脂肪组织巨噬细胞极化在慢性炎症中的作用及调控机制

巨噬细胞广泛存在于各个组织中，在机体发育、体内平衡、组织修复和人体自身免疫等多个环节中扮演重要角色。巨噬细胞与多种疾病的炎症反应密切相关，应激条件下可极化为M1促炎型和M2抗炎型，尤其是在肥胖相关的代谢性疾病中，脂肪组织巨噬细胞极化具有重要的临床意义。本文综述脂肪组织巨噬细胞极化在慢性炎症中的作用及调控机制，尝试为相关研究提供理论支持。     

巨噬细胞极化对心肌成纤维细胞活化的影响

目的 观察巨噬细胞极化上清对心肌成纤维细胞活化的影响。方法 提取SD大鼠的骨髓细胞和心肌成 纤维细胞。利用巨噬细胞集落刺激因子（M-CSF）处理骨髓细胞后,加入刺激因子：M0（无刺激因子）、M1（100 μg/L脂 多糖+10 μg/L干扰素-γ）、M2（20 μg/L白细胞介素-4）诱导巨噬细胞极化。将极化后的不同型别巨噬细胞及其培养 上清分别与心肌成纤维细胞共培养,分别设空白对照组、M0组、M1组和M2组,通过细胞免疫荧光检测心肌成纤维细 胞中纤维化蛋白的表达水平;实时荧光定量逆转录聚合酶链反应检测巨噬细胞和成纤维细胞特征分子的表达; Western blot检测纤维化相关蛋白及转化生长因子β受体（TGFβR）、血小板衍生生长因子受体（PDGFRs）信号通路活 化情况。结果 经M-CSF及相应刺激因子诱导,成功获得M1和M2型巨噬细胞。细胞共培养结果显示,与M0组相 比,M1组上清培养的心肌成纤维细胞中胶原蛋白1（Col1a1）和Col3a1的mRNA水平以及平滑肌肌动蛋白（α-SMA）表 达水平显著降低（P＜0.05）,而M2组上清培养的心肌成纤维细胞中Col1a1和Col3a1的mRNA水平以及α-SMA、结缔 组织生长因子（CCN2）表达水平显著升高（P＜0.05）。M1组上清培养的心肌成纤维细胞中PDGFRβ蛋白磷酸化水平 显著低于 M0 组（P＜0.01）,而 M2 组上清培养的心肌成纤维细胞中 PDGFRβ 蛋白磷酸化水平显著高于 M0 组（P＜ 0.05）。结论 M1型巨噬细胞上清能够抑制心肌成纤维细胞活化,而M2型巨噬细胞上清能够激活心肌成纤维细胞。 M1型巨噬细胞抑制纤维化的作用可能与抑制PDGFRβ通路的活化有关。     

巨噬细胞极化在动脉粥样硬化中的作用和药物靶标

动脉粥样硬化(atherosclerosis)是一个复杂的代谢性心血管疾病,在动脉内膜局部脂质入侵积聚、泡沫细胞增多、炎性病变加剧、粥样斑块坏死和崩解、溃疡出血和血栓形成、纤维组织增生和钙化等炎症现象为基本特征的病理变化。而在此过程中,巨噬细胞和T淋巴细胞起到重要作用。巨噬细胞不同亚型极化及其作用是近年来动脉粥样硬化病理研究的热点,巨噬细胞主要分为经典活化的巨噬细胞M1和替代性活化的巨噬细胞M2两个亚型。因此,该文将对动脉粥样硬化中巨噬细胞M1和M2型极化作用意义、调控途径和药物靶标的研究状况进行综述,为新的创新药物开发和疾病治疗提供新的思考方向。     

