泮托拉唑对急性肺损伤模型大鼠和人肺微血管内皮细胞损伤的作用及作用机制

目的 探讨泮托拉唑对急性肺损伤(ALI)模型大鼠和人肺微血管内皮细胞(HPMECs)损伤的作用及作用机制.方法 将48只SD大鼠随机分为正常对照组,脂多糖组,阳性对照组,泮托拉唑低、高剂量组和泮托拉唑高剂量+氯喹组,各8只.除正常对照组外,其余各组大鼠均腹腔注射5 mg/kg脂多糖复制ALI模型;阳性对照组大鼠腹腔注射...     

Tanshinone IIA attenuates seawater aspiration-induced lung injury by inhibiting macrophage migration inhibitory factor

Inflammation takes responsibility for the seawater aspiration-induced lung injury. Tanshinone IIA (TIIA) can protect lipopolysaccharide-induced lung injury in mice through the inhibition of inflammation, but it is not reported whether TIIA have a protective effect on lung injury induced by seawater aspiration. Macrophage migration inhibitory factor (MIF) plays an important role in acute lung injury. In this study, we observed the effect of TIIA on the seawater aspiration-induced lung injury and the role of MIF in it. Seawater was aspirated into trachea of rats to make the lung injury model. TIIA was administered to investigate its beneficial effect on seawater-induced acute lung injury. The results showed that seawater aspiration led to hyoxemia, pulmonary edema, neutrophil infiltration, and lung histopathologic changes, with the elevated MIF expression in the lung tissues and plasma. However, these changes were attenuated by TIIA. In macrophage cells we also demonstrated that TIIA could inhibit MIF expression, nuclear factor κB (NF-κB) activity and release of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) induced by seawater. Besides, pretreatment with (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid (ISO-1), the MIF antagonist, elevated NF-κB and cytokines induced by seawater were also reduced markedly. Furthermore, rMIF treatment alone increased the phosphorylation level of NF-κB and release of cytokines, which was almost abolished by TIIA. Taken together, our results suggested that TIIA exert a protective effect on the seawater aspiration-induced lung injury partly through downregulation of MIF and the subsequent NF-κB activity, as well as expression of IL-6 and TNF-α.     

Relevance of mitogen activated protein kinase (MAPK) and phosphotidylinositol-3-kinase/protein kinase B (PI3K/PKB) pathways to induction of apoptosis by curcumin in breast cells

Following observations that curcumin inhibited proliferation (IC(50)=1-5 microM), invasiveness and progression through S/G2/M phases of the cell cycle in the non-tumourigenic HBL100 and tumourigenic MDA-MB-468 human breast cell lines, it was noted that apoptosis was much more pronounced in the tumour line. Therefore, the ability of curcumin to modulate signalling pathways which might contribute to cell survival was investigated. After pre-treatment of cells for 20 min, curcumin (40 microM) inhibited EGF-stimulated phosphorylation of the EGFR in MDA-MB-468 cells and phosphorylation of extracellular signal regulated kinases (ERKs) 1 and 2, as well as ERK activity and levels of nuclear c-fos in both cell lines. At a lower dose (10 microM), it also inhibited the ability of anisomycin to activate JNK, resulting in decreased c-jun phosphorylation, although it did not inhibit JNK activity directly. In contrast, the activation of p38 mitogen activated protein kinase (MAPK) by anisomycin was not inhibited. Curcumin inhibited basal phosphorylation of Akt/protein kinase B (PKB) in both cell lines, but more consistently and to a greater extent in the MDA-MB-468 cells. The MAPK kinase (MKK) inhibitor U0126 (10 microM), while preventing ERK phosphorylation in MDA-MB-468 cells, did not induce apoptosis. The PI3K inhibitor LY294002 (50 microM) inhibited PKB phosphorylation in both cells lines, but only induced apoptosis in the MDA-MB-468 line. These results suggest that while curcumin has several different molecular targets within the MAPK and PI3K/PKB signalling pathways that could contribute to inhibition of proliferation and induction of apoptosis, inhibition of basal activity of Akt/PKB, but not ERK, may facilitate apoptosis in the tumour cell line.     

