腺病毒介导的激活大鼠阴茎海绵体平滑肌细胞中NO／cGMP通路的实验研究

目的：探讨靶向大鼠iNOS基因的shRNA重组腺病毒载体对大鼠阴茎海绵体平滑肌细胞iN0s基因的激活作用,为阴茎勃起功能障碍（ED）的基因治疗提供实验依据。方法：将前期构建的重组腺病毒AdS—iN—OSrshRNA-EGFP（AdU6／shiNOS）和对照病毒AdU6／shControl,分别转染大鼠阴茎海绵体平滑肌细胞,分别在不同病毒MOI（25,50,75）值下72小时后采样检测。采用realtimeRT-PCR半定量检测AdU6／shiNOS对细胞iNOS基因mRNA表达影响;Western—blot法检测海绵体平滑肌细胞iNOS蛋白表达变化。然后培养基中加L—Arg（10mmol／L）,用酶联免疫法检测病毒转染72小时后海绵体平滑肌细胞内cGMP的浓度变化,记录AdU6／shiNOS对平滑肌细胞内cGMP的影响。结果：AdU6／shiNOS转染大鼠阴茎海绵体平滑肌细胞72小时后,和空白对照组、阴性对照组相比iN0s基因在mRNA和蛋白表达水平均显著上调（P〈O．05）,呈剂量依赖性,MOI一75时RNAa效果最好。而且转染72小时后,实验组原代平滑肌细胞内cGMP水平显著高于对照组及空白组（Pd0．05）。结论：利用腺病毒介导的RNAa技术,提高海绵体平滑肌细胞iN0s基因表达获得成功,可以增加阴茎海绵体平滑肌细胞cGMP水平,激活了NO／cGMP通路,这为勃起功能障碍的基因治疗研究开辟了新的方向。     

内毒素对脓毒性ARDS肺内皮细胞通透性的直接影响

内毒素可直接或间接作用于脓毒性ARDS肺内皮细胞,导致肺内皮细胞通透性增加。LBP／sCD14在LPS－EC相互作用中起着主要的调节和增敏作用,而Toll样受体可能是介导LPS信号在内皮细胞等CD14阴性细胞内传递的必要条件;同时MAPK酪氨酸磷酸化在LPS信号转导中起重要作用。内毒素对肺内皮细胞的直接影响可致肌动蛋白解聚、内皮接合部及内皮－酶底物粘着的分离,从而导致细胞旁路开放,肺内皮细胞通透性增加。另外内毒素直接引起肺内皮细胞凋亡、损伤也是导致通性增加的原因。     

p38 MAPK在LPS诱导内皮细胞表达ICAM-1中的作用

目的 研究p38丝裂原激活蛋白激酶(MAPK)信号转导通路在脂多糖(LPS)诱导人脐静脉内皮细胞(HUVEC)表达细胞间粘附分子-1(ICAM—1)中的作用。方法 脐静脉内皮细胞培养后分为两组：(1)刺激组,设不同时相点分别用LPS刺激内皮细胞;(2)预处理组,在LPS刺激前2h,用SB203580预处理内皮细胞。观察ICAM—1蛋白和mRNA表达的变化,检测内皮细胞p38MAPK活性变化。结果 LPS刺激后,内皮细胞表面ICAM—1分子在8～36h显增加,胞浆中mRNA在2h即有显增加;LPS刺激HUVEC后15min,p38MAPK活性即有升高,30～60min达高峰。p38抑制剂SB203580可显抑制LPS的诱导作用。结论 LPS可能通过激活p38MAPK信号转导通路,调节HUVEC的ICAM—1基因和蛋白表达。     