骨髓间充质干细胞来源外泌体对炎症微环境中巨噬细胞 表型及软骨细胞的调控作用

目的 研究骨髓间充质干细胞来源外泌体（BMSCs-Exo）在炎症微环境中对巨噬细胞表型极化及软骨修复的调控作用。方法 差速离心法提取BMSCs-Exo，透射电镜观察外泌体形态，Western blot检测Alix、TSG101表达；使用不同浓度的BMSCs-Exo（10 μg/mL 和50 μg/mL）处理M1巨噬细胞及IL-1β刺激的软骨细胞，CCK-8测定BMSCs-Exo促巨噬细胞增殖能力，Western blot和qRT-PCR验证BMSCs-Exo对M1型巨噬细胞表型极化的影响，炎症相关基因IL-1β、IL-6的表达水平，以及成软骨相关因子COL II、MMP-13、TGF-β1的表达水平。结果 BMSCs-Exo为圆形双层囊泡，表达Alix、TSG101，可促进巨噬细胞增殖。与对照组比较，M1型巨噬细胞经BMSCs-Exo处理后，M1型极化标记物（iNOS）的表达水平降低，M2型极化标记物（Arg-1）的表达水平升高（P<0.05）；炎症相关基因IL-1β、IL-6的表达水平显著降低（P<0.05），炎症软骨细胞中的COL II、TGF-β1表达升高，MMP-13表达水平降低（P<0.05）。结论 BMSCs-Exo可调控M1型巨噬细胞向M2型巨噬细胞极化，降低炎症因子表达水平，促进炎症微环境中软骨修复。     

通心络对巨噬细胞极化的影响

目的研究通心络对巨噬细胞向M2、M1型极化的影响及其对Notch信号通路的作用。方法采用PMA分别联合IL-4、LPS诱导THP-1细胞分别向M2、M1型巨噬细胞极化并给予通心络进行干预,检测其标志分子IL-10、TNF-α、IL-6的表达及巨噬细胞极化相关Notch信号通路蛋白的表达。结果 M2组细胞培养上清中IL-10水平升高,IL-6、TNF-α的水平差异无统计学意义;M1组细胞培养上清中IL-10水平明显降低,IL-6、TNF-α水平明显升高;通心络组细胞培养上清中IL-10水平升高,IL-6、TNF-α水平下降。M2组细胞active Notch-1、DLL4、Hes-1蛋白表达与对照组比较差异无统计学意义,M1组细胞active Notch-1、DLL4、Hes-1蛋白表达明显升高,通心络组细胞active Notch-1、DLL4、Hes-1蛋白表达明显降低,各组Notch-1蛋白表达差异无统计学意义。结论通心络可抑制巨噬细胞向M1型极化,其机制可能与抑制Notch-1信号通路活化有关。     

白细胞介素4和白细胞介素13与M2型肺泡巨噬细胞在肺纤维化中的作用研究进展

2型辅助性T细胞(Th2)是CD4+T细胞经抗原刺激后分化的细胞群,其分泌的白细胞介素4(IL-4)/IL-13作用于巨噬细胞,使其经"替代激活"活化为M2型巨噬细胞,从而发挥特定作用;肺组织在受到抗原持续刺激后,存在于肺泡及间充质中的巨噬细胞在经Th2细胞分泌的IL-4和IL-13激活形成M2型肺泡巨噬细胞,从而参与肺纤维化(PF)的进程,可见M2肺泡巨噬细胞在PF中起着重要的作用。本综述以PF为背景,探讨Th2型细胞因子IL-4和IL-13在PF中的作用,M2型肺泡巨噬细胞的抗炎和促纤维化作用,IL-4和IL-13受体在治疗PF中的作用,IL-4和IL-13激活的M2型肺泡巨噬细胞对PF的双重作用,为抗PF药物研究提供思路。     