Protective effects of diphenyleneiodonium,an NADPH oxidase inhibitor,on lipopolysaccharide‐induced acute lung injury

NADPH oxidase (NOX) plays an important role in inflammatory response by producing reactive oxygen species (ROS). The inhibition of NOX has been shown to induce anti‐inflammatory effects in a few experimental models. The aim of this study was to investigate the effects of diphenyleneiodonium (DPI), a NOX inhibitor, on lipopolysaccharide (LPS)‐induced acute lung injury (ALI) in a rat model. Sprague‐Dawley rats were intraperitoneally administered by DPI (5 mg/kg) 30 minutes after intratracheal instillation of LPS (3 mg/kg). After 6 hours, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The NOX activity in lung tissue was significantly increased in LPS‐treated rats. It was significantly attenuated by DPI. DPI‐treated rats showed significant reduction in the intracellular ROS, the number of inflammatory cells, and cytokines (TNF‐α and IL‐6) in BALF compared with LPS‐treated rats. In lung tissue, DPI‐treated rats showed significantly decreased malondialdehyde content and increased activity of glutathione peroxidase and superoxide dismutase compared with LPS‐treated rats. Lung injury score, myeloperoxidase activity, and inducible nitric oxide synthase expression were significantly decreased in DPI‐treated rats compared with LPS‐treated animals. Western blotting analysis demonstrated that DPI significantly suppressed LPS‐induced activation of NF‐κB and ERK1/2 and SAPK/JNK in MAPK pathway. Our results suggest that DPI may have protective effects on LPS‐induced ALI thorough anti‐oxidative and anti‐inflammatory effects which may be due to inactivation of the NF‐κB, ERK1/2, and SAPK/JNK pathway. These results suggest the therapeutic potential of DPI as an anti‐inflammatory agent in ALI.     

右美托咪定激活PI3K/Akt通路改善LPS诱导的大鼠急性肺损伤实验研究

目的 考察右美托咪定（Dex）对脂多糖（LPS）诱导的大鼠急性肺损伤（ALI）的影响,并探讨可能与PI3K/Akt信号通路改变的相关机制。方法 将80只SD大鼠根据建模方法随机分为5组：对照组、模型组、Dex低剂量组、Dex高剂量组、Dex+LY294002组,建模24 h时处死并分离肺组织,观察组织病理切片,检查肺水肿程度及微血管通透性,采用Western blotting法检测Akt及其磷酸化蛋白以及线粒体凋亡信号相关蛋白的表达水平,检查线粒体细胞色素C、膜电位及ATP含量,并用电镜观察线粒体形态,采用流式细胞术检测肺组织细胞凋亡情况,采用DCFH-DA探针荧光显微镜法检测细胞内的活性氧（ROS）水平。结果 LPS滴注24 h后,病理切片表现有明显的ALI特征,Dex在50 μg/kg剂量时可明显改善LPS诱导的ALI病理特征;以对照组为参照,p-Akt（Thr308）与p-Akt（Ser473）的相对表达量模型组未发生明显变化,Dex组则均显著增高（P<0.001）,在Dex+LY294002组的表达水平较Dex组显著降低（P<0.001）;模型组的Bax与Bcl-2蛋白较对照组的相对表达量分别显著升高与降低（P<0.001）,Dex组分别降低与升高至接近对照组水平,Dex+LY294002组又分别回升与回降;对照组、模型组、Dex组、Dex+LY294002组的肺组织细胞凋亡率分别为2.4%、19.5%、6.7%、13.1%;各组的ROS水平变化与肺组织细胞凋亡情况一致性良好。结论 Dex可通过激活PI3K/Akt信号通路减轻LPS诱导的肺组织细胞凋亡及线粒体凋亡信号激活,继而改善ALI,发挥肺保护作用。     

Tanshinone IIA therapeutically reduces LPS-induced acute lung injury by inhibiting inflammation and apoptosis in mice

Aim:

To study the effects of tanshinone IIA (TIIA) on lipopolysaccharide (LPS)-induced acute lung injury in mice and the underlying mechanisms.