内毒素对脓毒性ARDS肺内皮细胞通透性的直接影响

内毒素可直接或间接作用于脓毒性ARDS肺内皮细胞,导致肺内皮细胞通透性增加。LBP/sCD14在LPS-Ec相互作用中起着主要的调节和增敏作用,而Toll样受体可能是介导LPS信号在内皮细胞等CD14阴性细胞内传递的必要条件;同时MAPK酪氨酸磷酸化在LPS信号转导中起重要作用。内毒素对肺内皮细胞的直接影响可致肌动蛋白解聚、内皮接合部及内皮-酶底物粘着的分离,从而导致细胞旁路开放,肺内皮细胞通透性增加。另外内毒素直接引起肺内皮细胞凋亡、损伤也是导致通透性增加的原因。     

兴奋胆碱能抗炎通路对内毒素致心肌损害的保护作用

目的：研究兴奋胆碱能抗炎通路对内毒素引起大鼠心肌损害的保护作用。方法：① 内毒素休克模型[静注内毒素（LPS）10mg/kg]：设手术对照组、单纯LPS组、迷走神经切断（VC）＋LPS组和VC＋LPS＋迷走神经电刺激（VS）组,观察电刺激迷走神经对心肌组织炎症介质和心肌酶指标的影响。②内毒素血症模型（静注LPS5mg/kg）：设LPS＋电针非经非穴组、LPS＋电针足三里穴组、VC后注射LPS组和VC＋LPS＋电针足三里穴组,观察电针副交感神经相关穴位足三里穴对内毒素血症引起的心肌组织损伤的保护作用。各组大鼠均于注射LPS后2h处死,检测血浆肌酸磷酸激酶同工酶（CK-MB）活性和组织病理学改变,内毒素休克各组测定心肌组织肿瘤坏死因子-α（TNF-α）含量。结果：刺激迷走神经可明显降低内毒素休克大鼠心肌组织TNF-α含量;刺激迷走神经或电针足三里穴能显著降低LPS注射后2h大鼠血浆CK-MB活性,减轻心肌组织病理损害;切断迷走神经能显著减轻或消除电针足三里穴的作用,进一步升高血浆CK-MB活性,加重心肌组织损害。结论：刺激副交感神经激活胆碱能抗炎通路对内毒素血症和内毒素休克大鼠心脏具有不同程度的保护作用。     

联合应用甘氨酸和甲强龙对失血性休克大鼠肝脏枯否细胞的影响

目的探讨失血性休克大鼠肝脏枯否细胞的功能变化以及联合应用甘氨酸和甲强龙对枯否细胞的影响。方法50只大鼠随机分成假休克组（仅进行手术操作但不放血诱导休克）、休克组、甘氨酸组、甲强龙组和联合治疗组（甘氨酸＋甲强龙）,每组10只。大鼠经动脉放血,造成失血性休克,随后用自体血和生理盐水回输进行复苏。复苏后2h,行肝脏枯否细胞的分离和培养,细胞培养24h后分别用1、10、100和1000ng/ml的脂多糖（LPS）刺激,测定细胞内Ca^2＋和肿瘤坏死因子α（TNF-α）水平。结果枯否细胞内Ca^2＋在20min左右开始大幅度增高,大约27min达到高峰,同时细胞内Ca^2＋浓度增加呈现LPS剂量依赖性。联合治疗组细胞内Ca^2＋浓度和TNF-a含量明显低于休克组以及低于甘氨酸、甲强龙治疗组,差异具有统计学意义（P〈0．005）。结论联合应用甘氨酸和甲强龙比单一制剂更有效抑制失血性休克后枯否细胞内Ca^2＋升高、抑制枯否细胞的激活,抑制TNF-α的过度产生和机体炎症反应。     

