甘氨酸抑制脂多糖介导的鼠枯否细胞激活的时相选择及机制探讨

目的探讨甘氨酸抑制脂多糖介导的鼠枯否细胞激活效应相关机制和甘氨酸的最佳用药时机。方法将40只BALB/c小鼠分为内毒素组、预防组、早期治疗组和后期治疗组,每组10只。分离培养枯否细胞后,内毒素组加入脂多糖(10mg/L),预防组、早期治疗组和后期治疗组分别在加入脂多糖前24h、加入后0和4h加入甘氨酸(1mmol/L),分别在加入脂多糖后0、1、2、6和12h,采用逆转录聚合酶链反应及蛋白印迹法测定枯否细胞的白细胞介素1受体相关激酶4(IRAK4)mRNA和蛋白表达水平,用酶联免疫吸附法检测枯否细胞的核因子κB(NFκB)活性和培养上清液的肿瘤坏死因子α(TNFα)含量。结果脂多糖刺激后,预防组的IRAK4mRNA和蛋白表达、NFκB活性的相对峰值分别为3.64±1.13、34.54±10.31、0.47±0.10,TNFα峰值为(1780.70±210.17)pg/ml,与早期治疗组比较,差异均无统计学意义,但与内毒素组和后期治疗组比较,各峰值均明显降低,差异有统计学意义。结论提前或者在脂多糖刺激的同时应用甘氨酸,能有效抑制脂多糖介导的枯否细胞激活效应,其作用机制之一可能为抑制IRAK4的表达。     

Ketamine suppresses endotoxin-induced NF-kappaB activation and cytokines production in the intestine

BACKGROUND: Ketamine has been advocated for anesthesia in endotoxemic and other severely ill patients because it is a cardiovascular stimulant. However, ketamine also suppresses serum levels of endotoxin-induced tumor necrosis factor-alpha, and reduces mortality in mice in endotoxin shock. Our study was designed to investigate the protective effect of ketamine on the endotoxin-induced proinflammatory cytokines and nuclear factor kappa B (NF-kappaB) activation in vivo. METHODS: Adult male Wistar rats were randomly divided into six groups: saline controls; rats challenged with endotoxin (5 mg kg(-1)) and treated with saline; challenged with endotoxin (5 mg kg(-1)) and treated with ketamine (0.5 mg kg(-1)); challenged with endotoxin (5 mg kg(-1)) and treated with ketamine (5 mg kg(-1)); challenged with endotoxin (5 mg kg(-1)) and treated with ketamine (50 mg kg(-1)); and saline injected and treated with ketamine (50 mg kg(-1)). TNF-alpha, IL-6 and NF-kappaB were investigated in the tissues of the intestine (jejunum) after 1, 4 and 6 h. RESULTS: Endotoxin caused transient production of TNF-alpha and IL-6 and activation of NF-kappaB in the intestine at peak times of 1, 4 and 1 h, respectively. Ketamine 0.5 mg kg(-1) suppressed endotoxin-induced TNF-alpha elevation and inhibited NF-kappaB activation in the intestine; a dose of 5 mg kg(-1) was required to inhibit IL-6. CONCLUSION: Ketamine suppresses the production of proinflammatory cytokines such as TNF-alpha and IL-6 in the intestine, possibly via inhibition of NF-kappaB.     

Endotoxin tolerance attenuates liver ischemia/reperfusion injury by down-regulation of interleukin-1 receptor-associated kinase 4 in kupffer cells

Aim

The aim of this study was to study the role of interleukin-1 receptor-associated kinase 4 (IRAK-4) in the formation of endotoxin tolerance (ET) in liver ischemia/reperfusion (I/R) injury.

Methods

Animals were randomly divided into 3 groups: control group, I/R group, and ET group. Liver morphological changes were observed using optical microscopy with hematoxylin eosin (HE) staining. Alanine aminotransferase (ALT) was quantified to measure liver functional injury. The messenger RNA (mRNA) and protein expressions of IRAK-4 in Kupffer cells (KCs) isolated from recipients were detected using real-time polymerase chain reaction (PCR) and Western blot, respectively. The activities of NF-κB and the supernatant levels of tumor necrosis factor-alpha (TNF-α), IL-10 were assayed using enzyme-linked immunosorbent assay (ELISA).