Methods:

Mice were injected with LPS (10 mg/kg, ip), then treated with TIIA (10 mg/kg, ip). Seven hours after LPS injection, the lungs were collected for histological study. Protein, LDH, TNF-α and IL-1β levels in bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) activity in lungs were measured. Cell apoptosis and Bcl-2, caspase-3, NF-κB and HIF-1α expression in lungs were assayed.

Results:

LPS caused marked histological changes in lungs, accompanied by significantly increased lung W/D ratio, protein content and LDH level in BALF, and Evans blue leakage. LPS markedly increased neutrophil infiltration in lungs and inflammatory cytokines in BALF. Furthermore, LPS induced cell apoptosis in lungs, as evidenced by increased TUNEL-positive cells, decreased Bcl-2 content and increased cleaved caspase-3 content. Moreover, LPS significantly increased the expression of NF-κB and HIF-1α in lungs. Treatment of LPS-injected mice with TIIA significantly alleviated these pathological changes in lungs.

Conclusion:

TIIA alleviates LPS-induced acute lung injury in mice by suppressing inflammatory responses and apoptosis, which is mediated via inhibition of the NF-κB and HIF-1α pathways.     

Brain-derived neurotrophic factor prevents phencyclidine-induced apoptosis in developing brain by parallel activation of both the ERK and PI-3K/Akt pathways

Phencyclidine is an N-methyl d-aspartate receptor (NMDAR) blocker that has been reported to induce neuronal apoptosis during development and schizophrenia-like behaviors in rats later in life. Brain-derived neurotrophic factor (BDNF) has been shown to prevent neuronal death caused by NMDAR blockade, but the precise mechanism is unknown. This study examined the role of the phosphatidylinositol-3 kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK) pathways in BDNF protection of PCP-induced apoptosis in corticostriatal organotypic cultures. It was observed that BDNF inhibited PCP-induced apoptosis in a concentration-dependent fashion. BDNF effectively prevented PCP-induced inhibition of the ERK and PI-3K/Akt pathways and suppressed GSK-3β activation. Blockade of either PI-3K/Akt or ERK activation abolished BDNF protection. Western blot analysis revealed that the PI-3K inhibitor LY294002 prevented the stimulating effect of BDNF on the PI-3K/Akt pathway, but had no effect on the ERK pathway. Similarly, the ERK inhibitor PD98059 prevented the stimulating effect of BDNF on the ERK pathway, but not the PI-3K/Akt pathway. Co-application of LY294002 and PD98059 had no additional effect on BDNF-evoked activation of Akt or ERK. However, concurrent exposure to PD98059 and LY294002 caused much greater inhibition of BDNF-evoked phosphorylation of GSK-3β at serine 9 than did LY294002 alone. Finally, either BDNF or GSK-3β inhibition prevented PCP-induced suppression of cyclic-AMP response element binding protein (CREB) phosphorylation. These data demonstrate that the protective effect of BDNF against PCP-induced apoptosis is mediated by parallel activation of the PI-3K/Akt and ERK pathways, most likely involves inhibition of GSK-3β and activation of CREB.     

地塞米松抑制哮喘大鼠肺组织p38蛋白激酶的表达

目的:探讨支气管哮喘大鼠肺组织p38蛋白激酶(p38 MAPK)表达的变化以及地塞米松对其影响.方法:复制大鼠哮喘模型,随机分成3组:正常对照组、哮喘对照组和地塞米松(DEX)干预组.分别采用酶联免疫吸附法(ELISA)和蛋白质印迹检测支气管肺泡灌洗液(BALF)IL-5含量和肺组织磷酸化p38 MAPK表达的变化,并观察气道阻力、BALF中EOS计数以及肺组织病理学变化.结果:哮喘对照组大鼠肺组织磷酸化p38 MAPK表达水平及气道阻力、BALF中IL-5含量和EOS计数均较正常对照组显著增加(P＜0.01);DEX干预组上述指标较哮喘对照组显著降低(P＜0.01),肺组织病理学损伤程度明显减轻.肺组织磷酸化p38 MAPK表达水平与气道阻力、BALF中IL-5含量和EOS计数之间分别呈显著正相关(r=0.77、0.63、0.65,P＜0.01).结论:p38 MAPK可能参与了支气管哮喘的发病过程.DEX对哮喘的治疗作用至少部分与抑制磷酸化p38 MAPK的表达有关.     

