Δ9-Tetrahydrocannabinol (THC) Impairs CD8+ T Cell-Mediated Activation of Astrocytes

CD8⁺ T cells can contribute to neuroinflammation by secretion of inflammatory cytokines like interferon γ (IFNγ) and tumor necrosis factor α (TNFα). Astrocytes, a glial cell in the brain, can be stimulated by IFNγ and TNFα to secrete the inflammatory cytokines, monocyte chemotactic protein 1 (MCP-1), interleukin 6 (IL-6), and interferon-γ inducible protein 10 (IP-10). Δ⁹-Tetrahydrocannabinol (THC), the primary psychoactive cannabinoid in Cannabis sativa, possesses potent anti-inflammatory activity. The objective of this investigation was to assess the effects of THC treatment on CD8⁺ T cell-mediated activation of astrocytes. CD3/CD28/IFNα- stimulated CD8⁺ T cells were treated with vehicle (0.03% EtOH) or THC and cocultured with U251 astrocytes. IP-10⁺, MCP-1⁺, and IL-6⁺ astrocytes were quantified by flow cytometry. LegendPlex™ was used to measure cytokine secretion by CD8⁺ T cells and flow cytometry was employed to quantify IFNγ, TNFα, and lysosomal-associated membrane protein 1 (LAMP-1) expression. Recombinant TNFα and IFNγ were used to stimulate MCP-1, IP-10, IL-6 responses in U251 astrocytes, which were measured by flow cytometry. Treatment with THC reduced CD8⁺ T cell-mediated induction of IP-10 and IL-6 responses in U251 astrocytes but had no effect on MCP-1. THC treatment differentially affected T cell effector functions such that IFNγ and degranulation responses were sensitive to THC-mediated ablation while TNFα was not. Lastly, THC treatment reduced the IFNγ-induced IP-10 response but had no effect on TNFα-induced MCP-1 response in U251 astrocytes. The results suggest that cannabinoid treatment can selectively reduce certain CD8⁺ T cell responses that contribute to stimulation of astrocytes.

Treatment with THC can abate CD8⁺ T cell-dependent neuroinflammatory processes by inhibiting CD8⁺ cell differentiation into effector cells, suppressing CD8⁺ effector cell function, and reducing activation of astrocytes by CD8⁺ T cell-derived inflammatory cytokines.

     

Environmental nitrogen dioxide (NO2) exposure influences development and progression of ischemic stroke

Here the correlativity between NO₂, a representative pollutant of vehicle exhaust, and ischemic stroke was first determined under experimental conditions following some epidemiological reports. First, we found that blood viscosity, red blood cell (RBC) aggregation-, electrophoresis- and rigidity-index in healthy rats were increased after exposure to 5 mg/m³ NO₂ for one- and three-month. Based on this, we set up stroke rat model and exposed them to NO₂ at the same concentration for one week, and found that NO₂ exposure time-dependently delayed neurological structure and function recovery of MCAO (middle cerebral artery occlusion) rat, and worsened pathological injuries and apoptosis induced by MCAO operation. Endothelial and inflammatory responses, two common cellular pathomechanisms involved in ischemic brain damage, were induced in cortex by MCAO treatment and exacerbated by followed NO₂ inhalation. Expression of the endothelial and inflammatory biomarkers in stroke displayed the same tendency in healthy rats after sub-acute and sub-chronic NO₂ exposure as in MCAO model in a concentration-dependent manner. Our data provide evidence that environmental NO₂ is an important inducer, and also a promoter of ischemic stroke, with endothelial nitric oxide synthase (eNOS), cyclooxygenase-2 (COX-2) and intercellular adhesion molecule 1 (ICAM-1) being potential indicators of this effect.     

