RESUMO
Ischemia and hypoxia cause functional damage to brain tissues during stroke， and when blood supply is restored to brain tissues after ischemia， a large number of free radicals and calcium overload cause cerebral ischemia-reperfusion injury， which further aggravates the condition. Autophagy is a self-protection mechanism that maintains the homeostasis of the intracellular environment， but excessive autophagy causes brain tissue damage. MiRNA is a small endogenous non-coding RNA molecule that regulate various physiological activities at the gene level by binding to complementary sequences in the 3 '- UTR of its target gene mRNA， leading to translation inhibition or mRNA degradation. MiRNA not only directly acts on autophagy related proteins， but also participates in autophagy regulation induced by ischemia/reperfusion through various signaling pathways. However， there is still a lack of systematic induction and analysis of miRNA regulation of autophagy signaling pathways induced by cerebral ischemia/reperfusion. This article reviews the regulation of cellular autophagy during cerebral ischemia/ reperfusion by miRNA-124， miRNA-298， miRNA-202-5p， miRNA-142， miRNA-26b and so on through different signaling pathways， providing a systematic and theoretical approach for the study of autophagy in stroke.
RESUMO
Cerebral ischemia/reperfusion injury （CIRI） is a complex cascade reaction process in which the blood flow and oxygen supply of brain tissue in the infarcted area recover after cerebral ischemia， resulting in secondary injury of ischemic brain tissue. At present， thrombolysis as soon as possible and restoration of cerebral blood supply are still the only strategies for the treatment of stroke， but a considerable number of patients' symptoms will be more serious after reperfusion， making patients face adverse outcomes such as neurological function injury and even death and seriously affecting the quality of life and safety of patients. Therefore， an in-depth exploration of the mechanism and treatment strategy of CIRI has important clinical significance. The phosphatidylinositol 3- kinase （PI3K）/protein kinase B （Akt） signaling pathway is one of the classic anti-apoptosis/reproductive-promoting signal transduction pathways， which is responsible for cell proliferation， growth， and differentiation. It is the key cascade signaling pathway of CIRI， located at the core site in many mechanisms such as mitochondrial disorder， apoptosis， autophagy， oxidative stress， and inflammation. It is closely related to the occurrence and development of CIRI. Traditional Chinese medicine has been used in the clinical treatment of stroke and its complications for thousands of years， and the clinical effect of traditional Chinese medicine in the prevention and treatment of CIRI has been affirmed by a large number of research results in recent years. It is further clarified that the monomers， active components， and their compound prescriptions of traditional Chinese medicine can directly or indirectly regulate the PI3K/Akt signaling pathway by virtue of the biological advantages of multi-targets， multi-components， and multi-pathways and play an overall protective role in CIRI. By analyzing the related research progress of traditional Chinese medicine in China and abroad in recent years， the authors summarized the role and mechanism of regulating the PI3K/Akt signaling pathway in the prevention and treatment of CIRI， so as to provide further theoretical basis for the study of the mechanism of clinical prevention and treatment of CIRI.
RESUMO
Objective To investigate the potential effect and mechanism of curcumin in inhibiting synaptic injury in the cortex of rats with cerebral ischemia-reperfusion. Methods Sprague-Dawley rats were divided into sham-operated group, model group, low-dose curcumin (50 mg/kg) group, and high-dose curcumin (100 mg/kg) group. A model of middle cerebral artery occlusion for 2 hours and reperfusion for 24 hours was constructed, and curcumin was administered. Based on the neurological function score, the effects of curcumin on cerebral infarct volume, synaptic ultrastructure changes, inflammatory cell infiltration, and the expression of NLRP3, Caspase-1, Synapsin1, and CAMKⅡ were observed after the end of the animal treatment. Results The neurological function scores were 0, 3.25±0.43, 2.50±0.50, and 1.50±0.50 for the sham-operated group, model group, low-dose curcumin group, and high-dose curcumin group, respectively. The percentage of cerebral infarct volume was 0, (38.89±2.21)%, (33.48±1.77)%, and (23.69±2.19)%, respectively. Compared with the sham operation group, the model group had severe synaptic ultrastructure damage, extensive inflammatory cell infiltration, significantly increased expression of Caspase-1 and NLRP3 (P < 0.5), and significantly decreased expression of Synapsin1 and CAMKⅡ (P < 0.5). Curcumin treatment significantly inhibited synaptic damage, reduced inflammatory cell infiltration, decreased the expression of Caspase-1 and NLRP3 (P < 0.5), and increased the expression of Synapsin1 and CAMKII (P < 0.5), when compared with the model group. Conclusion Ischemia-reperfusion-mediated synaptic injury in rat brain triggers an inflammatory response in cortical nerve cells, and curcumin alleviates synaptic damage and reduces brain injury by inhibiting inflammatory factor levels.
