Endotoxic Shock Model Research Articles

Chemical Composition and Anti-inflammatory Properties of the Unsaponifiable Fraction from Awara (Astrocaryum vulgare M.) Pulp Oil in Activated J774 Macrophages and in a Mice Model of Endotoxic Shock

Awara (Astrocaryum vulgare M.) pulp oil has been shown to possess anti-inflammatory properties in vivo, and contains an unsaponifiable matter rich in bioactive compounds. This study focused on the ethanolic unsaponifiable fraction (EUF) of awara pulp oil. Its chemical composition has been characterized: carotenoid, phytosterol, and tocopherol contents represent 125.7, 152.6, and 6.8 μg/mg of EUF, respectively. We further evaluated this fraction for anti-inflammatory properties in J774 macrophages activated by lipopolysaccharide (LPS) plus interferon (IFN) γ to understand the biological effects of awara pulp oil. EUF strongly decreased nitric oxide (NO), prostaglandin E(2), tumour necrosis factor (TNF) α, and interleukin (IL) -6 and -10 production in activated J774 cells. Moreover, it inhibited expression of inducible NO synthase and cyclooxygenases-2 in vitro. The anti-inflammatory properties of EUF were also confirmed in vivo by modulation of TNFα, IL-6 and IL-10 serum concentration in an endotoxic shock model. Pre-treatment with awara oil fraction offers promise as a protective means to lower the production of excessive amounts of pro-inflammatory molecules.

The anti-inflammatory effects of ethyl acetate on Lipopolysaccharide/D-galactosamine challenged mice and Lipopolysaccharide activated RAW264.7 cells

Ethyl acetate (EA) is an ordinary organic compound in fruits, wine and cosmetics, and used as a solvent frequently. With the recent observation in our experiment, we suspected that EA could affect immune function, in particular macrophage activity. In this paper, we tested EA’s protect effect against death in Lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced endotoxic shock model in mice. And also found EA decreased the LPS-induced mRNA expression of mediators of inflammation including cyclooxygenase 2 (COX2), inducible NOS (iNOS), and tumor necrosis factor α (TNF α) in RAW264.7 cells. Consequently, EA decreased the production of, TNF α and the inflammatory agent nitric oxide (NO) in RAW264.7 cells treated with LPS. Other pro-inflammatory cytokines such as IL-1h and IL-6 were similarly decreased by EA treatment of RAW264.7 cells. The potential mechanism may associate with NF-κB activity as we shown. Taken together, these results suggest that EA has anti-inflammatory properties.

11 Effect of magnetic-photo stimulating the system of nitric oxide in arterial hypertension

Materials and Methods: The main goal of this study was to investigate the effects of endogenous nitric oxide on mitochondrial respiration and to study the effects of blue (442 nm) and green (532 nm) low-power radiation on mitochondrial respiration in experimental endotoxic shock. We used a model of experimental endotoxic shock produced by intraperitoneal injection of lipopolysaccharide B. Results: Low-power laser radiation has an appreciable effect on the rate of mitochondrial respiration in states of 3 and 4, both in normal and in endotoxic shock. The result of blue laser radiation (442 nm) was an increase of mitochondrial respiratory rate V3 in the control group by 12% at dose of 6 J/cm2. Increasing the irradiation dose lead to gradual decrease in rate V3. In the case of green laser (532 nm), statistically significant deviations from control in the rate V3 is not revealed. The greatest increase in respiratory rate in state of V3 (about 30%) was observed in LPS-treated animals at dose of 6 J/cm2 (442 nm). Oxygen consumption rate in the state of 4 irradiation at dose of 10 J/cm2 increased compared to the control all sources of radiation. In an experimental endotoxic shock rate of oxygen consumption by mitochondria V4 also increased (approximately 40%) for all sources, but this effect was more pronounced than in the control group. To evaluate the mitochondria membrane potential in experimental endotoxic shock a JC-1 fluorescent probe was applied. It was found that statistically significant difference (approx. 10%) exists in the mitochondria membrane potential of in LPS-treated and untreated rats. This phenomenon could be due to the membrane damage in endotoxic shock development. Conclusion: Study of the effect of laser radiation on mitochondrial respiration showed that in experiments using blue laser (442 nm), an increase rate V3 and V4, which can be attributed to the destruction of nitrosyl complexes of the respiratory chain. This tendency was more pronounced in an experimental endotoxic shock.