Results

Endotoxin preconditioning improved hepatic tissue injury as indicated by morphological analysis, whereas serum ALT levels were significantly decreased at various times (P < .05); concurrently, the expression of IRAK-4 and TNF-α in KCs was down-regulated (P < .05) and the secretion of IL-10 was enhanced (P < .05); NF-κB DNA-binding activity of KCs was also significantly inhibited by endotoxin preconditioning (P < .05).

Conclusion

Endotoxin preconditioning attenuated the liver I/R injury caused by transplantation. The expression of IRAK-4 in KCs may play an important role in the formation of ET.     

p38 mitogen-activated protein kinase-dependent chemokine production, leukocyte recruitment, and hepatocellular apoptosis in endotoxemic liver injury

OBJECTIVE: To determine the role of p38 mitogen-activated protein kinase (MAPK) signaling in endotoxin-induced liver injury. BACKGROUND: MAPKs have been reported to play a potential role in regulating inflammatory responses, but the role of p38 MAPK signaling in chemokine production, leukocyte recruitment, and hepatocellular apoptosis in the liver of endotoxemic mice is not known. METHODS: Endotoxin-induced leukocyte-endothelium interactions were studied by use of intravital fluorescence microscopy in the mouse liver. Tumor necrosis factor-alpha (TNF-alpha) and CXC chemokines, liver enzymes, and apoptosis were determined 6 hours after endotoxin challenge. The specific p38 MAPK inhibitor SB 239063 was given immediately prior to endotoxin exposure. Phosphorylation and activity of p38 MAPK were determined by immunoprecipitation and Western blot. RESULTS: Endotoxin increased phosphorylation and activity of p38 MAPK in the liver, which was markedly inhibited by SB 239063. Inhibition of p38 MAPK signaling dose-dependently decreased endotoxin-induced leukocyte rolling, adhesion, and sinusoidal sequestration of leukocytes. SB 239063 markedly reduced endotoxin-induced formation of TNF-alpha and CXC chemokines in the liver. Indeed, the endotoxin-provoked increase of liver enzymes and hepatocellular apoptosis were abolished and sinusoidal perfusion was restored in endotoxemic mice treated with SB 239063. CONCLUSIONS: This study demonstrates that p38 MAPK signaling plays an important role in regulating TNF-alpha and CXC chemokine production in endotoxemic liver injury and that inhibition of p38 MAPK activity abolishes endotoxin-induced leukocyte infiltration as well as hepatocellular apoptosis. These novel findings suggest that interference with the p38 MAPK pathway may constitute a therapeutic strategy against septic liver damage.     

The protective effects of early treatment with propofol on endotoxin-induced acute lung injury in rats

To investigate the effects of treatment with propofol administration at different time point in acute lung injury of endotoxin-induced shock rats. METHODS: 76 male wistar rats were randomly assigned to five groups: A) control group; B) endotoxemic group, receiving intravenous lipopolysaccharide (LPS) 8 mg.kg-1; C) pretreatment group, treated identically to endotoxemic group with the additional administration of propofol (5 mg.kg-1 bolus, followed by infusion at 10 mg.kg-1.h-1) of 1 hr prior to the injection of LPS; D) simultaneously treatment group, treated identically to endotoxemic group with the additional administration of propofol simultaneously with the injection of LPS; E) post-treatment group, which was treated identically to endotoxemic group except for administration of propofol 1 hr after the injection of LPS. PaO2, pH, MAP and survival rate were recorded and plasma NO, TNF-alpha were measured during 5-hr after the injection of LPS. After the rats were killed, lung tissue was sampled to measured expression of inducible nitric oxide synthase (iNOS), nitrotyrosine (NT), myeloperoxidase (MPO) activity, malondialdehyde (MDA), wet-to-dry lung weight ratio (W/D), and pulmonary permeability index (PPI). RESULTS: Compared with the endotoxemic group, both the pretreatment and simultaneously treatment groups, significantly improved PaO2, pH, MAP and 5th hour survival rate of rats, and attenuated endotoxin-induced increased iNOSmRNA, NT expression, MPO activity and MDA level in lung tissue, and decreased pulmonary microvascular permeability, TNF-alpha, NO in plasma. But these beneficial efficacies were blunted in the post-treatment group. CONCLUSIONS: These findings showed that propofol administration may provide protective effects on acute lung injury in endotoxin-induced shock.     