Osthole attenuates focal inflammatory reaction following permanent middle cerebral artery occlusion in rats

Osthole,a main active constituent from Cnidium monnieri(L.) Cusson,has been considered therapeutic agent in the treatment of ischemic stroke.This study was designed to investigate the effect of osthole on permanent middle cerebral artery occlusion(MCAO) in rats.Osthole was administrated by gavage to the normal and the MCAO rats.Rats were assessed for neurological deficit after 24 h following MCAO,then their brains were evaluated to determine the infarct area,and the mRNA and protein levels of some inflammatory factors were detected.It was found that MCAO animals pre-treated with osthole for 7 d showed significant improvement in all neurological tests compared with vehicle-treated MCAO groups.In addition,there was a significant decrease in infarct volume 24 h after occlusion in animals pre-treated with osthole versus the vehicle-treated MCAO group.MCAO also dramatically caused some inflammatory factors increase.However,pretreatment with osthole restored the mRNA and protein levels of these factors,including TNF-α,IL-1β,COX-2,iNOS of ischemic penumbra cortices,suggesting that osthole possessed the function of preventing brain against ischemic damage,while no significant difference was found in any of normal groups with or without osthole.The present study demonstrated that osthole may be a novel neuroprotective therapy in the treatment of focal ischemic stroke.     

Low dose methamphetamine mediates neuroprotection through a PI3K-AKT pathway

High doses of methamphetamine induce the excessive release of dopamine resulting in neurotoxicity. However, moderate activation of dopamine receptors can promote neuroprotection. Therefore, we used in vitro and in vivo models of stroke to test the hypothesis that low doses of methamphetamine could induce neuroprotection. We demonstrate that methamphetamine does induce a robust, dose-dependent, neuroprotective response in rat organotypic hippocampal slice cultures exposed to oxygen-glucose deprivation (OGD). A similar dose dependant neuroprotective effect was observed in rats that received an embolic middle cerebral artery occlusion (MCAO). Significant improvements in behavioral outcomes were observed in rats when methamphetamine administration delayed for up to 12 h after MCAO. Methamphetamine-mediated neuroprotection was significantly reduced in slice cultures by the addition of D1 and D2 dopamine receptor antagonist. Treatment of slice cultures with methamphetamine resulted in the dopamine-mediated activation of AKT in a PI3K dependant manner. A similar increase in phosphorylated AKT was observed in the striatum, cortex and hippocampus of methamphetamine treated rats following MCAO. Methamphetamine-mediated neuroprotection was lost in rats when PI3K activity was blocked by wortmannin. Finally, methamphetamine treatment decreased both cleaved caspase 3 levels in slice cultures following OGD and TUNEL staining within the striatum and cortex in rats following transient MCAO. These data indicate that methamphetamine can mediate neuroprotection through activation of a dopamine/PI3K/AKT-signaling pathway.     

Involvement of IL-1beta in acute stress-induced worsening of cerebral ischaemia in rats.

Stress is known to be one of the risk factors of stroke. Most of the knowledge on the effects of stress on cerebrovascular disease in humans is restricted to catecholamines and glucocorticoids effects on blood pressure and/or development of atherosclerosis. However, few experimental studies have examined the possible mechanisms by which stress may affect stroke outcome. We have used an acute stress protocol consisting of the exposure of male Fischer rats to an acute, single exposure immobilisation protocol (6 h) prior to permanent middle cerebral artery occlusion (MCAO), and we have found that stress worsens behavioural and neurological outcomes and increased infarct size after MCAO. The possible regulatory role of the TNFalpha and IL-1beta was studied by looking at the release of these cytokines in brain. The results of the present study showed an increase in IL-1beta release in cerebral cortex after exposure to acute stress. Brain levels of IL-1beta are also higher in previously stressed MCAO rats than in MCAO animals without stress. Pharmacological blockade of IL-1beta with an antibody anti-IL-1beta led to a decrease in the infarct size as well as in neurological and behavioural deficits after MCAO. In summary, our results indicate that IL-1beta, but not TNFalpha, accounts at least partly for the worsening of MCAO consequences in brain of rats exposed to acute stress.     