地塞米松对急性肺损伤大鼠肺组织细胞凋亡及Fas/FasL系统表达的影响

目的 探讨细胞凋亡与急性肺损伤的发生、发展的关系以及地塞米松在全身炎症反应及急性肺损伤(acute lung injury,ALI)中的作用机制及意义。方法 通过复制内毒素性大鼠ALI模型、采用TUNEL法、原位杂交、SaRT-PCR以及免疫组化等技术观察ALI肺组织细胞凋亡的变化、Fas/FasL系统mRNA和蛋白表达的改变以及地塞米松对细胞凋亡及Fas、FasL表达的影响。结果 ALI早期肺组织细胞凋亡明显增加:Fas、FasL mRNA和蛋白质表达明显上调,地塞米松可明显抑制大鼠ALI血清TNFα释放、抑制肺部炎症反应;明显抑制LPS诱导的肺组织细胞凋亡,并明显下调Fas、FasL mRNA和蛋白质的表达。结论 肺组织细胞凋亡及Fas/FasL系统表达上调,可能参与大鼠ALI早期的发病机制;地塞米松可通过抑制炎症介质释放,抑制Fas/FasL系统的活化,阻断、调控肺组织靶细胞调亡,而减轻肺组织损伤。     

细胞外信号调节激酶通路对大鼠再灌注损伤肺细胞凋亡的影响

目的：探讨大鼠肺缺血/再灌注损伤时磷酸化细胞外信号调节激酶（ERK）蛋白表达的变化及其意义。方法：30只SD大鼠随机分为三组：假手术对照（C组）,肺缺血/再灌注（I/R组）,肺缺血/再灌注＋PD98059（P组）;测定血清丙二醛（MDA）含量、超氧化物岐化酶（SOD）活力,免疫组化法检测磷酸化ERK蛋白的表达;TUNEL法检测肺组织细胞凋亡的改变;电镜观察肺组织形态学改变。结果：I/R组与C组比较,MDA含量明显增加（P〈0.01）,SOD活力明显下降（P〈0.01）,P-ERK蛋白表达明显上调（P〈0.01）,凋亡指数（AI）显著增高（P〈0.01）,肺组织超微结构明显异常;使用ERK通路特异性抑制剂-PD98059后,MDA含量进一步升高（P〈0.01）,SOD活力进一步下降（P〈0.05）,P-ERK蛋白表达明显下调（P〈0.01）,AI进一步增加（P〈0.01）,肺组织超微结构异常改变继续加重。结论：ERK信号转导通路可能参与了拮抗再灌注肺细胞凋亡,对肺缺血/再灌注损伤发挥积极的防治作用。     

Inhibition of the MAP kinase ERK protects from lipopolysaccharide-induced lung injury

The pathogenesis of chronic obstructive pulmonary disease (COPD) is characterized by pulmonary inflammation associated with lung neutrophilia and elevated levels of pro-inflammatory mediators in the bronchoalveolar lavage fluid or sputum of patients. Recent findings revealed that mitogen-activated protein kinase (MAPK) signaling cascade is involved in the inflammatory response of lung injury. In the present study we could elucidate the role of extracellular signal-related MAPK in the murine model of LPS-induced acute lung injury by using U0126, a specific inhibitor of MEK1/2, upstream kinases of ERK. Phosphorylation of ERK was inhibited by U0126 in vivo as well as in vitro. In freshly isolated human peripheral blood mononuclear cells U0126 dose-dependently blocked the release of IL-2 and TNF-α. For in vivo studies mice were exposed to aerosolized LPS to induce an acute lung injury mimicking some aspects of COPD. This led to a recruitment of neutrophils to the lung and to the release of pro-inflammatory cytokines into bronchoalveolar lavage. Pretreatment of mice with U0126 significantly reduced lung neutrophilia and diminished levels of TNF-α and chemotactic MIP-2 and KC in bronchoalveolar fluid. U0126 also decreased albumin levels in BAL fluid, a marker of vascular leakage. Histological examination of lung tissues revealed that ERK MAPK inhibition using U0126 efficiently attenuated LPS-induced pulmonary inflammatory responses. These data suggest that ERK signaling plays an important role in acute lung injury and pharmacologic inhibition of ERK provides a promising new therapeutic strategy for lung inflammatory diseases and in particular COPD.     

