姜黄素对视网膜缺血再灌注损伤大鼠IL-17、IL-23、IL-1β、TNF-α及NF-κB表达的影响

目的:研究不同剂量姜黄素对视网膜缺血再灌注损伤(RIRI)大鼠白细胞介素-17(IL-17)、白细胞介素-23(IL-23)、白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)及核转录因子-κB(NF-κB)表达的影响。方法:选取60只健康的SPF级雄性SD大鼠,将大鼠随机分为正常对照组(NC组)、模型组(M组)、姜黄素低剂量组(LC组)和姜黄素高剂量组(HC组),均为15只。M组、LC组和HC组大鼠的右眼均利用前房灌注法制备成RIRI模型,NC组进行正常喂养。模型制备前30 min和造模成功后每日定时给LC组和HC组腹腔分别注射30 mg/kg和120 mg/kg的姜黄素进行干预,NC组和M组则在同一时间腹腔注射适量的生理盐水。建模72h后显微镜下观察四组大鼠视网膜的组织形态,采用酶联免疫吸附法检测四组大鼠视网膜组织中IL-17、IL-23、IL-1β和TNF-α的水平,利用免疫组化法分析四组大鼠视网膜组织中NF-κB的表达情况。结果:NC组大鼠视网膜组织形态正常,M组、LC组和HC组大鼠视网膜组织形态均呈现出不同程度的病理性损伤,损伤程度排序为HC组LC组M组。M组IL-17、IL-23、IL-1β和TNF-α水平均高于HC组、LC组和NC组,LC组IL-17、IL-23、IL-1β和TNF-α水平均高于HC组和NC组,而HC组高于NC组(P0.05)。M组NF-κB表达的OD值高于HC组、LC组和NC组,LC组NF-κB表达的OD值高于HC组和NC组,而HC组高于NC组(P0.05)。结论:RIRI与炎症反应的增强及NF-κB的激活有关,姜黄素可有效降低RIRI的炎性因子水平,抑制NF-κB的激活,从而减轻RIRI的病理损伤和保护视网膜,且其保护作用在一定范围内与姜黄素的剂量呈正相关。     

RNA干扰NF-κB p65对缺血再灌注损伤鼠肺NF-κB和TNF-α的影响

为了研究RNA干扰NF-κBp65对鼠肺缺血再灌注损伤肺组织中NF-κB、TNF-α表达的影响,并探讨减轻鼠肺损伤的保护机制。本研究构建了体外靶向NF-κBp65的短发夹RNA (short hairpin RNA, shRNA)重组表达载体,并采用QPCR检测NF-κBp65的沉默结果。供试的16只SD大鼠随机分为4组:假手术组4只、缺血再灌注+生理盐水组4只,缺血再灌注+NF-κBp65 sh RNA组4只,缺血再灌注+空载组4只,假手术组无缺血再灌注损伤,开胸游离左肺门180 min,缺血再灌注+生理盐水组左肺门阻断前术前24 h给予生理盐水处理,开胸游离左肺门,左肺缺血60 min,再灌注120 min,缺血再灌注+NF-κBp65 shRNA组左肺门阻断前术前24 h滴鼻给予NF-κB shRNA腺病毒(1×1010pfu, 100μL/只),开胸游离左肺门,左肺缺血60 min,再灌注120 min,缺血再灌注+空载组左肺门阻断前术前24 h滴鼻给予空载shRNA腺病毒(1×10~(10)pfu, 100μL/只),开胸游离左肺门,左肺缺血60 min,再灌注120 min。实验结束后每组分别留取左肺组织,留取左肺上叶肺组织测定肺湿/干重比(W/D),部分肺组织光镜下观察病理变化,ELISA法测量NF-κB和TNF-α的表达含量。研究结果表明:成功构建重组NF-κBp65载体,并获得稳定转染的NF-κBp65 shRNA细胞,与转染空载体的阴性对照组(negative control, NC)比较,NF-κBp65 sh RNA能明显使NF-κBp65基因沉默(p0.05),肺组织NF-κB、TNF-α的表达量及W/D值与假手术组比较,缺血再灌注+生理盐水组和缺血再灌注+空载组有明显升高(p0.05);而与缺血再和灌注+生理盐水组和缺血再灌注+空载组比较,缺血再灌注+NF-κBp65 shRNA组明显降低(p0.05),病理学检查表明:假手术组肺组织无明显的炎症损伤;缺血再灌注+NF-κBp65 shRNA组肺炎性损伤较缺血再灌注+生理盐水组和缺血再灌注+空载组明显减轻。本研究结果初步说明,RNA干扰NF-κBp65能明显减轻早期肺移植损伤,其机制可能与抑制NF-κB和TNF-α的表达从而减轻肺组织炎症损伤有关。     