Targeting Brain-spleen Crosstalk After Stroke: New Insights Into Stroke Pathology and Treatment

The immune response following acute stroke has received significant attention. The spleen is an important immune organ, and more and more studies have shown that brain-spleen crosstalk after stroke plays an important role in its development and prognosis. There are many mechanisms of spleen activation after stroke, including activation of the sympathetic nervous system, the production of chemokines, and antigen presentation in the damaged brain. The changes in the spleen after stroke are mainly reflected in morphology, changes to immune cells, and cytokine production. Once activated, the spleen contracts, undergoes cellular changes, and releases inflammatory cytokines. Some studies have also shown that spleen cells specifically migrate to the site of primary brain injury. The size of the spleen is also negatively correlated with infarct volume — the more serious the spleen atrophy, the larger the infarct volume. Therefore, a comprehensive understanding of the dynamic response of the spleen to stroke will not only enable understanding of the evolution of ischemic brain injury but will also enable the identification of potential targets for stroke treatment. Here, we review recent basic and clinical drug studies on the spleen as a target for the treatment of stroke, focusing on therapeutic strategies for regulating the splenic response and inhibiting secondary brain injury.     

Protection by the gross saponins of Tribulus terrestris against cerebral ischemic injury in rats involves the NF-κB pathway

The aim of this study was to investigate whether the gross saponins of Tribulus terrestris (GSTT), a traditional Chinese herbal medicine, have neuroprotective effects on rats subjected to middle cerebral artery occlusion (MCAO), through nuclear factor-κB (NF-κB) pathway and inflammatory mediators. Cerebral ischemia was produced by MCAO in either untreated (control) or GSTT-pretreated rats, and the animals were examined for infarct volume, cerebral edema, neuro-behavioral abnormality and pathological changes. Meanwhile, the expression of NF-κB protein in brain tissue was analyzed on Western blots and the serum levels of TNF-α and IL-1 were determined by ELISA. The experimental results demonstrated that, compared with the control MCAO group, GSTT-pretreated MCAO group had significantly reduced infarct volume, brain edema and neuro-behavioral abnormality, and lesser degree of pathologic changes in the brain, as well as had lower levels of serum TNF-α and IL-1β, and higher levels of brain NF-κB (P<0.05). Furthermore, treatment with an NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) abolished the protective effects of GSTT against MCAO-induced cerebral ischemic injury. These results indicated that GSTT's ability to protect against cerebral ischemic injury was mediated through the NF-κB signaling pathway, and that GSTT may act through inhibition of the production of inflammatory mediators.     

Myrrh extract alleviated ROS-mediated ferroptosis through regulating TXNIP/NLRP3 axis in ischemic stroke