Effect of Chelerythrine Against Endotoxic Shock in Mice and Its Modulation of Inflammatory Mediators in Peritoneal Macrophages Through the Modulation of Mitogen-Activated Protein Kinase (MAPK) Pathway

A quaternary benzo [c] alkaloid chelerythrine (CHE), which is a traditional herbal prescription, has been used for the treatment of various inflammatory diseases. To gain insight into the anti-inflammatory effect and molecular mechanisms underlying the anti-inflammatory activity of CHE, we used experimentally induced mice endotoxic shock moled and lipopolysaccharide (LPS)-induced murine peritoneal macrophages to examine the anti-inflammatory function of CHE. CHE displayed significant anti-inflammatory effects in experimentally induced mice endotoxic shock model in vivo through inhibition of LPS-induced tumor necrosis factor-alpha (TNF-α) level and nitric oxide (NO) production in serum. Additionally, our data suggest that CHE treatment inhibits LPS-induced TNF-α level and NO production in LPS-induced murine peritoneal macrophages through selective inhibition of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) activation. Moreover, the effects of CHE on NO and cytokine TNF-α production can possibly be explained by the role of p38 MAPK and ERK1/2 in the regulation of inflammatory mediators expression.

Effects of laser and LED radiation on mitochondrial respiration in experimental endotoxic shock

Effects of low-level laser therapy (442 and 532 nm) and LED radiation (650 nm) on mitochondrial respiration in experimental endotoxic shock have been studied. A model of experimental endotoxic shock in rats was obtained by intraperitoneal injection of lipopolysaccharide B. It was found that low-level laser therapy and LED radiation dramatically affected the rate of mitochondrial respiration in third and fourth states both in LPS-treated animals and in control experiments. The maximal increase of the mitochondrial respiration rate (of about 40 %) in LPS-treated animals was observed when blue laser was applied at the dose of 6 J/cm(2). Measurements of inner mitochondrial membrane surface potential with fluorescence probe JC-1 in LPS-treated rats showed in approximately 10 % decrease of potential in LPS-treated animals compared to control.

Antihypotensive activity of 2-acetylamino-5,6-dihydro-4H-1,3-thiazine for an endotoxic shock model in rats

The high anti-hypotonic activity of the new NOS inhibitor 2-acetylamino-5,6-dihydro-4H-1,3-thiazine hydro-bromide was demonstrated for an endotoxic shock model in rats.

Mechanism of sophorolipid (SL) suppression of nitric oxide production in models of septic or endotoxic shock. (169.9)

Abstract Introduction: Severe sepsis often leads to endotoxic shock and is reported to account for 9% of all deaths in the United States annually. Clinical manifestations of severe sepsis and shock are believed to result from the host’s overwhelming inflammatory reaction to infection and bacterial endotoxins. There is a clear need for new therapeutic approaches and agents based on a better understanding of the physiologic pathways underlying endotoxic shock. Objective: The aim of this project is to determine the mechanism of action of sophorolipids (SL) as novel therapeutic agents to block severe sepsis and shock. We established that SL were protective in vivo when injected following the initiation of endotoxic shock and in vitro when added to macrophage cultures following the addition of LPS. Methods: Cultured macrophages (RAW 264.7) were incubated for 1-5 days with LPS (0-200 ng/ml) and SL (100 ng/ml). Accumulated nitric oxide was measured using Griess reaction. Surface expression of CD14 and TLR4 was determined using specific antibodies (Santa Cruz Biotechnology, immunohistochemistry). Results: LPS induced nitric oxide production was inhibited by 70% in the presence of SL (SL alone had no effect on nitric oxide production). Surface expression of CD14 (macrophage LPS receptor) was also inhibited by 70% in the presence of SL; expression of TLR4 was inhibited by 15%. Conclusions: SL may interfere with binding and intracellular steps in the LPS-mediated gene activation cascade.