美洛昔康对Aβ诱导Alzheimer’s disease大鼠脑内炎症损伤的影响

目的：研究美洛昔康对β-淀粉样蛋白（Aβ）诱导的阿尔茨海默病（AD）模型大鼠脑内炎症损伤的保护作用,并探讨其抑制炎症作用的机制。方法：Aβ1-40海马注射建立AD大鼠模型。免疫组化法观察大鼠海马核因子κBp65（NF-κBp65）和星形胶质细胞（AS）胶质纤维酸性蛋白（GFAP）表达变化;Western-blot法测定大鼠皮层组织GFAP的表达;ELISA法检测大鼠皮层组织肿瘤坏死因子-α（TNF-α）水平变化;RT-PCR法检测大鼠海马组织白细胞介素-1β（IL-1β）mRNA的表达情况。结果：美洛昔康能抑制AD大鼠海马NF-κBp65和GFAP的表达;降低大鼠皮层TNF-α的含量;抑制AD大鼠海马IL-1βmRNA的表达。结论：美洛昔康通过减少AD模型大鼠海马、皮层组织GFAP表达,抑制AS的增生,降低NF-κBp65的活性,减少炎症因子TNF-α和IL-1β的水平,减轻脑内炎症反应。     

TLR7在1型糖尿病大鼠肾缺血再灌注损伤中的作用研究

目的:探讨Toll样受体7(TLR7)介导的My D88/NF-κB信号通路在1型糖尿病大鼠肾缺血再灌注损伤中的作用。方法:雄性SD大鼠随机分为3组(n=6),糖尿病假手术组(DS),糖尿病缺血再灌注组(DIR),糖尿病缺血再灌注+氯喹预处理组(DIR+CQ)。采用腹腔注射链尿佐菌素65 mg/kg建立糖尿病模型,TLR7抑制剂氯喹预处理于糖尿病模型成功后第3周0.5%氯喹40 mg/kg进行腹腔注射,连续给药7天。于第四周采用双侧肾蒂夹闭25 min,再灌注48 h建立肾缺血再灌注损伤模型。取大鼠肾脏HE染色观察大鼠病理学结果,血标本测定血尿素氮(BUN)和血肌酐(Scr)水平,ELISA法检测白细胞介素6(IL-6)和肿瘤坏死因子-α(TNF-α),TUNEL法检测细胞凋亡,Western blot检测TLR7,My D88和NF-κB蛋白表达。结果:与DS组相比,DIR组肾小管肿胀,间质水肿,刷状缘丢失,空泡变性坏死,Paller评分升高(P0.01)。与DIR组相比,氯喹预处理可以改善肾损伤(P=0.017);与DS组相比,DIR组BUN,Scr,IL-6,TNF-α,细胞调亡指数(Apoptosis%),TLR7,My D88,NF-κB增高(P0.05);与DIR组相比,DIR+CQ组BUN,Scr,IL-6,TNF-α,Apoptosis%,TLR7,My D88,NF-κB降低(P0.05)。结论:TLR7介导的My D88/NF-κB信号通路参与糖尿病肾缺血再灌注损伤,氯喹通过抑制TLR7表达,阻断My D88/NF-κB信号通路,降低炎症反应,从而减轻1型糖尿病大鼠肾缺血再灌注损伤。     