OBJECTIVE To investigate the neuroprotective effects and exact mechanisms of myrrh extract following cerebral ischemic stroke. METHODS Male rats were randomly divided into three groups: sham group, middle cerebral artery occlusion(MCAO) group and myrrh group. Morphological changes were assessed after 7 d of myrrh treatment.Microarray analysis with circulating mRNA was performed to identify differential gene expression profile, gene ontology and pathway enrichment analyses were carried out to predict the gene function. Gene co-expression and pathway networks were constructed to identify the potential targets. The markers of oxidative stress, inflammatory reaction and ferroptosis in the cerebral cortex were detected by ELISA assays. The identified hub pathways and genes were validated by western blotting, immunofluorescence and immunohistochemistry analyses. Neurons were exposed to transient oxygen-glucose deprivation(OGD) to model ischemia-like conditions. si RNA-TXNIP were transfected in OGD-induced neurons to explore the mechanism. RESULTS Myrrh extract significantly alleviated neurological deficits, infarct volume and histopathological damage in MCAO rats. A total of 2200 differentially expressed genes were identified among the three groups. Oxidation-reduction process, inflammatory response, ferroptosis were enriched as the significant gene ontology items. NOD-like receptor signaling were identified as the hub pathway based on the pathway relation network. TXNIP and NLRP3 were screened as the potential targets by a time sequence profile analysis. The levels of IL~(-1)β, IL~(-1)8, TNF-α,MDA and TFR in brain tissues were increased while the CAT, SOD, GSH-px and GPX4 levels were significantly decreased in MCAO group. As expected, myrrh extract greatly reversed these changes. The similarly results were also observed in OGD treated neuron cells. The elevated expressions of TXNIP and NLRP3 induced by OGD were successfully inhibited by myrrh treatment. Knockdown of TXNIP significantly alleviated OGD-induced ROS accumulation and oxidative stress, but the antioxidative effect of myrrh was impaired when TXNIP was absent in neuron cells. In addition,knockdown of TXNIP significantly decreased the expression of NLRP3 and increased the expression of GPX4 in OGDinduced neuron cells. However, myrrh treatment scarcely changed the expressions of NLRP3 and these ferroptosis markers in si RNA-TXNIP pretreated cells, compared with the si RNA-TXNIP alone treatment group. Therefore, these data demonstrated that the neuroprotective effect of myrrh extract was dependent on TXNIP-NLRP3 axis. CONCLUSION Thatmyrrh extract exerts neuroprotective property through alleviated ROS-mediated ferroptosis by regulating the TXNIP/NLRP3 axis in ischemic stroke. Myrrh extract could be considered as a promising candidate for the treatment of ischemic stroke.     

Luteoloside attenuates neuroinflammation in focal cerebral ischemia in rats via regulation of the PPARγ/Nrf2/NF-κB signaling pathway

Luteoloside, a flavonoid compound, has been reported to have anti-inflammatory, anti-oxidative, antibacterial, antiviral, anticancer, and cardioprotective effects, among others, but its neuroprotective effects have rarely been studied. The purpose of this study was to investigate the protective effect of luteoloside on cerebral ischemia and explore its potential mechanism. Middle cerebral artery occlusion (MCAO) was performed to investigate the effects of luteoloside on cerebral ischemia-reperfusion (I/R). Male Sprague-Dawley rats were randomly divided into six groups: sham, MCAO, luteoloside (20 mg/kg, 40 mg/kg, 80 mg/kg) and nimodipine (4 mg/kg). The results showed that luteoloside alleviated neurologic deficits and cerebral edema as well as improved cerebral infarction and histopathological changes in MCAO rats. Luteoloside significantly inhibited I/R-induced neuroinflammation, as demonstrated by reduced levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the brain tissues of MCAO rats. Furthermore, our results demonstrated that luteoloside significantly suppressed the activation of nuclear factor-kappa B (NF-κB) signaling, upregulated the protein expression of peroxisome proliferator activated receptor gamma (PPARγ) and increased NF-E2-related factor (Nrf2) nuclear accumulation in MCAO rats. Collectively, our findings suggested that luteoloside played a crucial neuroprotective role by inhibiting NF-κB signaling in focal cerebral ischemia in rats. Furthermore, PPARγ and Nrf2 were also important for the anti-inflammatory effect of luteoloside. In addition, our data suggested that luteoloside might be an effective treatment for cerebral ischemia and other neurological disorders.     

2-Methoxystypandrone ameliorates brain function through preserving BBB integrity and promoting neurogenesis in mice with acute ischemic stroke