Preventive effect of preoperative portal vein ligation on endotoxin-induced hepatic failure in hepatectomized rats is associated with reduced tumour necrosis factor alpha production

BACKGROUND: Preoperative portal vein embolization successfully reduces the incidence of postoperative hepatic failure in which endotoxin is postulated to be involved. To identify the mechanism of this preventive effect, the relationship of endotoxin-induced liver injury with tumour necrosis factor (TNF) alpha and nitric oxide production in the peripheral blood, liver and spleen of rats subjected to preoperative portal vein branch ligation (PVL) was compared with that in rats undergoing sham operation. METHODS: Rats with PVL and those that underwent sham operation were subjected to resection of ligated liver lobes (PVL-Hx rats) and two-thirds hepatectomy (noPVL-Hx rats) respectively at day 5, followed by intravenous administration of endotoxin 200 microgram/kg body-weight at day 7. At various time intervals after endotoxin injection, the peripheral blood, liver and spleen tissues were harvested and analysed for TNF-alpha and nitric oxide production. RESULTS: The survival rates of noPVL-Hx and PVL-Hx rats at 48 h after endotoxin administration were 40 and 100 per cent respectively. The former rats showed more extensive liver injury as represented by higher serum aminotransferase and hyaluronate levels than the latter. Plasma concentrations of TNF-alpha at 1.5 h after endotoxin treatment were significantly higher in noPVL-Hx rats (mean(s.e.m.) 22 125(2175) pg/ml; n = 6) than PVL-Hx rats (8344(4076) pg/ml; n = 6) (P < 0.01). Consistent with this, expression of TNF-alpha messenger RNA in the liver and spleen was suppressed in PVL-Hx rats. In two-thirds hepatectomized rats, plasma TNF-alpha concentrations after endotoxin administration at 1, 2 and 3 days (14 350(2186), 26 375(2478) and 23 000(3745) pg/ml respectively; n = 6 each) were significantly higher than that before operation (9067(1559) pg/ml; n = 6) (P < 0.05), whereas those at 5 and 7 days (10 102(3616) and 8580(1427) pg/ml respectively; n = 6 each) showed no significant increase. Furthermore, nitric oxide production in peripheral blood and liver was suppressed by preoperative PVL. CONCLUSION: Prevention of endotoxin-induced liver failure by preoperative PVL is associated with reduced production of TNF-alpha in the later phase of liver regeneration.     

Role of p38 mitogen-activated protein kinase in Kupffer cell secretion of the proinflammatory cytokines after burn trauma

This study was designed to investigate the role of p38 mitogen-activated protein (MAP) kinase on Kupffer cells (KCs) secretion of proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta and hepatic injury following burn trauma. Sprague-Dawley rats were randomized into four groups: (1) sham burn rats given vehicle, (2) sham burn rats given the p38 MAP kinase inhibitor SB203580 (10mg/kg i.v., 15min and 12h after sham burn), (3) rats given a 30% total body surface area (TBSA) full-thickness burn and fluid resuscitation plus vehicle, and (4) burn rats given injury and fluid resuscitation plus SB203580. Rats from each group were killed at 24h post-burn to examine plasma aspartate transaminase (AST) and alanine transaminase (ALT) and KCs were isolated. The KCs secretion of TNF-alpha and IL-1beta and p38 MAP kinase activity (by Western blot analysis) were also examined. These studies showed by more significant activation of p38 MAP kinase in KCs harvested from burn rats than from shams. Burn trauma resulted in hepatic dysfunction and promoted KCs secretion of TNF-alpha and IL-1beta. SB203580 inhibited p38 MAP kinase activity, reduced KCs secretion of proinflammatory cytokines, and alleviated burn-mediated hepatic dysfunction. These data suggest p38 MAP kinase activation is one important aspect of the signaling event that may mediate the KCs secretion of proinflammatory cytokines TNF-alpha and IL-1beta following burn trauma.     