RESUMO
AIM: To investigate the effect of gastrodin on the expression of brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) in the striatum of cerebral ischemia rats, and to explore the potential mechanism of gastrodin in treating cerebral ischemia. METHODS: The rats were randomly divided into four groups: normal, sham, model, and gastrodin groups, each consisting of 10 rats. After successful modeling using middle cerebral artery occlusion (MCAO), the gastrodin group received intraperitoneal injection of gastrodin injection at a dose of 10 mg/kg once a day for 14 consecutive days. Pathological changes in striatal neurons were observed using Nissl staining. Immunohistochemistry was utilized to detect positive expression of BDNF and IL-6 proteins in the striatum. Additionally, immunoblot analysis was performed to determine the expression levels of BDNF and IL-6 proteins in the striatum. RESULTS: Nissl staining revealed clear and intact structures of striatal neurons in the normal and sham groups, with tightly arranged cells. In the model group, the number of cells was significantly reduced compared to the sham group (P0.05). Compared to the sham group, the model group showed a decrease in the protein expression level of BDNF in the striatum on the ischemic side (P<0.01) and an increase in the protein expression level of IL-6 (P<0.05, P<0.01). In contrast, the gastrodin group showed an increase in the protein expression level of BDNF in the striatum on the ischemic side (P<0.05, P<0.01) and a decrease in the protein expression level of IL-6 (P< 0.05, P<0.01) compared to the model group. CONCLUSION: Gastrodin has a significant protective effect on striatal injury caused by cerebral ischemia, and its mechanism may be related to the up-regulation of the anti-inflammatory factor BDNF and the down-regulation of the pro-inflammatory factor IL-6.
RESUMO
Aim To investigate the regulatory effect of geraniol on Nrf2/HO-1 signaling pathway after cerebral ischemia-reperfusion(I/R)in rats. Methods In this experiment,all the male SD rats were randomly divided into nine groups receiving the following treatments:sham operation(sham); sham operation+200 mg·kg-1 geraniol; I/R; I/R+50 mg·kg-1 geraniol; I/R+100 mg/kg geraniol; I/R+200 mg·kg-1 geraniol; edaravone; I/R+ brusatol(Nrf2 inhibitor); I/R+200mg·kg-1 geraniol+brusatol. All rats received intraperitoneal injection of geraniol for five consecutive days before MCAO and again after MCAO. During the construction of cerebral I/R injury models,the blood vessels were isolated without any suture in the sham operation and the sham operation +200 mg·kg-1 geraniol groups while the blood vessels with suture in other groups. The damage of neurological function was evaluated by the modified rating scale for neurological function. The TTC,HE and Tunel staining methods were used to determine the cerebral infarction volume,the damage of the ischemic cortex and the apoptosis of cortical cells,respectively. The oxidative stress-related parameters then were measured. The protein expressions of Nrf2 and HO-1 were detected by immunohistochemical staining and the target protein expressions of the injured cortex were detected by Western blot. Results Compared with the model group,it was found that the geraniol treatment significantly repaired neural injury,reduced cerebral infarction volume,cerebral cortex damage and cell apoptosis. Meanwhile,geraniol intervention could significantly increase the expression of Nrf2/HO-1 protein in the right-sided cortex and reduce oxidative stress level. Conclusion Geraniol can attenuate cerebral injury induced by ischemia-reperfusion in rats via activating Nrf2/HO-1 signaling pathway.
RESUMO
Aim To investigate the dynamic time-course changes in neuronal cytoskeleton after acute ischemia and reperfusion in rats. Methods Reperfusion was performedin rats by blocking the middle cerebralarteryfor 90 min, then therats wereobserved and collected at different time points. The brain damage wasobserved by Nissl staining,and neurobehavioural function was evaluated with neurological deficit score and forelimb placement test. The cellular changes in the alternations of cytoskeletal elements including microtubule associated protein 2 (MAP2) and neurofilament heavy chain (NF-H) were observed by immunohistochemistry staining and Western blot. Impaired axons, dendrites and cytoskeletal alternations were detected by electron microscope. Results Brain damage and neurobehavioural function were gradually aggravated with the prolongation of reperfusion. Brain damage appeared earlier and more severe in striatum than in cortex. Moreover, decreased MAP2-related and increased NF-H-related immunoreactive intensities were found in the ischemic areas. Impaired cytoskeletal arrangement and reduced dense were indicated. Damaged cytoskeletal components such as microtubules and neurofilament arrangement, decreased axonal filament density, and swelled dendrites were observed after cerebral ischemia reperfusion by ultrastructural observations. Conclusions Different brain regions have diverse tolerance to ischemia-reperfusion injury. Major elements of neuronal cytoskeleton show dynamic responses to ischemia and reperfusion, which may further contribute to brain damage and neurological impairment following MCAO and reperfusion.