2-Methoxystypandrone (2-MS), a naphthoquinone, has been shown to display an immunomodulatory effect in a cellular model. To explore whether 2-MS could protect mice against cerebral ischemic/reperfusion (I/R)-induced brain injury, we evaluated 2-MS's protective effects on an acute ischemic stroke by inducing a middle cerebral artery occlusion/reperfusion (MCAO) injury in murine model. Treatment of mice that have undergone I/R injury with 2-MS (10–100 μg/kg, i.v.) at 2 h after MCAO enhanced survival rate and ameliorated neurological deficits, brain infarction, neural dysfunction and massive oxidative stress, due to an enormous production of free radicals and breakdown of blood–brain barrier (BBB) by I/R injury; this primarily occurred with extensive infiltration of CD11b-positive inflammatory cells and upexpression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 and p65 nuclear factor-kappa B (NF-κB). All of these pathological changes were diminished by 2-MS; 2-MS also intensively limited cortical infarction and promoted upexpression of neurodevelopmental genes near peri-infarct cortex and endogenous neurogenesis near subgranular zone of hippocampal dentate gyrus and the subventricular zone, most possibly by inactivation of GSK3β which in turn upregulating β-catenin, Bcl-2 adam11 and adamts20. We conclude that 2-MS blocks inflammatory responses by impairing NF-κB signaling to limit the inflammation and oxidative stress for preservation of BBB integrity; 2-MS also concomitantly promotes neurodevelopmental protein expression and endogenous neurogenesis through inactivation of GSK3β to enhance β-catenin signaling for upexpression of neuroprotective genes and proteins.     

Lactobacillus plantarum strain YU from fermented foods activates Th1 and protective immune responses

Lactic acid bacteria (LAB) are known to have effects on immune function. From 203 strains of LAB isolated from fermented foods, we selected a beneficial strain, Lactobacillus plantarum strain YU (LpYU), which has high interleukin (IL)-12-inducing activity in mouse peritoneal macrophages. This activity of LpYU was partially mediated by Toll-like receptor (TLR) 2, but not TLR4 or TLR9. Oral administration of LpYU to ovalbumin (OVA)-immunized mice caused suppression of serum OVA-specific immunoglobulin E (IgE) levels, enhancing interferon (IFN)-γ production from spleen cells in response to OVA. Furthermore, LpYU enhanced natural killer cell activity in spleen cells and the production of IgA from Peyer's patch cells. Because activation of Th1 immune responses and IgA production induce antiviral effects, we evaluated the inhibitory effects of LpYU against the influenza A virus (A/NWS/33, H1N1) (IFV). Oral administration of LpYU suppressed viral proliferation in the lungs and in bronchoalveolar lavage fluids (BALFs). Both levels of IFV-specific secretory IgA in BALF and feces and titers of IFV-specific neutralizing antibody in BALFs and sera were increased. These results indicate that LpYU has a protective effect against IFV replication. We conclude that this strain has a beneficial effect in activating Th1 immune responses and preventing viral infection.     

Lactobacillus plantarum strain YU from fermented foods activates Th1 and protective immune responses

Lactic acid bacteria (LAB) are known to have effects on immune function. From 203 strains of LAB isolated from fermented foods, we selected a beneficial strain, Lactobacillus plantarum strain YU (LpYU), which has high interleukin (IL)-12-inducing activity in mouse peritoneal macrophages. This activity of LpYU was partially mediated by Toll-like receptor (TLR) 2, but not TLR4 or TLR9. Oral administration of LpYU to ovalbumin (OVA)-immunized mice caused suppression of serum OVA-specific immunoglobulin E (IgE) levels, enhancing interferon (IFN)-γ production from spleen cells in response to OVA. Furthermore, LpYU enhanced natural killer cell activity in spleen cells and the production of IgA from Peyer's patch cells. Because activation of Th1 immune responses and IgA production induce antiviral effects, we evaluated the inhibitory effects of LpYU against the influenza A virus (A/NWS/33, H1N1) (IFV). Oral administration of LpYU suppressed viral proliferation in the lungs and in bronchoalveolar lavage fluids (BALFs). Both levels of IFV-specific secretory IgA in BALF and feces and titers of IFV-specific neutralizing antibody in BALFs and sera were increased. These results indicate that LpYU has a protective effect against IFV replication. We conclude that this strain has a beneficial effect in activating Th1 immune responses and preventing viral infection.     