NF-κB激活在兔急性心肌梗死再灌注后无复流中的意义

目的:观察心肌核因子-κB(NF-κB)在急性心肌梗死(AMI)再灌注后无复流的活化情况,探讨NF-κB促进无复流发生发展的作用机制。方法:24只新西兰大白兔随机分为假手术组(冠状动脉只穿线不结扎)和缺血再灌注组(结扎冠状动脉2小时,再灌注1小时),每组12只。采用凝胶阻滞迁移分析方法(EMSA)检测正常区、缺血区和无复流区心肌组织中NF-κB活性;ELISA法测定不同时点血浆中白细胞介素-6(IL-6)、超敏C反应蛋白(CRP)以及肿瘤坏死因子-α(TNF-α)的含量;光镜、电镜观察心肌组织病理变化。结果:(1)与正常区相比,缺血区和无复流区心肌组织中NF-κB活性异常升高(P<0.01)。(2)与结扎前相比结扎后2h、再灌注后1h血浆IL-6、CRP、TNF-α水平呈进行性升高(P均<0.05)。(3)NF-κB的活性与无复流面积、血浆IL-6、CRP以及TNF-α水平呈正相关(分别为r=0.844,P<0.01;r=0.682,P<0.05;r=0.687,P<0.05;r=0.893,P<0.01)。(4)无复流面积与血浆IL-6、CRP以及TNF-α水平呈正相关(分别为r=0.861,P<0.01;...     

姜黄素干预油酸诱导的ALI/ARDS大鼠模型对NF-κB、TNF-α和IL-6的影响

急性肺损伤(acute lung injury,ALI)/急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)发病机制的大量研究表明核因子κB(nuclear factor kappa B,NF-κB)激活是其发生、发展的中心环节.姜黄素作为治疗ALI/ARDS的可能潜在性药物的作用和机制尚不明晰.该研究将大鼠随机分为正常组(C组)、模型组(M组)、二甲基亚砜(D组)和姜黄素治疗组(T组),通过大鼠ALI/ARDS模型,利用光镜H.E.染色观察肺部组织形态学变化,比较肺湿/干重(W/D),酶联免疫吸附法(ELISA)测定支气管肺泡灌洗液(bronchoalveolarlavage fluid,BALF)中肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和白细胞介素-6(interleukin-6,IL-6)含量动态变化,以及间接免疫荧光染色和免疫印记(Western blot)检测肺组织NF-κB蛋白水平变化,分析姜黄素对ALI的保护作用以及NF-κB、TNF-α和IL-6水平的影响.研究发现造模后4 h,M组BALF中TNF-α、IL-6升高并达高峰(P<0.05);姜黄素干预后,T组肺组织病理学改变减轻,BALF中蛋白渗出、TNF-α和IL-6明显减少(P<0.05).间接免疫荧光检测和Western blot结果显示C组大鼠肺组织蛋白抽提物中存在少量NF-κB蛋白,而M组明显升高,在4 h时达高峰,这一峰值出现时间与造模后肺内炎性损伤因子TNF-α、IL-6释放的高峰时间相吻合.姜黄素治疗后T组肺组织提取物NF-κB水平显著低于M组,且在12 h达高峰(P<0.05).D组与M组各检测指标未见差异(P>0.05).结果表明姜黄素能明显抑制ALI/ARDS后的NF-κB的表达,抑制炎性反应,对ARDS可能具有潜在治疗价值.     