Atorvastatin attenuates vascular remodelling in spontaneously hypertensive rats via the protein kinase D/extracellular signal-regulated kinase 5 pathway

The present study was conducted to determine whether atorvastatin reduces hypertension-induced vascular remodelling and whether its effects involve protein kinase D (PKD) and extracellular signal-regulated kinase 5 (ERK5). We used 16-week-old spontaneously hypertensive rats (SHRs) and age-matched Wistar-Kyoto (WKY) rats. The blood pressure and serum lipid concentration were measured. Changes in the vascular morphology and histology were examined using H&E, Masson^’s trichrome, and Sirius Red staining. The media thickness (MT), ratio of MT to lumen diameter (LD) (MT/LD), collagen volume fraction (CVF) and hydroxyproline content were measured to evaluate vascular remodelling. Atorvastatin (50 mg/kg/day) was administered for 8 weeks. Increased blood pressure and vascular remodelling were more prominent in SHRs than in WKY rats. SHRs also had elevated PKD and ERK5 activation. The systolic blood pressure, MT/LD ratio, and hydroxyproline content were positively correlated with the activation level of PKD and ERK5 in SHRs. Atorvastatin significantly attenuated the activation of PKD and ERK5. Overall, this study demonstrated that atorvastatin could reverse vascular remodelling in SHRs. The PKD/ERK5 signalling pathway might be important for elucidating the beneficial pleiotropic effects of atorvastatin on vascular remodelling.     

Tumor necrosis factor-α induced protein 6 attenuates acute lung injury following paraquat exposure

Context: Paraquat exposure commonly occurs in the developing countries and the mortality rate is high. However, there is currently no consensus on the efficacy of treatment for paraquat exposure.

Objective: The study was aimed to explore the effects of tumor necrosis factor-α (TNF-α) induced protein 6 (TSG-6) on acute lung injury (ALI) following paraquat exposure in rats.

Materials and methods: Male Sprague–Dawley (SD) rats were randomly divided into the sham group (n?=?8), the paraquat group (n?=?8), and the paraquat TSG-6-treated group (n?=?8). Rats were administered with 50?mg/kg of paraquat intraperitoneally. At 1?h after exposure, rats were treated with 30?μg of recombinant human TSG-6 (rhTSG-6) intraperitoneally. After 6?h of exposure, ALI scores were evaluated by histology and the expression of pro-inflammatory cytokines in lung was assayed using real-time RT-PCR.

Results: ALI scores were significantly lower in the paraquat TSG-6-treated group, compared with the paraquat group (p?<?0.05). The expression of interleukin (IL)-1β, IL-6, and TNF-α mRNA was significantly lower in the paraquat TSG-6-treated group, compared with the paraquat group (p?<?0.01, respectively).

Discussion and conclusion: Administration of rhTSG-6 attenuates ALI following paraquat exposure by suppressing inflammatory response.     