RESUMO
Aim To investigate whether alisol A (AA) could improve the blood brain barrier (BBB) mediated cortex cerebral ischemia-repeifusion injury (CIRI) by inhibiting matrix metalloproteinase 9 (MMP-9). Methods The global cerebral ischemia- reperfusion (GCI/R) model in mice was established, and the AA was intragastric injected subsequently for seven days. The modified neurological severity scores (mNSS), open field test and Y-maze test were applied to detect neurological function. Magnetic resonance spectroscopy (MRS) was used to detect relevant neu- rosubstance metabolism in cortex of mice. Transmission electron microscope (TEM) was employed to observe the ultrastructure of BBB in cortex. Western blot and immunohistochemistry were used to detect the MMP-9 level in cortex. The binding possibility of A A and MMP-9 was determined by molecular docking. Results Compared with Sham group, mice in GCI/R group have an increased mNSS score but decreased at total distance and center distance to total distance ratio in open field test as well as alternation rate in Y-maze test (P<0.01). While mice in GCI/R + AA group have a decreased mNSS score but increased at total distance and center distance to total distance ratio in open field test as well as alternation rate in Y-maze test (P<0.01) compared with GCI/R group. MRS results found that in cortex of GCI/R group mice, the level of GABA and NAA significantly decreased while the Cho, mI and Tau level increased (P<0.01). Whereas in GCI/R + AA group mice, the GABA and NAA level increased and the Cho, ml and Tau decreased significantly (P<0.01). By TEM we observed that the basilemma of cerebral microvessels collapsed, the lumen narrowed, the endothelial cells were active and plasma membranes ruffled, gaps between cells were enlarged and tight junctions were damaged and the end feet of astrocytes were swollen in GCI/R group mice. While in GCI/R + AA group mice, the lumen was filled, plasma membranes of endothelial cells were smooth, tight junctions were complete and end feet of astrocytes were in normal condition. Western blot and immunohistochemistry both found that the MMP-9 level increased in GCI/R group mice (P < 0.01) and decreased in GCI/R + AA group mice (P < 0.05). Molecular docking proved the binding between aliso A and MMP9 through TYR-50 and ARG-106, and the binding energy was calculated as -6.24 kcal · mol
RESUMO
OBJECTIVE To explore the protective effect and mechanism of Longshengzhi capsules on cerebral ischemia- reperfusion injury in rats. METHODS The model of middle cerebral artery occlusion （MCAO） was established by using the improved thread occlusion method. The experiment was divided into six groups： sham surgery group （only separating blood vessels without inserting thread plugs， given the same volume of normal saline）， model group （modeling， given the same volume of normal saline）， nimodipine group （positive control， modeling， dose of 20 mg/kg）， and low-dose， medium-dose， and high-dose groups of Longshengzhi capsules （modeling， doses of 0.72， 1.44 and 2.88 g/kg， respectively）， with 10 mice in each group. Each group was given corresponding medication solution/normal saline by gavage， once a day， for 7 consecutive days. One hour after the last administration， the Zea Longa scoring method was used to score the neurological deficits in each group of rats， and the ABC enzyme-linked immunosorbent assay was used to detect the serum levels of tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in rats； TTC staining was used to observe the volume of cerebral infarction in rats and calculate the cerebral infarction volume ratio. Hematoxylin eosin staining was used to observe the pathological changes in the brain tissue of rats. Immunohistochemical staining was used to detect the positive expression of NLRP3 protein in the brain tissue of rats. Real-time fluorescence quantitative PCR was used to detect mRNA relative expressions of Toll-like receptor 4 （TLR4） and nuclear factor-κB （NF-κB） in the brain tissue of rats. Western blot assay was adopted to detect the relative expressions of TLR4， NLRP3 and phosphorylated NF-κB （p-NF-κB） protein in the brain tissue of rats and its intracellular NF-κB protein. RESULTS Compared with the sham surgery group， the neural dysfunction score， serum levels of TNF-α and IL-6， cerebral infarction volume ratio， relative expression levels of NF-κB and TLR4 mRNA， as well as protein relative expressions of TLR4， NLRP3 and p-NF-κB in the brain tissue， and relative protein expression of intracellular NF-κB were increased significantly in the model group （P＜0.01）； the enlarged gap and significant edema were observed in cortical nerve cells of brain tissue in rats， with a large amount of inflammatory cell infiltration； the positive expression of NLRP3 protein in brain tissue of rats obviously increased. Compared with the model group， the levels of the above indicators in the medium-dose and high-dose groups of Longshengzhi capsules， as well as the Nimodipine group， were reversed to varying degrees， and most differences were statistically significant （P＜0.05 or P＜0.01）； the pathological morphology observation showed a significant improvement， and the positive expression of NLRP3 protein in the brain tissue of rats was obviously reduced. CONCLUSIONS Longshengzhi capsules may inhibit TLR4/NF-κB/NLRP3 signaling pathway and neuroinflammatory response， thereby achieving a protective effect against cerebral ischemia-reperfusion injury in rats.