Kupffer细胞CD14及Toll样受体4介导大鼠肝移植缺血再灌注损伤的机制

目的研究大鼠肝移植缺血再灌注后Kupffer细胞CD14和Toll样受体4(TLR4)的表达及其参与缺血再灌注损伤的机制。方法建立肝移植缺血再灌注模型,并分为正常对照组、缺血再灌注组、抗CD14抗体组,每组均为10只大鼠。分离培养大鼠肝移植缺血再灌注后的Kupffer细胞。检测Kupffer细胞CD14及TLR4的mRNA、蛋白表达、核转录因子κB(NFκB)活性以及培养上清TNFα的分泌量。结果再灌注后Kupffer细胞CD14及TLR4的mRNA和蛋白表达明显高于正常对照组(P<001),再灌注后核转录因子κB活性、培养上清TNFα表达量明显高于对照组(P<001)。用抗CD14抗体后NFκB活性,TNFα表达量明显下降(与再灌注组相比,P<005),但仍然高于对照组(P<001)。结论缺血再灌注后肠道内毒素(脂多糖)能够上调Kupffer细胞CD14及TLR4的表达,激活NFκB,启动细胞因子的转录和分泌,但除CD14和TLR4以外的其他信号途径参与了缺血再灌注损伤。     

Effect of ibuprofen and diethylcarbamazine on the hemodynamic and inflammatory response to endotoxin in the dog

We studied the effects of pretreatment with either ibuprofen (15 mg/kg), diethylcarbamazine (DEC, 15 mg/kg), or vehicle, on the hemodynamic, hematologic, and serum tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 responses to a bolus Escherichia coli endotoxin infusion (2 mg/kg) in 21 pentobarbital-anesthetized dogs (n = 7 each group). Hematologic and cytokine data were collected before and 0.5, 1, and 3 h after endotoxin infusion. Endotoxin decreased arterial pressure (P(a)), cardiac output (CO), total leukocyte (WBC) and platelet counts, and increased lactate, TNF-alpha, and IL-6. TNF-alpha levels peaked at 1 h and decreased by 3 h, whereas IL-6 remained elevated. Ibuprofen abolished the endotoxin-induced changes in P(a) and lactate, but did not alter the initial decrease in CO, WBC, and platelets or the increase in TNF-alpha and IL-6. DEC did not alter the response to endotoxin, although the DEC group had higher TNF-alpha and IL-6 levels before endotoxin infusion compared to controls. We conclude that the cardiovascular effects of ibuprofen in the canine model of acute endotoxemia are not due to suppression of the systemic inflammatory response.     

Role of Kupffer cells in lung injury in rats administered endotoxin 1

The purpose of this study was to investigate the regulation of lung macrophages (Muvarphis) by Kupffer cells (KCs) in lung injury caused by endotoxemia. Phenotypic differences in tissue Muvarphis were also investigated. Muvarphis were isolated from gadolinium chloride (GdCl(3))- or saline-treated rats 2 h after saline or lipopolysaccharide (LPS) administration. Furthermore, rats were given GdCl(3) 24 h prior to LPS administration, and survival rate was assessed for 24 h. Moreover, lung edema was assessed 9 h after LPS injection. Expression of inflammatory mediators was measured in the liver and lung. KCs were divided into three subpopulations based on size and phagocytosis. The expression of TNF-alpha and MIP-2 was greater in the small KCs and lung Muvarphis, while the expression of IL-6, IL-10, and MCP-1 was greater in the large and intermediate KCs. GdCl(3) eliminated ED2-positive large KCs and did not have any effect on the lung Muvarphis. The number of ED1-positive KCs increased significantly in both organs after LPS challenge and was reduced by GdCl(3). The population of ED2-positive KCs did not change following LPS administration. GdCl(3) completely prevented increases in lung microvascular permeability and mortality after LPS infusion. After LPS administration, expression of TNF-alpha and IL-6 increased rapidly and then decreased gradually in both organs. GdCl(3) inhibited these increases in the liver significantly and enhanced the expression of MCP-1 and IL-10 in the lung 9 h after LPS administration. Thus, the heterogeneous response of KCs to endotoxin leads to production of certain cytokines and chemokines that affect lung function.     