木犀草素抑制JAK2/STAT3信号通路减轻大鼠脑缺血 再灌注损伤作用的研究

目的 观察木犀草素减轻大鼠脑缺血再灌注损伤的作用并探讨其潜在机制。方法 SD大鼠按随机数字 表法分为假手术组、大脑中动脉栓塞（MCAO）组、木犀草素低剂量组（50 mg/kg）、木犀草素高剂量组（100 mg/kg）及尼 莫地平组（15 mg/kg）,灌胃给药,共7 d。采用线栓法建立MCAO大鼠模型,比较神经功能损伤评分、脑组织含水量、 脑梗死体积,测定各组肿瘤坏死因子α（TNF-α）、白细胞介素（IL）-6、IL-1β、B细胞淋巴瘤因子2（Bcl-2）、Bcl-2相关 X蛋白（Bax）、半胱氨酸蛋白酶3（Caspase-3）含量及磷酸化Janus蛋白酪氨酸激酶2（p-JAK2）、磷酸化信号转导及转 录激活蛋白3（p-STAT3）蛋白表达等变化情况。结果 与假手术组比较,MCAO组大鼠神经功能损伤评分、脑组织含 水量、脑梗死体积、脑组织TNF-α、IL-6、IL-1β、Bax、Caspase-3含量及JAK2、STAT3蛋白磷酸化水平均明显增加（P＜ 0.05）,而脑组织Bcl-2含量明显降低（P＜0.05）;与MCAO组比较,木犀草素低、高剂量组及尼莫地平组大鼠神经功能 损伤评分、脑组织含水量、脑梗死体积、脑组织TNF-α、IL-6、IL-1β、Bax、Caspase-3含量及JAK2、STAT3蛋白磷酸化 水平均明显降低（P＜0.05）,而脑组织Bcl-2含量明显增加（P＜0.05）。结论 木犀草素具有减轻大鼠脑缺血再灌注 损伤的作用,该作用与抑制JAK2/STAT3信号通路活化,进而减弱炎症反应及减少细胞凋亡有关。     

异丙酚对大鼠局灶性脑缺血和蛋白激酶C γ亚单位的作用

目的观察异丙酚对大鼠局灶性脑缺血和脑内蛋白激酶Cγ亚单位(PKCγ)变化的作用。方法♂SD大鼠随机分为Ⅰ:假手术组,Ⅱ:损伤组,Ⅲ:异丙酚(25mg·kg-1)+损伤组,Ⅳ:异丙酚(50mg·kg-1)+损伤组,Ⅴ:脂肪乳剂+损伤组,每组8例。采用大脑中动脉线栓法缺血3h再灌注24h。异丙酚和脂肪乳剂于再灌注前30min腹腔注射。通过原位末端脱氧核苷酸转移酶标记法观察局灶性脑缺血产生的神经细胞凋亡和异丙酚作用效果,免疫细胞化学法观察各组PKCγ蛋白在脑内表达变化的差异。结果再灌注24h后Ⅱ、Ⅲ、Ⅳ、Ⅴ组大鼠体重较缺血前降低(P<0.01),和Ⅰ组比较:Ⅱ、Ⅲ、Ⅳ、Ⅴ组大鼠再灌注24h后出现明显的神经体征缺陷(P<0.01),Ⅱ组大鼠额叶皮层和纹状体区域大量神经细胞凋亡,纹状体PKCγ蛋白表达明显下降。Ⅱ、Ⅲ、Ⅳ、Ⅴ组大鼠纹状体区域凋亡细胞密度与PKCγ染色阳性面积均没有差异(P>0.05)。结论再灌注前30min腹腔注射异丙酚对大鼠局灶性脑缺血再灌注损伤所致的神经细胞凋亡和PKCγ表达降低无保护作用。     