内毒素诱导共培养中性粒细胞——血管内皮细胞活化的体外研究

目的　建立人外周血中性粒细胞与人脐静脉血管内皮细胞系ECV 30 4体外共培养模型 ,研究内毒素对共培养中性粒细胞 血管内皮细胞活化的作用。　方法　将ECV 30 4细胞接种培养 ,待细胞接近融合 ,加入 2× 10 6/ml即时分离纯化的人外周血中性粒细胞 ,按不同的分组加入不同浓度的内毒素 (lipopolysaccharide ,LPS) ,在倒置显微镜下观察细胞形态学的改变 ,于 4、8、12、2 4h测定细胞上清中TNFα及IL 6水平的变化。　结果　不同浓度的LPS刺激内皮细胞TNFα产生没有明显的变化 ,而 1μg/mlLPS刺激共培养中性粒细胞 -ECV 30 4 ,在 4h其TNFα水平明显上升 ,10 μg/mlLPS刺激共培养中性粒细胞 -ECV 30 4 ,其TNFα水平逐渐上升 ,8h后比较明显 (P <0 .0 5 ) ,12、2 4h仍维持较高水平 ;对于单纯内毒素刺激ECV 30 4细胞 ,随着LPS浓度的增加 ,IL 6生成明显增加。 1μg/mlLPS刺激ECV 30 4IL 6自 4h后即明显上升 ,8、12h一直维持在高水平 ,直到 2 4h才明显回落。对于共培养的中性粒细胞和血管内皮细胞 ,单纯共培养中性粒细胞 -ECV 30 4IL 6无明显变化 ,而较低浓度10 0ng/mlLPS刺激共培养中性粒细胞 -ECV 30 4IL 6与 1μg/mlLPS刺激ECV 30 4相当 ,2 4h仍维持在高水平。 1μg/ml及 10 μg/ml刺激共培养中性粒细胞 -ECV 30     

HU308对脂多糖诱导小胶质细胞分泌NO及IL-6的影响

目的研究大麻素CB2受体激动剂HU308对脂多糖（LPS）诱导小胶质细胞激活后NO及IL-6分泌的影响。方法体外培养小鼠小胶质细胞株（BV-2细胞）,分为对照组、LPS刺激组及干预组（LPS＋HU308）。通过显微镜观察各组小胶质细胞的形态学变化,CCK-8法检测各组小胶质细胞的增殖情况,Griess法检测各组NO含量,ELISA法检测各组IL-6水平。结果LPS刺激组的小胶质细胞中出现大量胞体增大,伪足粗短或消失的细胞和一些坏死细胞,细胞增殖较差,NO及IL-6表达水平显著增高。经大麻素CB2受体激动剂HU308干预后,大部分细胞胞体稍大,伪足尚明显,细胞破坏程度轻,增殖较好,炎性因子表达均明显下降。结论激动小胶质细胞表面的大麻素CB2受体,可以减轻LPS造成的小胶质细胞过度活化或损伤,抑制其炎性因子N0及IL-6的分泌,从而达到中枢神经系统炎性损伤后的神经保护作用。     

体外循环触发炎症反应的病理生理机制

体外循环诱发的全身炎症反应涉及一系列复杂的急性过程，最终导致白细胞和内皮细胞激活，使不同器官的细胞功能发生障碍。补体系统激活、内毒素血症、缺血再灌注损伤和手术创伤都是体外循环后炎症反应的诱发因素。细胞因子、内毒素、一氧化氮、粘附分子参与了这一过程，其释放和作用的发挥是由细胞内转录因子(核因子κB)介导的。     

体外循环触发炎症反应的病理生理机制

体外循环诱发的全身炎症反应涉及一系列复杂的急性过程,最终导致白细胞和内皮细胞激活,使不同器官的细胞功能发生障碍。补体系统激活、内毒素血症、缺血再灌注损伤和手术创伤都是体外循环后炎症反应的诱发因素。细胞因子、内毒素、一氧化氮、粘附分子参与了这一过程,其释放和作用的发挥是由细胞内转录因子(核因子κB)介导的。     