Reciprocal regulation of extracellular signal regulated kinase 1/2 and mitogen activated protein kinase phosphatase-3

Mitogen activated protein kinase phosphatase-3 (MKP-3) is a putative tumor suppressor. When transiently overexpressed, MKP-3 dephosphorylates and inactivates extracellular signal regulated kinase (ERK) 1/2. Little is known about the roles of endogenous MKP-3, however. We previously showed that MKP-3 is upregulated in cell lines that express oncogenic Ras. Here we tested the roles of endogenous MKP-3 in modulating ERK1/2 under conditions of chronic stimulation of the Ras/Raf/MEK1/2/ERK1/2 pathway by expression of oncogenic Ras. We used two cell lines: H-ras MCF10A, breast epithelial cells engineered to express H-Ras, and DLD-1, colon cancer cells that express endogenous Ki-Ras. First, we found that MKP-3 acts in a negative feedback loop to suppress basal ERK1/2 when oncogenic Ras stimulates the Ras/Raf/MEK1/2/ERK1/2 cascade. ERK1/2 was required to maintain elevated MKP-3, indicative of a negative feedback loop. Accordingly, knockdown of MKP-3, via siRNA, increased ERK1/2 phosphorylation. Second, by using siRNA, we found that MKP-3 helps establish the sensitivity of ERK1/2 to extracellular activators by limiting the duration of ERK1/2 phosphorylation. Third, we found that the regulation of ERK1/2 by MKP-3 is countered by the complex regulation of MKP-3 by ERK1/2. Potent ERK1/2 activators stimulated the loss of MKP-3 within 30 min due to an ERK1/2-dependent decrease in MKP-3 protein stability. MKP-3 levels recovered within 120 min due to ERK1/2-dependent resynthesis. Preventing MKP-3 resynthesis, via siRNA, prolonged ERK1/2 phosphorylation. Altogether, these results suggest that under the pressure of oncogenic Ras expression, MKP-3 reins in ERK1/2 by serving in ERK1/2-dependent negative feedback pathways.     

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。     

Activation of extracellular signal-regulated kinase during silibinin-protected, isoproterenol-induced apoptosis in rat cardiac myocytes is tyrosine kinase pathway-mediated and protein kinase C-dependent

Aim： To investigate the mechanism of silibinin-protected isoproterenol-induced apoptosis in rat cardiac myocytes. Methods： The viability of rat cardiac myocytes was measured by MTT method. The apoptotic ratio was measured by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling. Protein kinase C （PKC） activity assay was carried out according to the instructions of the PepTag non-radioactive protein kinase C assay kit. Western blot analysis was used to evaluate the level of Ras, Raf-1 and mitogen-activated protein kinase （MAPK） expression. Results： The protective effects of silibinin were significantly sup- pressed by inhibitors, including genistein, manumycin A and GW5074 [inhibitors for protein tyrosine kinases （PTK）, Ras and Raf- 1, respectively]. The exposure of rat cardiac myocytes to isoproterenol alone caused decreased PKC activity, which was prevented by pretreatment with silibinin dose-dependently. Simultaneously, the increased expression of Ras and Raf- 1 activated by silibinin were blocked by the PKC inhibitor, stauroporine. In addition, the extracellularly responsive kinase （ERK） inhibitor, PD98059, suppressed silibinin-protected apoptosis, whereas the p38 MAPK inhibitor, SB203580, protected cardiac myocytes from isoproterenolinduced injury, and the c-Jun N-terminal kinase （JNK） inhibitor, SP600125 had no protective effects. Furthermore, Westem blot analysis showed that the expres- sion of phosphorylated ERK was increased by silibinin, the expression of phos- phorylated p38 MAPK was decreased and total ERK, p38, JNK and phosphorylated JNK MAPK did not change after treatment with both isoproterenol and silibinin. Furthermore, pretreatment of cardiac myocyte with PKC, Ras and Raf inhibitors significantly blocked ERK phosphorylation. Conclusion： Silibinin is suggested to protect isoproterenol-induced rat cardiac myocyte apoptosis by activating the tyrosine kinase pathway, PKC and MAPK pathways.     