MSCs 通过调控巨噬细胞极化维持 TBI 后免疫稳态的研究进展

摘要： 间充质干细胞 （MSCs） 是当前细胞治疗的研究热点, 其不仅具有多向分化潜能, 还能够调节颅脑创伤 （TBI）后组织损伤引发的炎症反应。继发于单纯机械损伤的神经炎症是引起神经细胞坏死和凋亡的重要因素, 即使在颅内压恢复正常后, 炎症反应仍持续造成神经细胞坏死。创伤后的炎症环境严重影响 TBI 患者的长期预后及行为功能恢复。MSCs 通过释放可溶性细胞因子, 如前列腺素 E2 （PGE2）、 肿瘤坏死因子刺激基因 6 蛋白 （TSG-6）、 白细胞介素 （IL） -1 和转化生长因子 （TGF） -β 等, 调节巨噬细胞/小胶质细胞的极化特性, 使其向抗炎型 M2 细胞极化, 减少促炎因子释放, 限制其对下游效应细胞的激活, 维持颅内免疫环境稳定。同时, MSCs 在一定条件下促进巨噬细胞/小胶质细胞向 M1 细胞极化, 激活组织修复和再生。巨噬细胞/小胶质细胞形成的免疫微环境也影响 MSCs 的存活和功能发挥, 两者相互影响, 为临床治疗TBI 继发炎症反应提供了新的思路。     

肿瘤相关巨噬细胞对肿瘤转移的影响及靶向治疗的研究进展

肿瘤相关巨噬细胞是肿瘤微环境的重要组成部分,单核巨噬细胞系统具有可塑性,在不同的诱导条件和刺激因素下,肿瘤相关巨噬细胞可极化为M1和M2型巨噬细胞。M2型巨噬细胞对肿瘤的发生和发展有重要的作用,巨噬细胞可对抗肿瘤治疗,通过调节肿瘤细胞的活化,促进肿瘤血管生长,抑制自体T细胞增殖和γ干扰素的产生,使T细胞失去抗肿瘤活性,通过释放细胞因子等促进肿瘤细胞转移。肿瘤相关巨噬细胞的靶向治疗,主要通过抑制巨噬细胞的募集,抑制肿瘤相关巨噬细胞的生存,调节巨噬细胞的极化,调节肿瘤微环境中的巨噬细胞,从而影响肿瘤的生存和转移。     

DHA虾青素双酯抑制脂肪细胞与巨噬细胞共培养体系中炎症反应

摘要：目的 在体外水平研究DHA虾青素双酯对脂肪组织炎症的改善作用并探究其作用机制。方法 采用Transwell小室法建立脂肪细胞与巨噬细胞共培养体系,模拟体内脂肪组织炎症状态,检测培养上清中炎症因子水平以及游离脂肪酸和甘油含量,油红O染色观察脂肪细胞脂解情况,免疫荧光表征巨噬细胞极化情况,qRT-PCR测定脂肪细胞脂解与巨噬细胞极化相关基因表达。结果 DHA虾青素双酯能显著降低共培养体系中促炎因子TNF-α（P<0.01）和MCP-1（P<0.05）的水平;抑制脂肪细胞脂解,降低培养上清中甘油含量（P<0.05）;促进巨噬细胞向M2型极化,显著降低巨噬细胞内M1型标志基因IL-1β、INOS的表达（P<0.01）;并且显著抑制脂肪细胞脂解相关基因TNFR（P<0.01）、JNK（P<0.01）、G0S2（P<0.05）、ATGL（P<0.01）和NF-κB信号通路关键基因MyD88、NF-κB及TNF-α（P<0.01）的表达。结论 DHA虾青素双酯可降低脂肪细胞与巨噬细胞共培养体系中炎症因子分泌,抑制脂肪细胞脂解、促进巨噬细胞M2型极化,最终抑制共培养体系中的炎症反应。     