RESUMO
Abstract Background The precise underlying mechanism of antioxidant effects of dexmedetomidine-induced neuroprotection against cerebral ischemia has not yet been fully elucidated. Activation of Nuclear factor erythroid 2-related factor (Nrf2) and Heme Oxygenase-1 (HO-1) represents a major antioxidant-defense mechanism. Therefore, we determined whether dexmedetomidine increases Nrf2/HO-1 expression after global transient cerebral ischemia and assessed the involvement of Protein Kinase C (PKC) in the dexmedetomidine-related antioxidant mechanism. Methods Thirty-eight rats were randomly assigned to five groups: sham (n = 6), ischemic (n = 8), chelerythrine (a PKC inhibitor; 5 mg.kg-1 IV administered 30 min before cerebral ischemia) (n = 8), dexmedetomidine (100 µg.kg-1 IP administered 30 min before cerebral ischemia (n = 8), and dexmedetomidine + chelerythrine (n = 8). Global transient cerebral ischemia (10 min) was applied in all groups, except the sham group; histopathologic changes and levels of nuclear Nrf2 and cytoplasmic HO-1 were examined 24 hours after ischemia insult. Results We found fewer necrotic and apoptotic cells in the dexmedetomidine group relative to the ischemic group (p< 0.01) and significantly higher Nrf2 and HO-1 levels in the dexmedetomidine group than in the ischemic group (p< 0.01). Additionally, chelerythrine co-administration with dexmedetomidine attenuated the dexmedetomidine-induced increases in Nrf2 and HO-1 levels (p< 0.05 and p< 0.01, respectively) and diminished its beneficial neuroprotective effects. Conclusion Preischemic dexmedetomidine administration elicited neuroprotection against global transient cerebral ischemia in rats by increasing Nrf2/HO-1 expression partly via PKC signaling, suggesting that this is the antioxidant mechanism underlying dexmedetomidine-mediated neuroprotection.
Assuntos
Animais , Ratos , Traumatismo por Reperfusão/prevenção & controle , Isquemia Encefálica , Proteína Quinase C/metabolismo , Proteína Quinase C/farmacologia , Ataque Isquêmico Transitório , Estresse Oxidativo , Fármacos Neuroprotetores/farmacologia , Dexmedetomidina/farmacologia , Heme Oxigenase-1/metabolismo , Heme Oxigenase-1/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/farmacologia , Heme Oxigenase (Desciclizante)/farmacologia , Antioxidantes/metabolismo , Antioxidantes/farmacologiaRESUMO
OBJECTIVE To investigate the role of PDE4 inhibition in astrocyte swelling caused by cerebral ischemic/reperfusion(I/R)injury and the molecular mech-anisms.METHODS SD rats were subjected to 2 h of focal cerebral ischemia induced by middle cerebral artery occlusion/reperfusion(MCAO/R).Roflumilast(Roflu)was intraperitoneally injected 2 h after MCAO.At 24 h after reperfusion,a high-resolution MRI was performed and using the wet-dry weighting method to measure the water content.The oxygen-glucose deprivation/reoxygenation(OGD/R)model was established in primary astrocytes for 2 h.After 24 h of reoxygenation,CellMask? plasma membrane stain was used to label the plasma membrane to calculate cell volume.The protein expressions insides astrocytes and penumbra were detected by Western blot-ting.To investigate the role of Akt/FoxO3a in mediating the effect of Roflu on the expression of AQP4.The astro-cytes were treated with an Akt inhibitor MK2206 before treatment with Roflu and the activation of Akt,the expres-sion of AQP4 and cell volume were determined as described above.In addition,an IL-1β-stimulated cell model was established in astrocytes,the expression of AQP4 and the activation of Akt/FoxO3a were detected by Western blotting.The change of AQP4 expression inside astrocytes and penumbra were visualized by immunofluo-rescence staining.RESULTS Roflu reduced MCAO/R-induced water contents,the expression of AQP4 and the phsophorylation of Akt and FoxO3a in the brains of MCAO/R rats.Inhibition of PDE4 decreased the cell volume and the expression of AQP4 in primary astro-cytes subjected to OGD/R.PDE4 inhibition activated Akt/FoxO3a,and inhibition of Akt by MK2206 blocked the protective effect of Roflu against OGD/R induced astro-cyte swelling.PDE4B knocking down reduced the expres-sion of AQP4,while PDE4B overexpression reversed the effect of PDE4B siRNA in astrocytes.Roflu exert-ed similar protective effect in IL-1β-cultured astrocytes,and importantly overexpression of FoxO3a remarkably increased the expression of AQP4 in IL-1β-stimulated astrocytes.CONCLUSION Our findings indicate that PDE4 inhibition limits I/R-induced brain edema and astro-cyte swelling via the Akt/FoxO3a/AQP4 pathway.PDE4 inhibition is a promising strategy for the treatment of brain edema after I/R injury.