NF-κ B激活在兔急性心肌梗死再灌注后无复流中的意义

目的：观察心肌核因子-κB（NF-κB）在急性心肌梗死（AMI）再灌注后无复流的活化情况,探讨NF-κB促进无复流发生发展的作用机制。方法：24只新西兰大白兔随机分为假手术组（冠状动脉只穿线不结扎）和缺血再灌注组（结扎冠状动脉2小时,再灌注1小时）,每组12只。采用凝胶阻滞迁移分析方法（EMSA）检测正常区、缺血区和无复流区心肌组织中NF-κB活性;ELISA法测定不同时点血浆中白细胞介素-6（IL-6）、超敏C反应蛋白（CRP）以及肿瘤坏死因子-α（TNF-α）的含量;光镜、电镜观察心肌组织病理变化。结果：（1）与正常区相比,缺血区和无复流区心肌组织中NF-κB活性异常升高（P〈0.01）。（2）与结扎前相比结扎后2h、再灌注后1h血浆IL-6、CRP、TNF-α水平呈进行性升高（P均〈0.05）。（3）NF-κB的活性与无复流面积、血浆IL-6、CRP以及TNF-α水平呈正相关（分别为r=0.844,P〈0.01;r=0.682,P〈0.05;r=0.687,P〈0.05;r=0.893,P〈0.01）。（4）无复流面积与血浆IL-6、CRP以及TNF-α水平呈正相关（分别为r=0.861,P〈0.01;r=0.806,P〈0.01;r=0.877,P〈0.01）。（5）光镜及电镜结果显示无复流区的心肌组织损伤较缺血区更为严重。结论：急性心肌梗死再灌注后无复流现象的发生可能与局部心肌组织中NF-κB的过度活化有关,活化的NF-κB通过促进IL-6、TNF-α等炎症因子的表达,参与无复流的发生发展过程。     

PRMT6过表达在NF-κB/p65介导小鼠肺气肿炎症反应中的作用

[目的]观察蛋白精氨酸甲基转移酶6(PRMT6)过表达在NF-κB/p65介导小鼠肺气肿模型炎症反应中的作用及机制。[方法]80只Balb/c小鼠暴露于香烟烟雾建立肺气肿模型,随机分为阴性对照组、模型组、阳性对照组(空白慢病毒载体气管内滴注)和PRMT6过表达组(PRMT6慢病毒载体气管内滴注)各20只。HE法观察肺组织形态学,Western Blot测定肺组织PRMT6表达。ELISA测定肺泡灌洗液(BALF)和肺组织匀浆中肿瘤坏死因子-α(TNF-α)和白细胞介素-8(IL-8)水平。[结果]与阴性对照组比较,模型组和阳性对照组小鼠气道阻力、BALF和肺组织匀浆TNF-α及IL-8水平、肺组织NF-κB/p65表达均升高,动态肺顺应性、肺组织PRMT6相对表达量降低(P<0.05);与模型组和阳性对照组比较,PRMT6过表达组小鼠气道阻力、BALF和肺组织匀浆TNF-α及IL-8水平、肺组织NF-κB/p65表达降低,动态肺顺应性、肺组织PRMT6相对表达水平升高(P<0.05)。[结论]PRMT6过表达可能通过抑制肺气肿小鼠肺组织NF-κB/p65核转位,发挥抗炎作用,改善肺功能。     

芹菜素对缺血再灌注大鼠心肌核转录因子-κB和ICAM-1表达的影响

目的研究芹菜素对缺血再灌注大鼠心肌核转录因子-κB(NF-κB)和粘附分子ICAM-1表达的影响,探讨其抗心肌缺血再灌注损伤的可能机制。方法将Wistar大鼠随机分为6组:假手术组、缺血再灌注组(IR组)、溶剂对照组、维拉帕米阳性对照组、芹菜素低、高剂量用药组。采用结扎左冠状动脉前降支制作缺血再灌注模型,心肌缺血30 min,再灌注2 h。免疫组化染色检测心肌组织的NF-κB和ICAM-1的表达.结果芹菜素组可降低心肌组织NF-κB和ICAM-1的表达,与IR组比较有显著差异(P0.05)。结论芹菜素对缺血再灌注心肌的保护作用可能与其减少心肌缺血再灌注后NF-κB和ICAM-的激活有关。     

Mitigation of chlorine gas lung injury in rats by postexposure administration of sodium nitrite