中介素通过激活AMPK信号通路对脂多糖诱导巨噬细胞极化的影响

目的探讨中介素(intermedin,IMD)对脂多糖(lipopolysaccharide,LPS)诱导小鼠单核巨噬细胞系RAW 264.7极化的影响及其作用机制。方法RAW 264.7细胞随机分为对照组、LPS组、LPS+IMD组、LPS+IMD+CC(AMPK抑制剂Compound C)组。Real time-PCR法检测TNF-α、CD86、iNOS、Arg^-1、CD206 mRNA表达,Western blot法检测p-AMPK、AMPK、TNF-α、IL-6和IL^-10蛋白表达,流式细胞术检测巨噬细胞亚型,ELISA法检测培养基上清IL-6和TNF-α浓度。结果与对照组及LPS组比较,IMD处理可增加AMPK磷酸化水平,增加p-AMPK/AMPK比值;与对照组相比,LPS诱导可导致巨噬细胞发生M1极化,M1型标志分子CD86、TNF-α及iNOS mRNA表达升高,M2型标志分子CD206、Arg^-1 mRNA表达降低,上调促炎因子TNF-α、IL-6表达,降低抑炎因子IL^-10表达,使M1型细胞数量增加,细胞上清中TNF-α、IL-6分泌增加;而IMD处理可抑制LPS诱导的M1极化,AMPK抑制剂Compound C组处理可在一定程度上拮抗这一作用。结论IMD通过激活AMPK信号通路抑制LPS诱导的巨噬细胞M1型极化。     

Biomimetic carbon monoxide delivery based on hemoglobin vesicles ameliorates acute pancreatitis in mice via the regulation of macrophage and neutrophil activity

Macrophages play a central role in various inflammatory disorders and are broadly divided into two subpopulations, M1 and M2 macrophage. In the healing process in acute inflammatory disorders, shifting the production of M1 macrophages to M2 macrophages is desirable, because M1 macrophages secrete pro-inflammatory cytokines, whilst the M2 variety secrete anti-inflammatory cytokines. Previous findings indicate that when macrophages are treated with carbon monoxide (CO), the secretion of anti-inflammatory cytokine is increased and the expression of pro-inflammatory cytokines is inhibited, indicating that CO may have a potential to modulate the production of macrophages toward the M2-like phenotype. In this study, we examined the issue of whether CO targeting macrophages using a nanotechnology-based CO donor, namely CO-bound hemoglobin vesicles (CO-HbV), modulates their polarization and show therapeutic effects against inflammatory disorders. The results showed that the CO-HbV treatment polarized a macrophage cell line toward an M2-like phenotype. Furthermore, in an in vivo study using acute pancreatitis model mice as a model of an inflammatory disease, a CO-HbV treatment also tended to polarize macrophages toward an M2-like phenotype and inhibited neutrophil infiltration in the pancreas, resulting in a significant inflammation. In addition to the suppression of acute pancreatitis, CO-HbV diminished a subsequent pancreatitis-associated acute lung injury. This could be due to the inhibition of the systemic inflammation, neutrophil infiltration in the lungs and the production of HMGB-1. These findings suggest that CO-HbV exerts superior anti-inflammatory effects against inflammatory disorders via the regulation of macrophage and neutrophil activity.     

Combination therapy using microwave ablation and d-mannose-chelated iron oxide nanoparticles inhibits hepatocellular carcinoma progression

Despite being a common therapy for hepatocellular carcinoma (HCC), insufficient thermal ablation can leave behind tumor residues that can cause recurrence. This is believed to augment M2 inflammatory macrophages that usually play a pro-tumorigenic role. To address this problem, we designed d-mannose-chelated iron oxide nanoparticles (man-IONPs) to polarize M2-like macrophages into the antitumor M1 phenotype. In vitro and in vivo experiments demonstrated that man-IONPs specifically targeted M2-like macrophages and accumulated in peri-ablation zones after macrophage infiltration was augmented under insufficient microwave ablation (MWA). The nanoparticles simultaneously induced polarization of pro-tumorigenic M2 macrophages into antitumor M1 phenotypes, enabling the transformation of the immunosuppressive microenvironment into an immunoactivating one. Post-MWA macrophage polarization exerted robust inhibitory effects on HCC progression in a well-established orthotopic liver cancer mouse model. Thus, combining thermal ablation with man-IONPs can salvage residual tumors after insufficient MWA. These results have strong potential for clinical translation.     