RESUMO
Ischemic stroke is an acute and serious cerebrovascular accident.Neurodegenerative disorders are characterized by progressive degeneration of neu-rons in the central nervous system(CNS),resulting in severe disability and death.Myelin is essential for the health and function of neuronal axons.Oligodendrocytes,the myelinating cells of CNS,are vulnerable to ischemia and neurodegenerative disorders.G protein-coupled receptor 17(GPR17)is a dual receptor activated by uracil nucleotides/cysteinyl leukotrienes(CysLTs).Abnormal GPR17 activation contributes to oligodendrocyte dysfunc-tion and axonal damage.Gelosa et al.reported that CysLT1 receptor antagonist montelukast increased the recruitment and proliferation of oligodendrocyte precursor cells(OPCs)at the acute phase after ischemic stroke.Similarly,a study showed that montelukast stimulated neural progenitor proliferation and hippocampal neuro-genesis of aged rats through inhibition of GPR17.These results were supported by several studies on neurode-generative diseases.The authors showed that pharmaco-logical blockade of GPR17 with CysLT1 or CysLT2 recep-tor antagonists(montelukast or HAMI3379)improved oli-godendrocyte function and fiber connectivity,highlighting GPR17 as a potential therapeutic target in oligodendro-cyte protection and remyelination.Recently,growing evi-dence has revealed a significant interaction between mi-croglia and oligodendrocytes in CNS injury and disease.It was reported that M2 microglia promoted,while M1 microglia inhibited oligodendrogenesis,OPCs maturation and remyelination.Microglia-mediated neuroinflamma-tion,considered as an important pathological event,neg-atively affected OPCs fate and function in experimental neurological disorders.This was further corroborated by later studies.It was recently reported that montelukast enhanced OPCs differentiation and maturation by upreg-ulating the number of M2 microglia at chronic phase of brain ischemia.In line with the above results,inhibition of microglial inflammation by montelukast was shown to be responsible for neurite outgrowth.Although the exact mechanisms were not fully clarified,these results indi-cate that montelukast may indirectly promote OPCs dif-ferentiation and remyelination by a microglia-dependent manner.It has been widely accepted that CysLT1,CysLT2 and GPR17 receptors are localized in various cell types and their expression are upregulated after brain damage.Therefore,it is likely that CysLT receptor antagonists confer neuroprotection by targeting different receptors and multiple cell functions.Many studies have reported that CysLT receptor antagonists promote protec-tion of oligodendrocytes by inhibiting GPR17.Moreover,they may improve OPCs differentiation and neuronal sur-vival by regulating CysLTs-mediated microglial activation.Altogether,these data open novel perspectives in the treatment of cerebral ischemia and neurodegenerative diseases.
RESUMO
Objective:To explore the mechanism of gypenoside ⅩⅦ against cerebral ischemia/reperfusion (I/R) through nuclear factor erythroid 2-related factor 2/antioxidant responsive element (Nrf2/ARE) signaling pathway.Methods:Forty SPF Sprague Dawley (SD) rats were randomly divided into sham operated group, I/R model group, 25, 50 and 100 mg/kg gypenoside ⅩⅦ groups ( n = 8). Gypenoside ⅩⅦ groups were administered 25, 50 or 100 mg/kg (0.01 mL/g) gypenoside ⅩⅦ by intragastric administration for 14 days; the other two groups received the same dose of saline. Rat cerebral I/R model was established by modified line bolt method; rats in the sham operated group underwent the same procedure without producing substantial embolization. After 24 hours of reperfusion, the neurological deficit scores of the rats in each group were assessed. Rat abdominal aortic whole blood was collected and the serum reactive oxygen species (ROS), heme oxygenase-1 (HO-1), γ-glutamylcysteine synthase (γ-GCS), superoxide dismutase (SOD), quinone NADH oxidoreductase 1 (NQO1), and malondialdehyde (MDA) were detected. Then whole brain tissue was harvested and penumbra tissue was isolated from cerebral cortex, the general condition of rat brain tissue and the volume of cerebral infarction were evaluated, the histopathological changes in the brain were observed under light microscopy, the mRNA expressions of Nrf2 and Keap1 were measured by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR), the protein expressions of Nrf2 and Keap1 were determined by Western blotting. Results:After 24 hours of reperfusion, compared with the sham operated group, the score of neurological deficit and infarct volume were significantly increased, the NQO1, SOD and γ-GCS levels in serum were significantly decreased, MDA, HO-1 and ROS levels in serum were significantly increased, the Nrf2 and Keap1 mRNA and protein expressions in the ischemic penumbra were significantly increased in rats from I/R model group. Compared with the I/R model group, the neurological deficit scores (1.50±0.53, 1.37±0.52 vs. 2.75±0.46) and brain infarct volume [(19.8±5.1)%, (21.4±6.4)% vs. (42.3±5.8)%] were significantly reduced, serum NQO1, SOD, HO-1 and γ-GCS were significantly increased [NQO1 (ng/L): 186.05±10.38, 220.75±16.22 vs. 131.36±5.95, SOD (kU/L): 63.23±5.30, 72.70±8.62 vs. 36.75±6.55, HO-1 (ng/L): 60.57±7.93, 60.35±4.72 vs. 42.72±4.95, γ-GCS (kU/L): 8.81±0.53, 8.72±0.69 vs. 6.80±0.56], serum MDA and ROS levels were significantly reduced [MDA (μmol/L): 5.94±0.66, 5.61±0.53 vs. 10.88±1.34, ROS (kU/L): 69.11±4.23, 67.12±4.52 vs. 104.43±7.54], the mRNA and protein expressions of Nrf2 and Keap1 in the ischemic penumbra were significantly increased in rats from 50 mg/kg and 100 mg/kg gypenoside ⅩⅦ groups [Nrf2 mRNA (2 -△△Ct): 1.90±0.13, 2.13±0.18 vs. 1.48±0.11, Keap1 mRNA (2 -△△Ct): 1.78±0.11, 1.85±0.10 vs. 1.43±0.10, Nrf2/β-actin: 0.73±0.04, 0.79±0.03 vs. 0.60±0.03, Keap1/β-actin: 0.71±0.01, 0.76±0.03 vs. 0.61±0.01], all the comparative differences were statistically significant (all P < 0.01); 25 mg/kg gypenoside ⅩⅦ had no significant effect. Conclusion:Gypenoside ⅩⅦ (50 mg/kg and 100 mg/kg) may play a role in anti-cerebral I/R injury by regulating NQO1, SOD, HO-1, γ-GCS, ROS and MDA through Nrf2/ARE signaling pathway.