内毒素血症状态下生长激素不敏感的实验研究

目的：探讨内毒素血症状态下生长激素不敏感的发生机制。方法：采用雄性SD大鼠（n=180）,静脉分别注射内毒素（LPS）、TNF-α及IL-6,部分注射LPS大鼠同时皮下注射生长激素（GH）,不同时相处死大鼠。应用RT-PCR法测定肝组织胰岛素样生长因子I(IGF I)、生长激素受体（GHR）和细胞因子信号抑制子3（COCS-3）mRNA的表达;应用RIA测定血清GH水平;应用ELISA测定血清TNF-α和IL-6水平。结果：静脉注射LPS后各时相血清GH水平无明显变化,但肝组织IGF I和GHR mRNA的表达却明显下调,最多分别达53％和89％。正常大鼠肝组织SOCS-3mRNA微弱表达,但内毒素血症鼠其表达却明显上调,最高达7.84倍。大剂量LPS注射诱导更多GHRmRNA表达下调和SOCS-3mRNA表达上调。GH可使正常鼠肝组织IGF ImRNA的表达上调25％,但与LPS同时注射则不能阻止IGF I mRNA表达的下调。LPS刺激TNF-α和IL-6的产生,且升高的IL-6水平与SOCS-2mRNA表达上调成高度正相关。静脉注射TNF-α主要使肝组织GHRmRNA表达下调,而IL-6主要使肝组织SOCS-3mRNA表达上调。结论：静脉注射LPS可以诱导生长激素的不敏感,该不敏感可能与GHRmRNA表达下调和SOCS-3mRNA表达上调有关,TNF-α和IL-6可能从不同方面介导了LPS的部分生物效应。     

Cytokines contribute to early hepatic parenchymal injury and microvascular dysfunction after bilateral hindlimb ischemia.

PURPOSE: Hepatic dysfunction may contribute to death from multiple organ dysfunction after abdominal aortic surgery. Several factors are likely responsible, and the purpose of this study was to determine whether the cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 (IL-1) are involved in initiating this remote hepatic injury. METHODS: In a normotensive rat model of 4-hour bilateral hindlimb ischemia/reperfusion (I/R), we measured systemic TNF-alpha and IL-1 levels throughout the I/R period. Rats were randomly assigned to either the 3-hour control group, the 3-hour I/R group, or the I/R group with administration of a polyclonal antibody (PAb) to TNF-alpha (I/R + TNF-alpha PAb). Direct evidence of lethal hepatocyte injury through the labeling of nuclei by propidium iodide (per 10(-1)mm(3)) and altered microvascular perfusion were assessed by using intravital microscopy. RESULTS: Systemic TNF-alpha peaked at 83.97 pg/mL (P <.05, n = 5) at 30 minutes of reperfusion and returned to baseline in 60 to 90 minutes. No significant change in systemic IL-1 was detected (P <.05, n = 4). Alanine aminotransferase increased 2.5-fold in the I/R group through 3 hours of reperfusion (P <.05, n = 4), and TNF-alpha PAb did not attenuate this alanine aminotransferase increase (P <.05, n = 6). Lethal hepatocyte injury increased by 8-fold in the I/R group compared with the control group (P <.05, n = 5), whereas TNF-alpha PAb significantly reduced this injury (P <.05, n = 4). No regional differences in injury were noted within the acinus. Total perfusion within the microvascular unit did not drop; however, significant flow heterogeneity was observed. The proportion of continuously perfused sinusoids declined in the I/R group after 3 hours of reperfusion in both periportal (62.0 +/- 2.2, P <.05) and, to a lesser, although significant, degree, in the pericentral regions (73. 2 +/- 1.73, P <.05). CONCLUSION: By scavenging extracellular TNF-alpha with a PAb, we provide direct evidence that TNF-alpha contributes to, but is not solely responsible for, early remote hepatocellular injury and microvascular dysfunction. The administration of TNF-alpha PAb reduced lethal hepatocyte injury in both regions of the acinus and also improved perfusion in the periportal region (76.8 +/- 5.41, P <.05), but not in the pericentral region. This suggests that TNF-alpha released during reperfusion mediates early remote hepatocellular injury and microvascular dysfunction after a remote ischemic insult.     