Inflammatory mechanisms in myocardial infarction

Myocardial infarction is associated with an inflammatory response, ultimately leading to healing and scar formation. Reperfused myocardial infarcts exhibit an enhanced inflammatory reaction, and are associated with improved cardiac repair and patient survival. This review summarizes our current knowledge of the inflammatory mechanisms mediating injury and repair following myocardial ischemia and reperfusion. Myocardial necrosis is associated with complement activation and free radical generation, triggering a cytokine cascade and chemokine upregulation. Interleukin (IL)-8 and C5a are released in the ischemic myocardium, and may have a crucial role in neutrophil recruitment. Extravasated neutrophils may induce potent cytotoxic effects through the release of proteolytic enzymes and the adhesion with Intercellular Adhesion Molecule (ICAM)-1 expressing cardiomyocytes. However, despite these potentially injurious effects, the post-reperfusion inflammatory response may significantly enhance healing. Monocyte Chemoattractant Protein (MCP)-1 is induced in the infarcted area and may regulate mononuclear cell recruitment. Accumulation of monocyte-derived macrophages, and mast cells may increase expression of growth factors inducing angiogenesis and fibroblast accumulation in the infarct. In addition, expression of cytokines inhibiting the inflammatory response, such as Interleukin (IL)-10 may suppress injury. Matrix Metalloproteinases (MMPs) and their inhibitors regulate extracellular matrix deposition and play an important role in mediating ventricular remodeling. Inflammatory mediators may induce recruitment of blood-derived primitive stem cells in the healing infarct, which may differentiate into endothelial cells and even lead to limited myocardial regeneration. Understanding the cellular and molecular steps involved in regulating infarct healing may lead to specific interventions aimed at optimizing cardiac repair.     

CSF-1R inhibition attenuates ischemia-induced renal injury and fibrosis by reducing Ly6C+ M2-like macrophage infiltration

Acute kidney injury (AKI) to chronic kidney disease (CKD) progression has become a life-threatening disease. However, an effective therapeutic strategy is still needed. The pathophysiology of AKI-to-CKD progression involves chronic inflammation and renal fibrosis driven by macrophage activation, which is physiologically dependent on colony-stimulating factor-1 receptor (CSF-1R) signaling. In this study, we modulated macrophage infiltration through oral administration of the CSF-1R inhibitor GW2580 in an ischemia–reperfusion (I/R)-induced AKI model to evaluate its therapeutic effects on preventing the progression of AKI to CKD. We found that GW2580 induced a significant reduction in the number of macrophages in I/R-injured kidneys and attenuated I/R-induced renal injury and subsequent interstitial fibrosis. By flow cytometry, we observed that the reduced macrophages were primarily Ly6C⁺ inflammatory macrophages in the GW2580-treated kidneys, while there was no significant difference in the number and percentage of Ly6C⁻CX3CR1⁺ macrophages. We further found that these reduced macrophages also demonstrated some characteristics of M2-like macrophages, which have been generally regarded as profibrotic subtypes in chronic inflammation. These results indicate the existence of phenotypic and functional crossover between Ly6C⁺ and M2-like macrophages in I/R kidneys, which induces AKI worsening to CKD. In conclusion, therapeutic GW2580 treatment alleviates acute renal injury and subsequent fibrosis by reducing Ly6C⁺ M2-like macrophage infiltration in ischemia-induced AKI.     