The NAMPT inhibitor FK866 reverts the damage in spinal cord injury

BackgroundEmerging data implicate nicotinamide phosphoribosyl transferase (NAMPT) in the pathogenesis of cancer and inflammation. NAMPT inhibitors have proven beneficial in inflammatory animal models of arthritis and endotoxic shock as well as in autoimmune encephalitis. Given the role of inflammatory responses in spinal cord injury (SCI), the effect of NAMPT inhibitors was examined in this setting.MethodsWe investigated the effects of the NAMPT inhibitor FK866 in an experimental compression model of SCI.ResultsTwenty-four hr following induction of SCI, a significant functional deficit accompanied widespread edema, demyelination, neuron loss and a substantial increase in TNF-α, IL-1β, PAR, NAMPT, Bax, MPO activity, NF-κB activation, astrogliosis and microglial activation was observed. Meanwhile, the expression of neurotrophins BDNF, GDNF, NT3 and anti-apoptotic Bcl-2 decreased significantly. Treatment with FK866 (10 mg/kg), the best known and characterized NAMPT inhibitor, at 1 h and 6 h after SCI rescued motor function, preserved perilesional gray and white matter, restored anti-apoptotic and neurotrophic factors, prevented the activation of neutrophils, microglia and astrocytes and inhibited the elevation of NAMPT, PAR, TNF-α, IL-1β, Bax expression and NF-κB activity.We show for the first time that FK866, a specific inhibitor of NAMPT, administered after SCI, is capable of reducing the secondary inflammatory injury and partly reduce permanent damage. We also show that NAMPT protein levels are increased upon SCI in the perilesional area which can be corrected by administration of FK866.ConclusionsOur findings suggest that the inflammatory component associated to SCI is the primary target of these inhibitors.

The NAMPT Inhibitor FK866 Reverts The Damage In Spinal Cord Injury

Emerging data implicate nicotinamide phosphoribosyl transferase (NAMPT) in the pathogenesis of cancer and inflammation. NAMPT inhibitors have proven beneficial in inflammatory animal models of arthritis and endotoxic shock as well as in autoimmune encephalitis. Given the role of inflammatory responses in spinal cord injury (SCI), the effect of NAMPT inhibitors was examined in this setting.We investigated the effects of the NAMPT inhibitor FK866 in an experimental compression model of SCI in mice. Twenty‐four hr following SCI, a significant functional deficit accompanied widespread edema, demyelination, neuron loss and a substantial increase in cytokines, PAR, NAMPT, Bax, MPO activity, NF‐κB activation, astrogliosis and microglial activation was observed. Meanwhile, levels of neurotrophins and anti‐apoptotic Bcl‐2 significantly decreased. Treatment with FK866 (10 mg/kg), the best characterized NAMPT inhibitor, at 1h and 6h after SCI rescued motor function, preserved prelesional gray and white matter, restored anti‐apoptotic and neurotrophic factors, prevented the activation of neutrophils, microglia and astrocytes and inhibited the elevation of NAMPT, PAR, TNF‐α, IL‐1β, Bax levels and NF‐κB activity. We show for the first time that FK866, administered after SCI, is capable of reducing the secondary inflammatory injury and partly reduce permanent damage. Our findings suggest that the inflammatory component associated to SCI is the primary target of these inhibitors.

The role of tetrapyrrol photosensitizers in photoinduced variation of free radical characteristics of rat blood in endotoxic shock

The main goal of the present study was to evaluate the comparative effectiveness of tetrapyrrol photosensitizers (protoporphyrine IX and chlorine e6) in red (632.8 nm) and green (532.5) spectrum bands on rat blood free radical status, using the experimental model of endotoxic shock. Endotoxic shock was produced by intraperitoneal injection of lipopolysaccharide B. Irradiation effectiveness was estimated by leukocyte activation (measured with luminol-dependent chemiluminescence), superoxide dismutase activity of blood plasma (nitro blue tetrasolium assay) and lipid peroxidation (assay with cis-parinaric acid). It was found that laser irradiation has multidirectional effects on leukocyte activation, membrane lipid peroxidation and plasma SOD activity and all these effects were more pronounced in the case of endotoxic shock. Protoporphyrin was more effective in leukocyte activation and chlorine e6 demonstrated maximal effects on blood SOD activity.

Phenylmethimazole inhibits production of proinflammatory mediators and is protective in an experimental model of endotoxic shock*