RESUMO
Stroke is the second leading cause of death worldwide,and oxidative stress plays a crucial role.Celastrol exhibits strong antioxidant properties in several diseases;however,whether it can affect oxidation in cerebral ischemic-reperfusion injury(CIRI)remains unclear.This study aimed to determine whether celastrol could reduce oxidative damage during CIRI and to elucidate the underlying mechanisms.Here,we found that celastrol attenuated oxidative injury in CIRI by upregulating nuclear factor E2-related factor 2(Nrf2).Using alkynyl-tagged celastrol and liquid chromatography-tandem mass spectrometry,we showed that celastrol directly bound to neuronally expressed developmentally downregulated 4(Nedd4)and then released Nrf2 from Nedd4 in astrocytes.Nedd4 promoted the degradation of Nrf2 through K48-linked ubiquitination and thus contributed to astrocytic reactive oxygen species production in CIRI,which was significantly blocked by celastrol.Furthermore,by inhibiting oxidative stress and astrocyte activation,celastrol effectively rescued neurons from axon damage and apoptosis.Our study uncovered Nedd4 as a direct target of celastrol,and that celastrol exerts an antioxidative effect on as-trocytes by inhibiting the interaction between Nedd4 and Nrf2 and reducing Nrf2 degradation in CIRI.
RESUMO
OBJECTIVE@#To improve the classical 4-vessel occlusion (4VO) model established by Pulsinelli and Brierley.@*METHODS@#Thirty-two male SD rats were randomized into sham operation group, I4VO-Con10 group, I4VO-Int10 group and I4VO-Int15 group. The sham surgery group underwent exposure of the bilateral vertebral arteries and carotid arteries without occlusion to block blood flow. The I4VO-Con10 group experienced continuous ischemia by occluding the bilateral vertebral arteries and carotid arteries for 10 minutes followed by reperfusion for 24 hours. The I4VO-Int10 and I4VO-Int15 groups were subjected to intermittent ischemia. The I4VO- Int10 group underwent 5 minutes of ischemia, followed by 5 minutes of reperfusion and another 5 minutes of ischemia, and then reperfusion for 24 hours. The I4VO-Int15 group experienced 5 minutes of ischemia followed by two cycles of 5 minutes of reperfusion and 5 minutes of ischemia, and then reperfusion for 24 hours. The regional cerebral blood flow (rCBF) was monitored with laser Doppler scanning, and survival of the rats was observed. HE staining was used to observe hippocampal pathologies to determine the optimal method for modeling. Another 48 rats were randomized into 6 groups, including a sham operation group and 5 model groups established using the optimal method. The 5 I4VO model groups were further divided based on the reperfusion time points (1, 3, 7, 14, and 28 days) into I4VO-D1, I4VO-D3, I4VO-D7, I4VO- D14, and I4VO- D28 groups. Body weight changes and survival of the rats were recorded. HE staining was used to observe morphological changes in the hippocampal, retinal and optic tract tissues. The Y-maze test and light/dark box test were used to evaluate cognitive and visual functions of the rats in I4VO-D28 group.@*RESULTS@#Occlusion for 5 min for 3 times at the interval of 5 min was the optimal method for 4VO modeling. In the latter 48 rats, the body weight was significantly lower than that of the sham-operated rats at 1, 3, 7, 14 and 28 days after modeling without significant difference in survival rate among the groups. The rats with intermittent vessel occlusion exhibited progressive deterioration of hippocampal neuronal injury and neuronal loss. Cognitive impairment was observed in the rats in I4VO-D28 group, but no obvious ischemic injury of the retina or the optic tract was detected.@*CONCLUSION@#The improved 4VO model can successfully mimic the main pathological processes of global cerebral ischemia-reperfusion injury without causing visual impairment in rats.