Tramadol differentially regulates M1 and M2 macrophages from human umbilical cord blood

Tramadol is an analgesic drug and relieves pain through activating μ-opioid receptors and inhibiting serotonin and noradrenaline reuptake. Emerging evidence shows that it also stimulates immune cells, including NK cells, splenocytes, and lymphocytes, and elevates IL-2 production. However, it remains unknown whether and how tramadol directly affects macrophages. To answer these questions, we collected human umbilical cord blood, isolated macrophages, and examined their responses to tramadol. Although tramadol did not alter resting macrophages and the antigen-presenting function in lipopolysaccharide-activated macrophages, it regulated M1 and M2 macrophages, which are, respectively, transformed by IFN-γ and IL-4. Interestingly, tramadol inhibits production and secretion of cytokines in M1 macrophages, but facilitates the production of inflammation-responding molecules, synthesized in M2 macrophages. We also found that STAT6 cascade pathway in M2 macrophages was significantly enhanced by tramadol. Therefore, this study reveals that tramadol regulates inflammation by inhibiting M1 macrophages (killing process), but promoting the function of M2 macrophages (healing process).     

Protective effects of M40403, a selective superoxide dismutase mimetic,in myocardial ischaemia and reperfusion injury in vivo

1. Myocardial injury caused by ischaemia and reperfusion comes from multiple pathogenic events, including endothelial damage, neutrophil extravasation into tissue, mast cell activation, and peroxidation of cell membrane lipids. These events are followed by myocardial cell alterations resulting eventually in cell necrosis. An enhanced formation of reactive oxygen species is widely accepted as a stimulus for tissue destruction and cardiac failure. 2. In this study, we have investigated the cardioprotective effects of M40403 in myocardial ischaemia-reperfusion injury. M40403 is a low molecular weight, synthetic manganese containing superoxide dismutase mimetic (SODm) that selectively removes superoxide anion. Ischaemia was induced in rat hearts in vivo by ligating the left anterior descending coronary artery. Thirty minutes after the induction of ischaemia, the ligature was removed and reperfusion allowed to occur for at least 60 min. M40403 (0.1-1 mg kg(-1)) was given intravenously 15 min before ischaemia. 3. The results obtained in this study showed that M40403 significantly reduced the extent of myocardial damage, mast cell degranulation and the incidence of ventricular arrhythmias. Furthermore, M40403 significantly attenuated, in a dose-dependent manner, neutrophil infiltration in the myocardium as well as the associated induction of lipid peroxidation. Calcium overload seen post-reperfusion of the ischaemic myocardium was also reduced by M40403. 4. Immunohistochemical analysis for nitrotyrosine revealed a positive staining in cardiac tissue taken after reperfusion: this was attenuated by M40403. Moreover reperfused cardiac tissue sections showed positive staining for P-selectin and for anti-intercellular adhesion molecule (ICAM-1) in the vascular endothelial cells. M40403 treatment markedly reduced the intensity and degree of P-selectin and ICAM-1 in these tissues. No staining for nitrotyrosine, P-selectin or ICAM-1 was found in cardiac tissue taken at the end of the ischaemic period. 5. Overall, M40403 treatment reduced the morphological signs of myocardial cell injury and significantly improved survival. 6. Taken together, these results clearly indicate that M40403 treatment exerts a protective effect against ischaemia-reperfusion-induced myocardial injury, supporting a key role for superoxide anion in reperfusion injuries. This suggests that synthetic enzymes of SOD such as M40403, offer a novel therapeutic approach for the treatment of ischaemic heart disease where superoxide anion plays a dominant role.     