乳铁蛋白对神经病理性痛大鼠脊髓背角PKG活性的影响

目的 探讨乳铁蛋白对神经病理性痛大鼠脊髓背角cGMP依赖性蛋白激酶(PKG)活性的影响.方法 雄性SD大鼠32只,体重200～250 g,随机分为4组(n=8):假手术组仅分离坐骨神经,不结扎,鞘内注射生理盐水10μl+50%二甲基亚砜(DMSO)10μl;余3组采用结扎坐骨神经的方法制备大鼠神经病理性痛模型,神经病理性痛组鞘内注射生理盐水10μl+50%DMSO10μl;乳铁蛋白组鞘内注射乳铁蛋白100μg+50%DMS010μl;PKG抑制剂KT5823组鞘内注射乳铁蛋白100μg+KT582310μl.给药后180 min内每隔30 min以热刺激法测定大鼠缩爪潜伏期,随后处死大鼠取脊髓背角,采用免疫荧光法检测PKG活性,并行定量分析.结果 与神经病理性痛组和KT5823组相比,乳铁蛋白组缩爪潜伏期延长,乳铁蛋白组脊髓背角PKG活性升高(P＜0.05);神经病理性痛组与KT5823组上述指标比较差异无统计学意义(P＞0.05).结论 乳铁蛋白可通过抑制脊髓背角PKG活性减轻大鼠神经病理性痛.     

Tumor necrosis factor production by Kupffer cells requires protein kinase C activation

Tumor necrosis factor (TNF) has been proposed as a primary inflammatory mediator of septic shock. In vitro and in vivo studies indicate that endotoxin- or lipopolysaccharide (LPS)-activated macrophages are a principle source of TNF; however, membrane signal transduction and intracellular pathways by which LPS triggers TNF production in macrophages are unclear. Recent evidence indicates that specific protein phosphorylation via activation of protein kinase C (PKC) is an early, critical step in the signaling of macrophage TNF production by phorbol esters. We hypothesize that PKC activation is also required in LPS-signaled Kupffer cell (KC) TNF production. Murine KCs were obtained by liver perfusion and digestion and then stimulated with LPS (Escherichia coli O111:B4) or LPS in the presence of H-7, a selective PKC inhibitor. Conditioned media was collected at 3 hr for assay of TNF utilizing the L929 cytolysis bioassay standardized to murine-rTNF-alpha. We found that H-7 inhibited significantly LPS signaled TNF release at a concentration of 10 microM, while H-8 (a cyclic nucleotide specific inhibitor) had no effect. The effect of H-7 was dose dependent and present at varying concentrations of LPS. Down regulation of PKC activity by preincubation of KCs with phorbol myristate acetate (PMA, a direct activator of PKC) also resulted in significantly reduced TNF release after LPS stimulation. The inhibitor H-7 (10 microM) also significantly inhibited LPS signaled prostaglandin E2 release in Kupffer cells. Total and specific intracellular protein phosphorylation was determined by trichloroacetic acid precipitation and SDS-polyacrylamide gel electrophoresis after labeling stimulated Kupffer cells with 32Pi. Total protein phosphorylation was not significantly altered by LPS stimulation; however, autoradiograms from PMA- and LPS-stimulated KCs demonstrate enhanced phosphorylation of a 40-kDa protein (2.7 +/- 0.9-fold) and a 33-kDa protein (3.1 +/- 1.0-fold) which were inhibited by H-7. We conclude that activation of PKC and protein phosphorylation are required steps in the signal transduction pathway of LPS-stimulated TNF production in Kupffer cells.     

A role for ELAM-1 in the pathogenesis of MOF during septic shock.

As a model for septic shock, LPS was infused into anesthetized Cynomolgus monkeys. Hematologic and metabolic parameters proved the induced shock response. The data presented show that administration of LPS to Cynomolgus monkeys induced a generalized inflammatory status, which was characterized by systemic release of the cytokines TNF and IL-6. Further it was demonstrated, using immune-histological methods, that a generalized expression in vivo of the endothelial leukocyte adhesion molecule (ELAM)-1 was induced on endothelial cells by LPS infusion. ELAM-1 expression was most pronounced on vasculature of lung tissue and skin. As shown in serial skin biopsies, ELAM-1 expression was induced rapidly: at 2 hr after the onset of LPS infusion, reaching maximum after 4 hr. The expression of ELAM-1 is considered to be of relevance for the mechanism which underlies the stasis of PMN in the tissues during septic shock.     