Assuntos
Ratos , Masculino , Animais , Ratos Sprague-Dawley , Isquemia Encefálica , Infarto Cerebral , Traumatismo por Reperfusão , Peso CorporalRESUMO
OBJECTIVE@#To observe the effects of Xingnao Kaiqiao (regaining consciousness and opening orifices) acupuncture therapy on the expression of hypoxia-inducible factor 1α (HIF-1α) and Nod-like receptor protein 3 (NLRP3) in cerebral ischemia-reperfusion rats, and to explore the mechanism of acupuncture against cerebral ischemia-reperfusion injury.@*METHODS@#Seventy-two male SD rats were randomly divided into a sham-operation group, a model group, an acupuncture group and a non-point acupuncture group, with 18 rats in each one. Using modified Longa thread embolization method, the rat model of acute focal cerebral ischemia was prepared; and after 2 h ischemia, the reperfusion was performed to prepared the model of cerebral ischemia-reperfusion. Immediately after reperfusion, Xingnao Kaiqiao acupuncture method was applied to bilateral "Neiguan" (PC 6) and "Shuigou" (GV 26) in the acupuncture group, while in the non-point acupuncture group, acupuncture was delivered at non-points and all of the needles were retained for 30 min in these two groups. The samples were collected 24 h after reperfusion in the rats of each group. Zea-Longa neurological deficit score was used to evaluate the degree of cerebral neurological impairment, TTC staining was adopted to observe the volume percentage of cerebral infarction, HE staining was provided to observe the morphological changes of brain, and Western blot was applied for detecting the expression of HIF-1α and NLRP3 proteins in the cerebral cortex on the right side.@*RESULTS@#Compared with the sham-operation group, neurological deficit score and volume percentage of cerebral infarction were increased in the model group (P<0.01), and HIF-1α and NLRP3 protein expression was elevated (P<0.01). Compared with the model group, neurological deficit score and volume percentage of cerebral infarction were decreased (P<0.01), and HIF-1α and NLRP3 protein expression was lower (P<0.01) in the acupuncture group. There was no significant difference in above indexes in the non-point acupuncture group compared with the model group (P>0.05). Compared with the sham-operation group, the brain tissue of the rats in the model group and the non-point acupuncture group was loose and edema, and the nuclei were shriveled. The brain tissue morphology in the acupuncture group was similar to that of the sham-operation group.@*CONCLUSION@#Acupuncture can alleviate cerebral ischemia-reperfusion injury, and its mechanism may be related to the regulation of HIF-1α/NLRP3 signaling pathway to attenuate inflammatory response.
Assuntos
Masculino , Animais , Ratos , Ratos Sprague-Dawley , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Terapia por Acupuntura , Traumatismo por Reperfusão/terapia , Isquemia Encefálica/terapia , Infarto Cerebral/terapia , Proteínas NLRRESUMO
@#The aim of the present study was to investigate the effects of exosomes derived from bone marrow mesenchymal stem cells (BMSCs) on the polarization of M1/M2 microglia/macrophages in rats with acute cerebral ischemia.Ultrahigh-speed centrifugation was employed to isolate and identify exosomes; a middle cerebral artery occlusion (MCAO) model was prepared in rats using the intraluminal filament technique; Longa scoring and corner tests were used to evaluate the neurological function of rats; 2, 3, 5-triphenyltetrazole chloride (TTC) staining was used to assess the infarct volume in rat brains; immunofluorescence double-labeling of CD16/32/Iba1 and CD206/Iba1 was performed to detect M1/M2 phenotypes of microglia/macrophages; RT-qPCR was employed to measure the mRNA expression of CD86, inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNF-α), arginase-1 (Arg-1), interleukin-10 (IL-10), and transforming growth factor beta (TGF-β) in the ischemic penumbra of rat brains.The experimental results showed that BMSC-Exos reduced the number of CD16/32+/Iba1+ positive cells in the ischemic penumbra (P < 0.01) while increasing the number of CD206+/Iba1+positive cells (P < 0.01), and decreased the mRNA expression of iNOS, CD86, and TNF-α, while increasing the mRNA expression of Arg-1, TGF-β, and IL-10 (P < 0.05 or P < 0.01).This research suggests that BMSC-Exos can regulate M1/M2 polarization of microglia/macrophages in rats with acute cerebral ischemia, alleviate neuroinflammation, and improve ischemic brain injury.
RESUMO
Objective To detecte the expressions of phosphorylated p38 MAPK (p-p38 MAPK), Bax and Bcl-2 in the cerebral cortex of hyperlipidemia rats after cerebral ischemia-reperfusion (I/R) injury and the effect of SB203580 on the expressions of p-p38 MAPK, Bax and Bcl-2, to explore the effect of p38 MAPK activation on the expressions of Bax and Bcl-2 in hyperlipidemia cerebral I/R injury. Methods After the hyperlipidemia model was established, the rats were randomly divided into 3 groups: sham operation group, operation group (I/R) and SB203580 treatment group (SB+I/R), with 10 rats in each group. The focal cerebral I/R model in hyperlipemia rats was established with thread embolism of the left middle cerebral artery. The neurobehavioral score was used to observe the symptoms of neurobehavioral injury. The 2, 3, 5-triphenyltetrazolium chloride (TTC) staining was used to detect the volume of cerebral infarction, and the TUNEL staining was used to observe apoptotic cells. The relative expression levels of p-p38 MAPK, Bax and Bcl-2 were analyzed by immunohistochemistry. Results Compared with the sham group, the infarct volume, apoptosis index and neurobehavioral score of rats in the I/R group increased significantly, and the expressions of p-p38 MAPK and Bax increased significantly, and the expression of Bcl-2 decreased significantly (P<0. 05). Compared with the I/R group, rats in the SB+I/R group had less brain damage, the infarct volume and the apoptosis index were significantly reduced, the expressions of p-p38 MAPK reduced significantly, Bax expression decreased while Bcl-2 expression increased. The differences were statistically significant (P<0. 05). Neurobehavioral scores were lower in SB+I/R group than in I/R group, but the difference was not statistically significant. Conclusion In the process of cerebral I/R injury in hyperlipidemiarats, activation of p38 MAPK can regulate the expression of Bax and Bcl-2.