Nitrite (NO(2)(-)) has been shown to limit injury to the heart, liver, and kidneys in various models of ischemia-reperfusion injury. Potential protective effects of systemic NO(2)(-) in limiting lung injury or enhancing repair have not been documented. We assessed the efficacy and mechanisms by which postexposure intraperitoneal injections of NO(2)(-) mitigate chlorine (Cl(2))-induced lung injury in rats. Rats were exposed to Cl(2) (400 ppm) for 30 min and returned to room air. NO(2)(-) (1 mg/kg) or saline was administered intraperitoneally at 10 min and 2, 4, and 6 h after exposure. Rats were killed at 6 or 24 h. Injury to airway and alveolar epithelia was assessed by quantitative morphology, protein concentrations, number of cells in bronchoalveolar lavage (BAL), and wet-to-dry lung weight ratio. Lipid peroxidation was assessed by measurement of lung F(2)-isoprostanes. Rats developed severe, but transient, hypoxemia. A significant increase of protein concentration, neutrophil numbers, airway epithelia in the BAL, and lung wet-to-dry weight ratio was evident at 6 h after Cl(2) exposure. Quantitative morphology revealed extensive lung injury in the upper airways. Airway epithelial cells stained positive for terminal deoxynucleotidyl-mediated dUTP nick end labeling (TUNEL), but not caspase-3. Administration of NO(2)(-) resulted in lower BAL protein levels, significant reduction in the intensity of the TUNEL-positive cells, and normal lung wet-to-dry weight ratios. F(2)-isoprostane levels increased at 6 and 24 h after Cl(2) exposure in NO(2)(-)- and saline-injected rats. This is the first demonstration that systemic NO(2)(-) administration mitigates airway and epithelial injury.     

Interleukin-1beta augments in vitro alveolar epithelial repair

Biologically active interleukin (IL)-1beta is present in the pulmonary edema fluid obtained from patients with acute lung injury and has been implicated as an important early mediator of nonpulmonary epithelial wound repair. Therefore, we tested the hypothesis that IL-1beta would enhance wound repair in cultured monolayers from rat alveolar epithelial type II cells. IL-1beta (20 ng/ml) increased the rate of in vitro alveolar epithelial repair by 118 +/- 11% compared with that in serum-free medium control cells (P < 0.01). IL-1beta induced cell spreading and migration at the edge of the wound but not proliferation. Neutralizing antibodies to epidermal growth factor (EGF) and transforming growth factor-alpha or inhibition of the EGF receptor by tyrphostin AG-1478 or genistein inhibited IL-1beta-induced alveolar epithelial repair, indicating that IL-1beta enhances in vitro alveolar epithelial repair by an EGF- or transforming growth factor-alpha-dependent mechanism. Moreover, the mitogen-activated protein kinase pathway is involved in IL-1beta-induced alveolar epithelial repair because inhibition of extracellular signal-regulated kinase activation by PD-98059 inhibited IL-1beta-induced alveolar epithelial repair. In conclusion, IL-1beta augments in vitro alveolar epithelial repair, indicating a possible novel role for IL-1beta in the early repair process of the alveolar epithelium in acute lung injury.     

Macrolide antibiotics protect against immune complex-induced lung injury in rats: role of nitric oxide from alveolar macrophages.

Macrolide antibiotics have unique immunomodulatory actions apart from antimicrobial properties. We studied the effects of macrolides on IgG immune complex (IgG-ICx)-induced lung injury in rats in vivo and in vitro. Intrapulmonary deposition of IgG-ICx produced a time-dependent increase in the concentration of NO in exhaled air. There were corresponding increases in the number of neutrophils accumulated into alveolar spaces, and lung wet-to-dry weight ratio. All of these changes were inhibited by pretreatment with erythromycin or josamycin, but not by amoxicillin or cephaclor. Incubation of cultured pulmonary alveolar macrophages caused up-regulation of NO production and expression of inducible NO synthase mRNA, an effect that was dose dependently inhibited by erythromycin, roxithromycin, or josamycin. The macrolides also reduced IgG-ICx-induced release of IL-1beta and TNF-alpha, but did not alter the release of NO induced by exogenously added IL-1beta and TNF-alpha. These results suggest that macrolide antibiotics specifically inhibit immune complex-induced lung injury presumably by inhibiting cytokine release and the resultant down-regulation of inducible NO synthase gene expression and NO production by rat pulmonary alveolar macrophages.     