阿霉素诱导热休克蛋白72对大鼠肝脏冷缺血-再灌注损伤的保护作用

目的观察阿霉素（DXR）预处理诱导大鼠肝脏热休克反应在肝脏长时间冷缺血一再灌注损伤中对肝细胞的保护作用。方法供体大鼠术前按1mg／kg由外周静脉注射DXR（DXR组）,对照组注射生理盐水。48h后行肝脏原位冷灌注,获取肝脏后将其在4℃UW液中保存48h,然后行原位肝移植,再灌注1、3h。逆转录-聚合酶链反应法测定肝组织肿瘤坏死因子-α（TNF-α）mRNA、中性粒细胞化学趋化性细胞因子（CINC）mRNA、巨噬细胞炎症蛋白-2（MIP-2）mRNA的表达,蛋白质印迹法测定肝组织热休克蛋白72（HSP72）、核转录因子-κB（NF-κB）的表达,测定血清谷丙转氨酶、TNF-α、CINC、MIP-2水平。同时观察7d生存率。结果DXR组TNF-α mRNA、CINCmRNA、MIP-2mRNA的表达均低于对照组。DXR组HSP72表达显著,对照组基本无表达;DXR组NF-κB无表达,对照组显著表达。DXR组血清TNF-α、CINC、MIP-2显著低于对照组（P〈0．05）。DXR组7d生存率为50％,对照组为0（P〈0．05）。结论DXR预处理大鼠供肝可使肝脏长时间冷缺血-再灌注损伤显著减轻;HSP72的诱导可抑制NF-κB激活导致的炎症反应,对肝实质细胞提供保护作用。     

Sublethal endotoxin administration evokes super-resistance to systemic hypoxia in rats

BACKGROUND: Systemic hypoxia following surgical injury modulates cytokine and catecholamine responses. Endotoxin tolerance develops after pretreatment of animals with sublethal endotoxin doses and is characterized by a reduced inflammatory cytokine response to subsequent endotoxin challenges. The administration of endotoxin also attenuates ischemic injury of rat myocardial tissue following hypoxia, a phenomenon described as cross-tolerance. The objectives of this study were: 1) to determine whether endotoxin evokes a cross-tolerance to systemic hypoxia in rats; and 2) to estimate circulatory and pulmonary performance in rats with systemic hypoxia after endotoxin pretreatment. METHODS: Seventy-two hours before the experiment, Wistar rats were given an intraperitoneal injection of endotoxin at a dose of 10 microg/kg. Polyethylene catheters were inserted into the femoral vein for infusion, and into the femoral artery for blood sampling and blood pressure monitoring. Systemic hypoxia was achieved by continuous inhalation of a modified gas mixture (9% oxygen+ 91% N2) for 4 hours. Plasma TNF-alpha and IL-6 were measured by ELISA, and norepinephrine (NE) by HPLC. RESULTS: The hypoxic rats that were pretreated with saline showed a significant decrease in mean arterial blood and base excess, as compared with the normoxic rats. Endotoxin pretreatment prevented the drop in mean arterial pressure during hypoxia and reduced the decrease in base excess. Hypoxic conditions markedly stimulated TNF-alpha and IL-6 release and increased NE levels, compared to the normoxic rats. Pretreatment with endotoxin suppressed the hypoxia-induced cytokine production as well as attenuating the increase in NE levels CONCLUSIONS: In this rat hypoxia model, endotoxin pretreatment ameliorated the hypoxia-induced inflammatory response as well as suppressing the effects on arterial oxygenation, anaerobic metabolism and NE stimulation.     