RESUMO
Objective To observe the effect of polyinosinic-polycytidylic acid ( Poly-IC ) treatment on the expressions of Bcl-2 and Bax after cerebral ischemia-reperfusion ( I / R ) injury in fryperlipidemia rats, and to detect the cerebral infarction, blood-brain barrier permeability and behavioral injury symptoms, to explore the neuroprotective effect of Poly-IC treatment on cerebral I /R injury in fryperlipidemia rats. Methods Hyperlipidemia rats were randomly divided into cerebral I /R group, Poly-IC pretreatment group, Poly-IC post-treatment group and sham operation group, 20 rats in each group. Neurobehavioral performance of rats in each group was recorded according to neurobehavioral score of 0-4 points. Blood-brain barrier permeability of rats in each group was detected by Evans blue staining. TTC staining was used to observe the cerebral infarction in each group. Apoptotic cells in the cerebral cortex of rats in each group was observed by TUNEL staining. The relative expression levels of Bcl-2 and Bax were determined by Western blotting. Results Compared with the sham group, the symptoms of neurobehavioral damage in the I/R group were serious and the score increased significantly (P<0. 05). The scores of Poly-IC pretreatment and post-treatment groups were significantly lower than that of I/R group (P<0. 05). Evans blue staining result showed that the blood-brain barrier permeability of the I/R group was significantly higher than that of the sham group (P<0. 05) , and Poly-IC pretreatment or post-treatment could significantly reduce the blood-brain barrier permeability ( P < 0. 05 ) . No infarct was observed in the sham group with uniform red staining, while white infarct was observed in the brain tissue of the I/R group. Compared with the I/R group, the volume of infarct in both Poly-IC pretreatment and post-treatment groups reduced significantly (P<0. 05). The apoptosis index in cerebral cortex of rats in I/R group was significantly higher than that in sham group ( P < 0 .05 ) , while the apoptosis index in Poly-IC pretreatment or post-treatment group was significantly lower than that in I/R group(P<0. 05 ) . The result of Western blotting showed that, compared with the sham group, the expression of Bax in the I/R group was significantly increased(P<0. 05) , the expression of Bcl-2 was significantly decreased(P<0. 05). Compared with the I/R group, the expression of Bax in the Poly-IC pretreatment or post-treatment group reduced significantly ( P < 0. 05 ) , the expression of Bcl-2 increased significantly(P<0. 05). Conclusion Poly-IC pretreatment or post-treatment can improve the symptoms of neurobehavioral injury, reduce the damage of blood-brain barrier, reduce the volume of cerebral infarction, decrease the apoptosis index of nerve cells, play a neuroprotective effect on cerebral ischemia reperfusion injury in rats with hyperlipidemia, and this protective effect may be related to the change of Bcl-2 and Bax expression levels.
RESUMO
Dihydromyricetin is a dihydroflavone compound which widely exists in ampelopsis of grapevine family. It has many pharmacological effects, such as anti-inflammatory, antibacterial, anti-tumor, antioxidant, regulating blood glucose, reducing blood lipid, liver protection and so on. In recent years, it has been found that dihydromyricetin has a good neuroprotective effect and can play a certain pharmacological role in a variety of neurological diseases, including Alzheimer' s disease, depression, Parkinson's disease and stroke. The purpose of this paper is to review the research on the neuroprotective effect of dihydromyricetin in the past decade.
RESUMO
Aim To observe cellular damage and astrocyte activation at different time points of cerebral ischemia and reperfusion. Methods The middle cerebral artery of male SpragueDawley rats was occluded for 90 min followed by different time points of reperfusion. Eighty-five SPF male SD rats were randomly divided into control group (Sham), IR3, 6, 12, 24 and IR48h (MCAO followed by 48 h of reperfusion) group. Cerebral ischemia and reperfusion injury was observed by HE staining, and the structure of astrocytes was estimated with transmission electron microscopy (TEM). GFAP expression was detected by immunofluorescence staining and Western blot. Results Cerebral ischemia following by different time points of reperfusion led to different degrees of cellular damage, which was the most serious at 24 h of reperfusion. TEM showed destruction of astrocytes structure, swollen organelles and broken mitochondrial ridge. After cerebral ischemia-reperfusion, the expression levels of GFAP were significant up-regulated in the ischemic penumbra cortex and the highest was at 48 h of reperfusion, indicating astrocytes were activated. In addition, the results showed the gradual decrease in GFAP expression in the infarct core. Conclusions After cerebral ischemia-reperfusion, cellular damage is aggravated, and astrocytes are gradually activated in the ischemic penumbra. With the extension of reperfusion time, the boundaries of infarct area and ischemic area are gradually clear, and scarring may occur.