NDRG2 Is a Novel p53-Associated Regulator of Apoptosis in C6-Originated Astrocytes Exposed to Oxygen-Glucose Deprivation

N-myc downstream-regulated gene 2 (NDRG2) has been documented to be a pro-differentiative and anti-proliferative gene in cancer research. Our previous study found a significant NDRG2 up-regulation in reactive astrocytes of penumbra after transient focal cerebral ischemia, which was parallel to the enhancement of TUNEL-positive signals. However, it is still uncertain whether NDRG2 participates in cellular apoptosis induced by ischemia-reperfusion injury in brain. In this study, we investigated the role of NDRG2 in cellular apoptosis induced by oxygen-glucose deprivation (OGD) in IL-6-differentiated C6 glioma cells. The results showed that NDRG2 was up-regulated and translocated from the cytoplasm to the nucleus after OGD exposure. NDRG2 over-expression exhibited an anti-proliferative effect and increased the Bax/Bcl-2 ratio after OGD exposure, while NDRG2 silencing promoted the cellular proliferation and attenuated the up-regulation of Bax/Bcl-2 ratio. The pro-apoptotic effect of p53 was verified by the results in which p53 silencing greatly reduced the percentage of OGD-induced apoptotic cells. p53 silencing also reduced the OGD-induced NDRG2 up-regulation. However, over-expression of p53 did not further improve the NDRG2 up-regulation. In conclusion, NDRG2 is a p53-associated regulator of apoptosis in C6-originated astrocytes after OGD exposure. These findings bring insight to the roles of NDRG2 in ischemic-hypoxic injury and provide potential targets for future clinical therapies on stroke.     

Regulatory effects of eotaxin on acute lung inflammatory injury

Eotaxin, which is a major mediator for eosinophil recruitment into lung, has regulatory effects on neutrophil-dependent acute inflammatory injury triggered by intrapulmonary deposition of IgG immune complexes in rats. In this model, eotaxin mRNA and protein were up-regulated during the inflammatory response, resulting in eotaxin protein expression in alveolar macrophages and in alveolar epithelial cells. Ab-induced blockade of eotaxin in vivo caused enhanced NF-kappaB activation in lung, substantial increases in bronchoalveolar lavage levels of macrophage inflammatory protein (MIP)-2 and cytokine-induced neutrophil chemoattractant (CINC), and increased MIP-2 and CINC mRNA expression in alveolar macrophages. In contrast, TNF-alpha levels were unaffected, and IL-10 levels fell. Under these experimental conditions, lung neutrophil accumulation was significantly increased, and vascular injury, as reflected by extravascular leak of (125)I-albumin, was enhanced. Conversely, when recombinant eotaxin was administered in the same inflammatory model of lung injury, bronchoalveolar lavage levels of MIP-2 were reduced, as was neutrophil accumulation and the intensity of lung injury. In vitro stimulation of rat alveolar macrophages with IgG immune complexes greatly increased expression of mRNA and protein for MIP-2, CINC, MIP-1alpha, MIP-1beta, TNF-alpha, and IL-1beta. In the copresence of eotaxin, the increased levels of MIP-2 and CINC mRNAs were markedly diminished, whereas MIP-1alpha, MIP-1beta, TNF-alpha, and IL-1beta expression of mRNA and protein was not affected. These data suggest that endogenous eotaxin, which is expressed during the acute lung inflammatory response, plays a regulatory role in neutrophil recruitment into lung and the ensuing inflammatory damage.     

Proinflammatory response of alveolar epithelial cells is enhanced by alveolar macrophage-produced TNF-alpha during pulmonary ischemia-reperfusion injury