Differential expression of inducible nitric oxide synthase in septic shock

During cardiopulmonary bypass (CPB), the septic patient has markedly decreased peripheral vascular resistance as a consequence of endotoxin release from microorganisms. This decrease in peripheral vascular resistance is the result of endotoxin-induced nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS). iNOS and eNOS are responsible for the synthesis of NO because of various stimuli, including the bacterial endotoxin, lipopolysaccharide (LPS). We tested the hypothesis that a differential expression of iNOS among human endothelial cells and murine macrophage is dependent upon exposure to endotoxin and various pro-inflammatory cytokines. Using a human endothelial cell line, ECV-304 and murine macrophage cell line, RAW 264.7, we quantified the expression of iNOS with specific FITC-conjugated antibodies using fluorescence activated cell sorter (FACS) and NO production with a Bioxytech nitric oxide spectrophotometric assay. This in vitro septic model utilized LPS supported with species-specific interferon-gamma, interleukin-1 beta, and tumor necrosis factor-alpha. The cell type were stimulated for 8 hours with combinations of the cytokines mentioned. The FACS data demonstrated a significant stimulus-dependent increase in iNOS expression among the macrophage groups; however, the stimulated endothelial cells showed no significant change in iNOS expression. The nitric oxide production data demonstrated significant increases in NO production among macrophage stimulated groups; whereas, endothelial stimulated groups exhibit no significant change. We conclude that NO secreted during septic shock is the result of activated macrophage, not the endothelium. The clinical relevance is that the more severe the infectious process, the lower the PVR may be during CPB because of increased NO production from activated macrophage.     

丙酮酸乙酯对脓毒症休克犬肠黏膜屏障功能的保护作用

目的探讨丙酮酸乙酯（EP）对脓毒症休克犬肠黏膜屏障功能的影响。方法健康雄性杂种犬20只，内毒素（LPS）静脉注射复制犬脓毒症休克模型，随机分为对照组（8只）和EP组（12只）。对照组只接受林格液复苏。EP组另外给予丙酮酸乙酯首剂0．05g／kg．然后按0．05g·kg^-1·h^-1持续泵入。脓毒症休克模型建立前及建立后0、8、12和24h取血测定血浆二胺氧化酶（DAO）活性和血浆D-乳酸含量，试验24h处死动物后取小肠标本，进行肠黏膜炎性损伤病理学评分。结果EP组犬的肠黏膜炎性损伤程度病理学评分为2．33±0．25，明显轻于模型组的3．39±0．38，两组比较，差异有统计学意义（P〈0．05）。两组实验犬在休克后血浆D-乳酸含量和DAO活性逐渐升高，对照组较EP组升高更为明显（P〈0．05）。结论EP能显著改善肠组织灌流及功能指标，减轻肠黏膜的病理损害，对脓毒症休克时小肠有保护作用。     

Effects of lipopolysaccharide on actin reorganization and actin pools in endothelial cells

Objective: To investigate the dose and time dependent effects of lipopolysaccharide ( LPS ) on cytoskeletal F-acitn and G-actin reorganizations by visualizing their distribution and measuring their contents in human umbilical vein endothelial cell line ECV-304. Methods: F-actin was labeled with rhodamine-phalloidin and G-actln with deoxyribonuclease I (DNase I)conjugated with fluorescein isothiocyanate ( FITC ). Contents of cytoskeletal proteins were obtained by flow cytometry. Results: F-actin was mainly distributed peripherally in endothelial ceils under normal conditions. LPS stimulation caused the formation of stress fibers and fdopodia. G-actin was normally seen in perinuclear and nuclear areas in control ECV-304 cells. Under LPS stimulation, G-actin dots appeared in the cytoplasmic region. The actin disorganization was accompanied by the time-and dose-dependent decrease in F-actin pool and increase in G-actin pool. Conclusions: LPS can induce characteisic morphological alterations of actin cytoskeleton and formation of intercellular gap in endothefial cells, accompanied by changes in F-actin and G-actin pools.     