Selective downregulation of N-methyl-D-aspartate receptor (NMDAR) rather than non-NMDAR subunits in ipsilateral cerebral hemispheres in rats with middle cerebral artery occlusion

Ischemic brain damage is believed to involve the drastic increase in extracellular glutamate levels after reperfusion and subsequent overactivation of both N-methyl-D-aspartate (NMDA) receptor (NMDAR) and non-NMDAR channels for delayed neuronal cell death mediated by Ca2+ overload. In this study, we evaluated expression profiles of mRNA and corresponding proteins for different subunits of NMDAR and non-NMDAR in brains of rats with transient middle cerebral artery occlusion (MCAO). Cellular vitality was markedly reduced in proportion to increasing durations of MCAO for 1 to 8 h when determined 1 day after reperfusion. Within 7 days after reperfusion, MCAO for 2 h led to a gradual decrease in the neuronal marker microtubules-associated protein-2 (MAP2) level in the ipsilateral cerebral hemisphere, in addition to inducing a transient increase in the microglial marker CD11b expression without affecting the astroglial marker protein levels. MCAO for 2 h significantly decreased the expression of both mRNA and corresponding proteins for NR1, NR2A and NR2B subunits of NMDAR, but not for non-NMDAR subunits, in the ipsilateral hemisphere. These results suggest that NMDAR may be preferentially down-regulated in response to ischemic signal inputs amongst three different subtypes of ionotropic glutamate receptors in rats with MCAO.     

Icariin attenuates cerebral ischemia–reperfusion injury through inhibition of inflammatory response mediated by NF-κB,PPARα and PPARγ in rats

Icariin (ICA), an active flavonoid extracted from Chinese medicinal herb Epimedii, has been reported to exhibit many pharmacological effects including alleviating brain injury. However, little is known about the protection of ICA on ischemic stroke. Hence, this study was designed to investigate the neuroprotective effect of ICA and explore its underlying mechanisms on ischemic stroke induced by cerebral ischemia–reperfusion (I/R) injury in rats. The animals were pretreated with ICA at doses of 10, 30 mg/kg twice per day for 3 consecutive days followed by cerebral I/R injury induced by middle cerebral artery occlusion (MCAO) for 2 h and reperfusion for 24 h. Neurological function and infarct volume were observed at 24 h after reperfusion, the protein expression levels of interleukin-1β (IL-1β), transforming growth factor-β₁ (TGF-β₁), PPARα and PPARγ, inhibitory κB-α (IκB-α) degradation and nuclear factor κB (NF-κB) p65 phosphorylation were detected by Western blot, respectively. It was found that pretreatment with ICA could decrease neurological deficit score, diminish the infarct volume, and reduce the protein levels of IL-1β and TGF-β₁. Moreover, ICA suppressed IκB-α degradation and NF-κB activation induced by I/R. Furthermore, the present study also showed that ICA up-regulated PPARα and PPARγ protein levels. These findings suggest that ICA has neuroprotective effect on ischemic stroke in rats through inhibition of inflammatory responses mediated by NF-κB and PPARα and PPARγ.     

丹酚酸B对脑缺血再灌注大鼠神经细胞损伤和神经发生的影响

本文旨在观察丹酚酸B对脑缺血再灌注大鼠神经发生和神经细胞损伤的影响，探讨丹酚酸B促进机体功能恢复的作用环节。研究采用大鼠局灶性脑缺血再灌注模型，治疗给药，用BrdU法观察海马齿状回颗粒下层(sub-granular zone，SGZ)和侧脑室下层(sub-ventricular zone，SVZ)神经发生的变化；尼氏体染色观察神经细胞损伤；平衡杆法观察肢体功能恢复。结果显示，缺血后再灌注7 d，模型组SGZ和SVZ的BrdU细胞明显多于假手术组(P<0.05)，丹酚酸B(10 mg·kg^-1)显著增加SGZ和SVZ的BrdU细胞数目(P<0.01 vs模型组)；缺血再灌注14 d，模型动物缺血侧海马CA1区和皮层神经细胞明显减少，丹酚酸B(10 mg·kg^-1)明显改善神经细胞损伤(P<0.01 vs模型组)；同时，丹酚酸B(10 mg·kg^-1)明显促进缺血动物肢体功能恢复。以上结果表明，丹酚酸B能够增加脑缺血大鼠SVZ和SGZ的BrdU细胞数目，改善缺血区神经细胞损伤，促进肢体功能恢复，提示促进神经发生是丹酚酸B改善脑功能的重要环节。     