Pulmonary ischemia-reperfusion (IR) injury entails acute activation of alveolar macrophages followed by neutrophil sequestration. Although proinflammatory cytokines and chemokines such as TNF-alpha and monocyte chemoattractant protein-1 (MCP-1) from macrophages are known to modulate acute IR injury, the contribution of alveolar epithelial cells to IR injury and their intercellular interactions with other cell types such as alveolar macrophages and neutrophils remain unclear. In this study, we tested the hypothesis that following IR, alveolar macrophage-produced TNF-alpha further induces alveolar epithelial cells to produce key chemokines that could then contribute to subsequent lung injury through the recruitment of neutrophils. Cultured RAW264.7 macrophages and MLE-12 alveolar epithelial cells were subjected to acute hypoxia-reoxygenation (H/R) as an in vitro model of pulmonary IR. H/R (3 h/1 h) significantly induced KC, MCP-1, macrophage inflammatory protein-2 (MIP-2), RANTES, and IL-6 (but not TNF-alpha) by MLE-12 cells, whereas H/R induced TNF-alpha, MCP-1, RANTES, MIP-1alpha, and MIP-2 (but not KC) by RAW264.7 cells. These results were confirmed using primary murine alveolar macrophages and primary alveolar type II cells. Importantly, using macrophage and epithelial coculture methods, the specific production of TNF-alpha by H/R-exposed RAW264.7 cells significantly induced proinflammatory cytokine/chemokine expression (KC, MCP-1, MIP-2, RANTES, and IL-6) by MLE-12 cells. Collectively, these results demonstrate that alveolar type II cells, in conjunction with alveolar macrophage-produced TNF-alpha, contribute to the initiation of acute pulmonary IR injury via a proinflammatory cascade. The release of key chemokines, such as KC and MIP-2, by activated type II cells may thus significantly contribute to neutrophil sequestration during IR injury.     

Effects of esculetin on lipopolysaccharide (LPS)-induced acute lung injury via regulation of RhoA/Rho Kinase/NF-кB pathways in vivo and in vitro

The purpose of the present study was to investigate the protective effect of esculetin (ES) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the lung epithelial A549 cells. Mice were intragastrically administered with ES (20 and 40 mg/kg) 1 h prior to LPS challenge. ES pretreatment at doses of 20 and 40 mg/kg effectively attenuated LPS-induced lung histopathological change, myeloperoxidase or MPO activity, inflammatory cells infiltration, pulmonary wet-to-dry weight ratio, and the generation of pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in vivo and in vitro. Furthermore, we demonstrated that ES blocked the activation of NF-кB and RhoA/Rho kinase pathways in LPS-induced mice and A549 cells. The results suggested that ES exhibited protective effect on ALI and might attribute partly to the inhibition of NF-кB and RhoA/Rho kinase pathways in vivo and in vitro.     

Interleukin-1beta decreases expression of the epithelial sodium channel alpha-subunit in alveolar epithelial cells via a p38 MAPK-dependent signaling pathway

Acute lung injury (ALI) is a devastating syndrome characterized by diffuse alveolar damage, elevated airspace levels of pro-inflammatory cytokines, and flooding of the alveolar spaces with protein-rich edema fluid. Interleukin-1beta (IL-1beta) is one of the most biologically active cytokines in the distal airspaces of patients with ALI. IL-1beta has been shown to increase lung epithelial and endothelial permeability. In this study, we hypothesized that IL-1beta would decrease vectorial ion and water transport across the distal lung epithelium. Therefore, we measured the effects of IL-1beta on transepithelial current, resistance, and sodium transport in primary cultures of alveolar epithelial type II (ATII) cells. IL-1beta significantly reduced the amiloride-sensitive fraction of the transepithelial current and sodium transport across rat ATII cell monolayers. Moreover, IL-1beta decreased basal and dexamethasone-induced epithelial sodium channel alpha-subunit (alpha ENaC) mRNA levels and total and cell-surface protein expression. The inhibitory effect of IL-1beta on alpha ENaC expression was mediated by the activation of p38 MAPK in both rat and human ATII cells and was independent of the activation of alpha v beta6 integrin and transforming growth factor-beta. These results indicate that IL-1beta may contribute to alveolar edema in ALI by reducing distal lung epithelial sodium absorption. This reduction in ion and water transport across the lung epithelium is in large part due to a decrease in alpha ENaC expression through p38 MAPK-dependent inhibition of alpha ENaC promoter activity and to an alteration in ENaC trafficking to the apical membrane of ATII cells.