The role of the chemokines in myocardial ischemia and reperfusion

Chemokines critically regulate basal and inflammatory leukocyte trafficking and may play a role in angiogenesis. This review summarizes our current understanding of the regulation and potential role of the chemokines in myocardial ischemia and reperfusion. Reperfused myocardial infarction is associated with an inflammatory response leading to leukocyte recruitment, healing and scar formation. Neutrophil chemoattractants, such as the CXC chemokine CXCL8/Interleukin (IL)-8, are upregulated in the infarcted area inducing polymorphonuclear leukocyte infiltration. In addition, mononuclear cell chemoattractants, such as the CC chemokine CCL2/Monocyte Chemoattractant Protein (MCP)-1, are expressed, leading to monocyte and lymphocyte recruitment in the ischemic area. However, chemokines may have additional effects in healing infarcts beyond their leukotactic properties. We have recently described a marked transient induction of the angiostatic CXC chemokine CXCL10/Interferon-gamma inducible Protein (IP)-10 in the infarct. Upregulation of angiostatic factors, such as IP-10, in the first few hours following injury may inhibit premature angiogenesis, until the infarct is debrided and appropriate supportive matrix is formed. Suppression of IP-10 synthesis during the healing phase may allow formation of the wound neovessels, a critical process for infarct healing. Chemokine expression is also noted after a single brief ischemic insult in the absence of myocardial infarction, suggesting a potential role for a chemokine-induced inflammatory response in noninfarctive ischemic cardiomyopathy. Unlike cytokines, which have pleiotropic effects, chemokines have more specific cellular targets. Understanding of their role in myocardial infarction may allow us to design specific therapeutic strategies aiming at optimizing cardiac repair and preventing ventricular remodeling.     

Pseudoginsenoside-F11 ameliorates ischemic neuron injury by regulating the polarization of neutrophils and macrophages in vitro

Pseudoginsenoside-F11 (PF11), an ocotillol-type saponin, has neuroprotective effects on permanent and transient cerebral ischemia in rats by alleviating autophagic/lysosomal defects and repressing calcium overload, respectively. Ischemic stroke triggers peripheral innate immune cells, mainly neutrophils and macrophages, to infiltrate the damaged brain. The polarization of neutrophils and macrophages after cerebral ischemia is essential for post-stroke damage/recovery. However, it remains elusive whether PF11 ameliorates ischemic neuron injury by regulating the polarization of neutrophils and macrophages. The present study demonstrated for the first time that conditioned media from ischemic neurons induced neutrophils and macrophages to polarize into N1 and M1 phenotypes, respectively. Furthermore, PF11 (30, 100 μM) inhibited the induction of N1 neutrophils by conditioned media from oxygen glucose deprivation/re-oxygenation (OGD/R)-induced ischemic neurons and promoted the polarization of neutrophils to N2 phenotypes. In addition, PF11 (100 μM) attenuated the exacerbation of N1 neutrophils and facilitated the protection of N2 neutrophils on OGD/R-induced neuronal damage. Similarly, PF11 (100 μM) inhibited the induction of M1 macrophages by conditioned media from ischemic neurons and facilitated the polarization of macrophages to M2 phenotypes. What's more, PF11 (100 μM) attenuated the aggravation of M1 macrophages and promoted the protection of M2 macrophages on OGD/R-induced primary neuron injury. In summary, the present study indicates that PF11 ameliorates ischemic neuron damage by regulating neutrophils and macrophages polarization, suggesting that neutrophils and macrophages may be promising targets for the treatment of cerebral ischemia.     

Inhibitory effect of dibutyryl chitin ester on nitric oxide and prostaglandin E2 production in LPS-stimulated RAW 264.7 cells

Inflammation is a highly complex process that protects against foreign challenge or tissue injury. The ester derivative dibutyryl chitin (DBC) reportedly accelerates wound healing and exerts an anti-inflammatory effect. However, little is known regarding the inhibitory effect of DBC in anti-inflammation. In this study, we investigated the effect of DBC on the inducible nitric oxide synthetase (iNOS) and cyclooxygenage-2 (COX-2) pathways and pro-inflammatory cytokine production in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. Our results demonstrate that DBC (MW 3,772) significantly inhibits overproduction of NO and PGE(2) as well as pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-1β, in LPS-stimulated RAW 264.7 macrophages. Inhibition of NO and PGE(2) overproduction in LPSstimulated RAW 264.7 macrophages by DBC was mediated through the down-regulation of iNOS and COX-2 expression. These results demonstrate that DBC efficiently inhibits inflammation and has potential as an effective anti-inflammatory and wound healing agent.