Matrilin-3 is found in brain and promotes brain functional recovery in rats ischemic stroke via targeting astrocytes

OBJECTIVE To explore the role of matrilin-3(MATN-3) in ischemic stroke and its underlying mechanisms. METHODS Adult male Sprague Dawley rats randomly treated with either overexpression MATN-3(LV-MATN-3) or control lentiviruses were subjected to transient middle cerebral artery occlusion(t MCAO) for90 min. Primary neurons or astrocytes were exposed to oxygen-glucose deprivation(OGD) or OGD/reoxygenation(OGD/Re) in the absence or presence of LV-MATN-3 or MATN-3 sh RNA, or necrostatin-1, a specific inhibitor of RIPK1(receptor interacting protein kinase 1). Stroke size, neurological deficit, brain atrophy, glial scar, cell death, MATN-3, RIPK1, pro-inflammatory cytokines and BMP-2/Smads pathway were evaluated. RESULTS MATN-3 is rich in rat′s and human brain. Aftert MCAO,MATN-3 protein levels were declined in the ischemic core of cerebral cortex with time from day 3 of reperfusion, while in the peri-infarct area, MATN-3 was elevated in the reactive astrocytes at day 7 of reperfusion. Similarly,MATN-3 levels were up-regulated in OGD/Re-induced reactive astrocytes. In contrast, there were no obvious changes in MATN-3 in OGD/Re-induced neuronal cell injury. Knockdown of MATN-3 induced or aggravated OGD-induced astrocytic cel death, but showed no obvious influence on neuronal cell death. However, overexpression of MATN-3 decreased OGD/Re-induced astrocytic cell death, reduced cerebral infarct volume, improved neurological deficits, attenuated glial scar formation and brain atrophy, and suppressed BMP-2/Smads pathway,pro-inflammatory cytokines and RIPK1 in reactive astrocytes. Importantly, RIPK1 linked BMP-2/Smads pathway and pro-inflammatory cytokine. Additionally, autophagy regulated the synthesis and secretion of MATN-3 in astrocytes. CONCLUSION MATN-3 is required for astrocytes, but not for neurons. Overexpression of MATN-3 improves ischemic stroke outcome by protecting astrocytes and attenuating the glial scar formation via suppressing RIPK1 linked BMP-2/Smads pathway and pro-inflammatory response.     

齐多夫定肉豆蔻酯脂质体与齐多夫定对实验动物毒性作用比较研究

目的研究齐多夫定肉豆蔻酯脂质体与齐多夫定对实验动物的毒性作用。方法采用昆明种小鼠,观察两种剂型药物的急性LD50。将昆明种小鼠分成3组,观察两种剂型药物对小鼠的行为活动、体重以及脏器系数的影响。采用Bagle犬分成3组,观察两种剂型药物对犬的行为活动、体重、脏器系数、血液学指标、血清生化值、脏器病理的影响。结果AZT组的LD50为12.50mg·kg^-1,AZT-ML组的LD50为20.30mg·kg^-1。AZT-ML组小鼠的行为活动基本正常,其体重、脏器系数的改变较AZT组明显减轻。AZT-ML组犬的行为活动基本正常、其体重、脏器系数、血液学指标、血清生化值、脏器病理的改变较AZT组明显减轻。结论与AZT相比,AZT-ML对实验动物机体的损害及毒性作用显著降低。