ODN2088减轻线粒体DNA致脓毒症大鼠急性肺损伤

目的:探讨血浆线粒体DNA(mtDNA)含量与脓毒症大鼠急性肺损伤(ALI)程度的关系及选择性TLR9受体抑制剂ODN2088对脓毒症大鼠ALI的保护作用.方法:按随机数表法将80只大鼠分为假手术(sham)组、脓毒症(sepsis)组、脓毒症大鼠腹腔注射mtDNA 1.4 mg/kg(sepsis+mtDNA)组、脓...     

丹参素通过抑制miR-199a-5p对心肌缺血再灌注损伤大鼠的保护作用

目的 评估丹参素对心肌缺血/再灌注(MI/R)损伤的保护作用及其可能机制.方法 32只大鼠随机分为假手术组、模型组组、丹参素30 mg/kg组和丹参素60 mg/kg组,丹参素组在再灌注开始后5 min内iv相应剂量丹参素,假手术组和模型组注射等量生理盐水;再灌注3 h后,向冠状动脉中注入2 mL的3％伊文思蓝染料;取...     

Apocynin ameliorates endotoxin-induced acute lung injury in rats

Acute lung injury (ALI) is a serious clinical syndrome with a high rate of mortality. In this study, the effects of apocynin, a NADPH-oxidase (NOX) inhibitor on lipopolysaccharide (LPS)-induced ALI in rats were investigated. Male Sprague–Dawley rats were treated with apocynin (10 mg/kg) intraperitoneally (i.p.) 1 h before LPS injection (10 mg/kg, i.p.). The results revealed that apocynin attenuated LPS-induced ALI as it decreased total protein content, lactate dehydrogenase (LDH) activity and the accumulation of the inflammatory cells in the bronchoalveolar lavage fluid (BALF), In addition, apocynin significantly increased superoxide dismutase (SOD) and reduced glutathione (GSH) activities with significant decrease in the lung malondialdehyde (MDA) content as compared to LPS group in lung tissue and decreased pulmonary artery contraction induced by LPS. It also upregulated mRNA expression of inhibitory protein kappaB-alpha (NFκBia) and downregulated mRNA expression of Toll-Like receptor 4 (TLR4) and decreased inflammation observed in lung tissues.Collectively, these results demonstrate the protective effects of apocynin against the LPS-induced ALI in rats through its antioxidant and antiinflammatory effect that may be attributed to the decrease in mRNA expression of TLR4 and increasing that of NFκBia.     

Protective effects of luteolin against lipopolysaccharide-induced acute lung injury involves inhibition of MEK/ERK and PI3K/Akt pathways in neutrophils

Aim:

To investigate whether luteolin, the major polyphenolic components of Lonicera japonica, has beneficial effects against lipopolysaccharide (LPS)-induced acute lung injury (ALI) and to determine whether the protective mechanism involves anti-inflammatory effects on neutrophils.

Methods:

ALI was induced with intratracheal instillation of LPS in mice. The level of ALI was determined by measuring the cell count and protein content in bronchoalveolar lavage (BAL) fluid. Neutrophils were stimulated with formyl-Met-Leu-Phe (fMLP) or LPS in vitro. Chemotaxis and superoxide anion generation were measured to evaluate neutrophil activation. The potential involvement of intracellular signaling molecules in regulating neutrophil activation was analyzed by using Western blot.

Results:

LPS induced ALI in mice, as evidenced with leukocyte infiltration and protein leakage into the lungs. Luteolin attenuated LPS-induced leukocyte infiltration and protein extravasation. In cell studies, luteolin attenuated the fMLP-induced neutrophil chemotaxis and respiratory burst (IC₅₀ 0.2±0.1 μmol/L and 2.2±0.8 μmol/L, respectively), but had a negligible effect on superoxide anion generation during phorbol myristate acetate stimulation. Furthermore luteolin effectively blocked MAPK/ERK kinase 1/2 (MEK), extracellular signal-regulated kinase (ERK), and Akt phosphorylation in fMLP- and LPS-stimulated neutrophils.

Conclusion:

These results indicate that luteolin has beneficial effects against LPS-induced ALI in mice, and the attenuation of neutrophil chemotaxis and respiratory burst by luteolin involves the blockade of MEK-, ERK-, and Akt-related signaling cascades.