Neutrophil CD18 expression and blockade after traumatic shock and endotoxin challenge.

OBJECTIVE: The expression of the leukocyte CD18 adhesion complex on polymorphonuclear leukocytes (PMNs) was measured, and the physiologic effects of blockade of the complex were studied after trauma and sepsis. SUMMARY BACKGROUND DATA: Margination of PMNs occurs early during inflammation and depends, in part, on expression of the CD18 adhesion complex. Blockade of this adherence complex can reduce PMN-mediated damage. This study tests the hypothesis that PMN activation after resuscitated trauma produces an occult endothelial injury that increases the vulnerability to a delayed inflammatory stimulus. METHODS: Anesthetized (fentanyl) mongrel pigs were sham injured or fluid resuscitated from soft tissue injury +35% hemorrhage. Systemic blood was collected at 24-hour intervals from awake animals. The CD18 density on circulating PMNs was determined with flow cytometry using mean channel fluorescence (MCF). The CD18 receptors were blocked with monoclonal antibodies either immediately before trauma or immediately before an endotoxin (lipopolysaccharide [LPS]) challenge that was administered to all groups 3 days after the shock episode. Bronchoscopy was performed before trauma, pre-LPS, and post-LPS, and protein content was measured in bronchoalveolar lavage (BAL). RESULTS: Mean channel fluorescence was reduced on PMNs for 48 hours in animals with trauma versus animals with sham injuries. Anti-CD18 therapy produced higher circulating PMN counts compared with nontreated sham or shock groups. The incremental rise of BAL protein after shock was prevented with anti-CD18; the increment after LPS was attenuated. Anti-CD18 was administered before trauma and reduced the fluids necessary to maintain cardiac filling pressures after LPS. CONCLUSIONS: These data suggest that PMNs are activated after resuscitation from traumatic shock and that these cells produce an endothelial injury that may increase the vulnerability to a septic challenge. The broad implication is that temporarily blocking PMN adhesiveness at the time of trauma might salvage some host tissue and reduce the incidence of septic complications in the post-trauma period.     

Lipopolysaccharide impairs endothelial nitric oxide synthesis in rat renal arteries

BACKGROUND: Impaired endothelium-dependent vasodilation may contribute to hypoperfusion and failure of abdominal organs, including the kidneys during endotoxin or septic shock. In this study, the short-term (2 h) effects of bacterial lipopolysaccharide (LPS) on endothelium-dependent vasodilation in rat renal and superior mesenteric arteries were documented. METHODS: Rat renal and mesenteric arteries were dissected and exposed in vitro to LPS for two hours. The effects of LPS on vascular reactivity were determined and compared with time-matched controls. Endothelial nitric oxide (NO) release was determined using an NO microsensor in adjacent vessel segments. RESULTS: LPS impaired maximal acetylcholine (ACh)-induced endothelium-dependent vasodilation in renal arteries (62.5 +/- 8.8% vs. 34.4 +/- 7.5% in controls and LPS-exposed arteries), but not in mesenteric arteries. LPS did not alter the sensitivity of renal arteries to exogenous NO. ACh-dependent vasodilation was abolished after blocking NO synthesis with 10-4 mol/L L-NA in control and LPS-incubated renal arteries. When compared with controls, NO release induced by ACh and the receptor-independent calcium ionophore A23187 was significantly decreased (P < 0.05) in LPS-exposed renal segments and was fully abolished in endothelium-denuded segments, indicating that LPS attenuated receptor-dependent as well as receptor-independent endothelial NO release. In contrast, ACh- and A23187-induced NO release was normal in LPS-exposed mesenteric arteries. CONCLUSIONS: These results indicate that LPS-induced selective impairment of ACh-induced endothelium-dependent relaxation in rat renal arteries is caused by decreased endothelial NO release. This may contribute to the propensity for acute renal failure during septic shock.