核因子kB活化对烧伤血清诱导单核细胞细胞因子表达的影响

目的了解核因子(NF)κB活化对烧伤血清诱导单核细胞活化分泌细胞因子的作用,探讨烧伤血清激活单核细胞的机制。方法收集体外培养的人外周血单核细胞(PBMC),分别用正常人血清、烧伤患者血清、烧伤患者血清 吡咯烷二硫代氨基甲酸盐(PDTC)刺激后依次分为对照组、烧伤血清组、PDTC组。采用电泳迁移率分析法检测刺激前及刺激0.5、1.0、2.0、4.0h时PBMC的NF-κB活性;酶联免疫吸附测定法和原位杂交法检测刺激前及刺激1.0、2.0、4.0、6.0h时PBMC培养上清液中肿瘤坏死因子(TNF)α、白细胞介素(IL)8水平及TNF-αmRNA、IL-8mRNA的表达情况。结果血清刺激后,烧伤血清组PBMC NF-κB活性迅速升高,刺激1.0h时达峰值(30.2±3.5)×104积分灰度值,与对照组(4.4±0.8)×104积分灰度值比较差异有统计学意义(P<0.01).刺激2.0h后逐渐下降;而PDTC组NF-κB活性无明显升高,刺激1.0h时为(6.8±0.9)×104积分灰度值。烧伤血清组刺激PBMC1.0h时,TNF-αmRNA表达量和培养上清液中TNF-α水平即升高达峰值,并明显高于对照组(P<0·01);IL-8mRNA表达量和IL-8水平在刺激4.0h时达峰值,也明显高于对照组(P<0.01);而PDTC组PBMC培养上清液中TNF-α刺激1.0h时达峰值(0.52±0.06)μg/L;刺激4.0h时IL-8达峰值(239±20)ng/L,与对照组[(0.13±0.07)μg/L、<156ng/L]比较,差异有统计学意义(P<0·01).结论烧伤血清可通过活化NF-κB,启动PBMC对细胞因子的合成和释放,提示NF-κB活化在烧伤血清诱导PBMC分泌细胞因子的过程中起重要作用。     

NF-κB诱骗寡核苷酸对内毒素性肝损伤的保护作用和机制

目的探讨NF-κB诱骗寡脱氧核苷酸对大鼠内毒素性肝损伤的保护作用及其机制。方法60只SD大鼠随机分为对照组、内毒素(LPS)组、诱骗寡核苷酸(decoy ODNs)处理组。取各组大鼠肝组织检测NF-κB蛋白结合活性(EMSA),观察组织病理学改变(光镜)及肝细胞凋亡(TUNEL)。取静脉血检测AST(自动生化仪)以及TNF-α,IL-6的表达水平(ELISA)。结果与对照组相比,内毒素组NF-κB活性明显升高,诱发大量肝细胞凋亡,肝脏损伤明显;同时血清AST,TNF-α及IL-6明显升高(P0.01)。与内毒素组相比,NF-κB诱骗寡核苷酸处理组NF-κB活性受抑制(P0.01)、肝脏组织病理学改变和肝细胞凋亡明显减轻,血清中TNF-α和AST表达水平降低(P0.01),但IL-6表达与内毒素组差异无统计学意义(P0.05)。结论NF-κB诱骗策略能高效抑制NF-κB的活性,抑制其下游有害细胞因子的产生,从而减轻内毒素性肝损伤。     

休克期切痂对烫伤大鼠肝、肺组织高迁移率族蛋白B1表达及促炎/抗炎平衡的影响

目的 观察休克期切痂对烫伤大鼠组织早期和晚期炎症介质变化规律及相应器官功能的影响,探讨休克期切痂改善预后的分子机制。方法 Wistai大鼠30％Ⅲ度烫伤后随机分为24h切痂组和72h切痂组。分别检测肝、肺组织高迁移率族蛋白B1(HMGB1)、白介素-10(IL-10)及肿瘤坏死因子-α(TNF-α)的表达。结果烫伤后2d,肝、肺组织HMGB1、TNF-α mRNA表达增强,而IL-10mRNA伤后8d增强;24h切痂大鼠伤后4d肝、肺组织HMGB1和TNF-α mRNA表达下调,伤后8d其IL-10 mRNA表达恢复正常;72h切痂大鼠伤后8d肝、肺IL-10mRNA仍维持较高水平。伤后2．8d肝组织内TNF-α蛋白水平呈双峰改变,4d时减少;24h和72h切痂组肝TNF-α维持在正常范围;伤后2、4d肝TNF-α／IL-10比例升高,24h切痂可降低TNF-α／IL-10。此外,24h切痂组4、8d血浆天冬氨酸氨基转移酶和丙氨酸氨基转移酶含量及肺组织髓过氧化物酶活性显著降低。结论休克期切痂可阻断严重烫伤大鼠肝、肺组织早期和晚期炎症介质过度表达,维持促炎／抗炎介质平衡,改善多脏器功能。