We combined arteriole-specific vessel painting with histological evaluation to assess the density and diameter of inter-collateral vessels between the middle cerebral artery and anterior cerebral artery (MCA-ACA) or posterior cerebral artery (MCA-PCA) in a murine model of permanent middle cerebral artery occlusion (pMCAO). RESULTS: While the overall density was not influenced by pMCAO, the size of MCA-ACA and MCA-PCA vessels had significantly increased 2days post-pMCAO and peaked by 4days compared to the un-injured hemisphere. Using a combination of vessel painting and immunofluorescence, we uniquely observed an induction of cellular division and a remodeling of the smooth muscle cells within the collateral niche following post-pMCAO on whole mount tissue sections. Vessel painting was also applied to pMCAO-injured Cx3cr1GFP mice, in order to identify the spatial relationship between Cx3cr1-positive peripheral-derived monocyte/macrophages and the vessel painted collaterals. Our histological findings were supplemented with analysis of cerebral blood flow using laser Doppler imaging and behavioral changes following pMCAO. COMPARISON WITH EXISTING METHODS: Compared to polyurethane and latex methods for collateral labeling, this new method provides detailed cell-type specific analysis within the collateral niche at the microscopic level, which has previously been unavailable. CONCLUSIONS: This simple and reproducible combination of techniques is the first to dissect the temporospatial remodeling of pial collateral arterioles. The method will advance investigations into the underlying mechanisms governing the intricate processes of arteriogenesis.

Effects of Dl-3-n-butylphthalide on Cerebral Ischemia Infarction in Rat Model by Mass Spectrometry Imaging.

Dl-3-n-butylphthalide (NBP) is a drug that is used in the treatment of ischaemic stroke. However, to the best of our knowledge, there are no systematic studies investigating the effects of dl-3-n-butylphtalide on the brain metabolism of small molecules. In this study, we first investigated the effects of dl-3-n-butylphthalide on the spatial distribution of small molecules in the brains of rats with permanent middle cerebral artery occlusion (pMCAO) using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) imaging. After pMCAO modelling or a sham operation, rats were given four mg/kg of dl-3-n-butylphthalide through the caudal vein or saline once a day for nine days. The degree of neurological deficit in rats was evaluated using the modified neurological severity score (mNSS). MALDI-TOF-MS imaging was used to observe the content and distribution of small molecules related to metabolism during focal cerebral ischaemia. Multiple reaction monitoring (MRM) mode with liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to verify the results obtained from MALDI-TOF-MS imaging. These small molecules were found to be involved in glucose metabolism, ATP metabolism, the glutamate-glutamine cycle, malate aspartate shuttle, oxidative stress, and inorganic ion homeostasis. Of the 13 metabolites identified by MALDI-TOF-MS imaging, seven compounds, ATP, ADP, AMP, GMP, N-acetylaspartic acid, ascorbic acid and glutathione, were further validated by LC-MS/MS. Taken together, these results indicate that dl-3-n-butylphthalide significantly improved ATP metabolism, level of antioxidants, and sodium-potassium ion balance in a rat model of pMCAO.

Spatio-temporal activation of caspase-8 in myeloid cells upon ischemic stroke.

Ischemic stroke (caused by thrombosis, embolism or vasoconstriction) lead to the recruitment and activation of immune cells including resident microglia and infiltrating peripheral macrophages, which contribute to an inflammatory response involved in regulation of the neuronal damage. We showed earlier that upon pro-inflammatory stimuli, the orderly activation of caspase-8 and caspase-3/7 regulates microglia activation through a protein kinase C-δ dependent pathway. Here, we present in vivo evidence for the activation of caspase-8 and caspase-3 in microglia/macrophages in post-mortem tissue from human ischemic stroke subjects. Indeed, CD68-positive microglia/macrophages in the ischemic peri-infarct area exhibited significant expression of the cleaved and active form of caspase-8 and caspase-3. The temporal and spatial activation of caspase-8 was further investigated in a permanent middle cerebral artery occlusion mouse model of ischemic stroke. Increasing levels of active caspase-8 was found in Iba1-positive cells over time in the peri-infarct area, at 6, 24 and 48 h after artery occlusion. Analysis of post-mortem brain tissue from human subject who suffered two stroke events, referred as recent and old stroke, revealed that expression of cleaved caspase-8 and -3 in CD68-positive cells could only be found in the recent stroke area. Analysis of cleaved caspase-8 and -3 expressions in a panel of human stroke cases arranged upon days-after stroke and age-matched controls suggested that the expression of these caspases correlated with the time of onset of stroke. Collectively, these data illustrate the temporal and spatial activation of caspase-8 and -3 in microglia/macrophages occurring upon ischemic stroke and suggest that the expression of these caspases could be used in neuropathological diagnostic work.

Neuroinflammatory response to experimental stroke is inhibited by eriodictyol.

BACKGROUND: Cerebral ischemia is a common disease and one of the most common causes of death and disability worldwide. The lack of glucose and oxygen in neuronal tissue leads to a series of inflammatory events, culminating in neuronal death. Eriodictyol is a flavonoid isolated from the Chinese herb Dracocephalum rupestre that has been proven to have anti-inflammatory properties. HYPOTHESIS/PURPOSE: Thus, the present study was designed to explore whether eriodictyol has neuroprotective effects against the neuronal damage, motor and memory deficits induced by permanent middle cerebral artery occlusion (pMCAO) in mice. STUDY DESIGN: Animals were orally treated with eriodictyol (1, 2 and 4mg/kg) or vehicle (saline) 30min before pMCAO, 2h after, and then once daily for the following five days. METHODS: The parameters studied were neuronal viability, brain infarcted area; sensorimotor deficits; exploratory activity; working and aversive memory; myeloperoxidase (MPO) activity; TNFα, iNOS and GFAP immunoreactivity. RESULTS: The treatment with eriodictyol prevented neuronal death, reduced infarct area and improved neurological and memory deficits induced by brain ischemia. The increase of MPO activity and TNF-α, iNOS and GFAP expression were also reduced by eriodictyol treatment. CONCLUSION: These findings demonstrate that eriodictyol exhibit promising neuroprotection effects against the permanent focal ischemia cerebral injury in the mice experimental model and the underlying mechanisms might be mediated through inhibition of neuroinflammation.