One form of sepsis, or endotoxic shock, is a hyperactivated systemic response caused by excessive expression of proinflammatory mediators, which results from Gram-negative bacterial lipopolysaccharide-stimulated Toll-like receptor-4 signaling. This lipopolysaccharide signaling is known to consist of a MyD88-dependent nuclear factor-κB-mediated pathway that results in production of proinflammatory mediators (tumor necrosis factor-α, interleukin-6, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, inducible nitric oxide synthase, cyclooxygenase-2) and a MyD88-independent interferon regulatory factor-mediated pathway that regulates production of Type 1 interferon-inducible proteins (interferon γ-induced protein-10, monocyte chemotactic protein-1). In prior studies, phenylmethimazole markedly decreased virally induced Toll-like receptor-3 expression and signaling and significantly suppressed murine colitis in an experimental model wherein lipopolysaccharide is known to play an important role. In this study, we probed the hypothesis that phenylmethimazole inhibits lipopolysaccharide-mediated Toll-like receptor-4 signaling and is efficacious in attenuating inflammatory changes and improving survival in an in vivo murine model of endotoxic shock. Experimental animal model. University laboratory. Male C57BL/6J mice weighing 18-22 g. Phenylmethimazole (1 mg/kg) was administered intraperitoneally to mice before a lethal lipopolysaccharide challenge (25 mg/kg). RAW264.7 mouse macrophage cells were pretreated with phenylmethimazole followed by lipopolysaccharide stimulation. : Macroscopic observations revealed that phenylmethimazole was significantly protective in controlling clinical manifestations of endotoxic shock and death under conditions wherein flunixin of meglumine and prednisolone were marginally effective. A combination of enzyme-linked immunosorbent assay, Northern blot, reverse transcriptase-polymerase chain reaction, immunohistochemistry, and Western blot analyses showed that phenylmethimazole attenuated lipopolysaccharide-induced increases in production of proinflammatory cytokines (tumor necrosis factor-α, interleukin-6, interferon-γ), endothelial cell adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1), inducible nitric oxide synthase and cyclooxygenase-2, interferon regulatory factor-1, interferon-inducible proteins (interferon γ-induced protein-10, monocyte chemotactic protein-1), and signal transducer and activator of transcription-1 phosphorylation in multiple tissues in mice. Consistent with these observations, electrophoretic mobility shift assay demonstrated that phenylmethimazole inhibited in vitro lipopolysaccharide-induced nuclear factor-κB and interferon regulatory factor-1 activation in RAW 264.7 mouse macrophages. Collectively, these results provide direct evidence that phenylmethimazole diminishes lipopolysaccharide-induced MyD88-dependent as well as MyD88-independent signaling pathways and is protective in an experimental model of endotoxic shock.

Effects of hexafluoro-2-propanol on inflammatory and hemodynamic responses in a rat model of endotoxic shock

Sepsis with multiple organ failure remains a leading cause of hospital morbidity and mortality on ICUs imparting tremendous financial costs. Recently, the primary metabolite of sevoflurane, hexafluoro-2-propanol (HFIP), has been found to exert immunomodulatory properties attenuating inflammatory response to lipopolysaccharides (LPS) in vitro [1]. We investigated whether HFIP attenuates plasma and tissue inflammatory mediator expression in a rat model of endotoxic shock.

Prasugrel inhibits platelet-leukocyte interaction and reduces inflammatory markers in a model of endotoxic shock in the mouse

Prasugrel, through its active metabolite, reduces atherothrombosis and its clinical manifestations by inhibiting platelet activation and aggregation. Platelets also contribute to inflammation through interaction with different classes of leukocytes. We investigated whether the inhibitory effect of prasugrel on platelets also counteract inflammatory responses. The effect of prasugrel active metabolite, R-138727, was investigated on platelet P-selectin expression, platelet adhesion to polymorphonuclear leukocytes (PMN) and monocytes (MN) and Mac-1 expression in PMN and MN, in vitro, in human cells. The ex vivo effect of prasugrel administration on P-selectin, thromboxane (TXB)2 formation, platelet-PMN conjugates and Mac-1 expression in PMN triggered by PAR-4 agonist peptide was examined in whole blood from healthy mice as well as from mice in which an acute inflammatory reaction was induced by treatment with endotoxin. The effect of prasugrel on inflammatory markers in endotoxin-treated animals was also tested in vivo. R-138727 inhibited agonist-stimulated expression of platelet P-selectin, platelet-PMN and platelet-MN adhesion and platelet-dependent Mac-1 expression in leukocytes. Addition of aspirin did not modify the inhibitory effect elicited by R-138727. Treatment of mice with prasugrel resulted in a profound inhibition of platelet P-selectin expression, TXB2 production, platelet-PMN adhesion and Mac-1 expression in PMN induced by ex vivo stimulation with PAR-4 agonist peptide of whole blood from healthy or endotoxin-treated mice. Measurement of markers revealed that prasugrel reduced TXB2 and tumour necrosis factor-α synthesis and increased nitric oxide metabolites in endotoxin-treated mice in vivo. In conclusion, prasugrel reduces platelet interactions with PMN and MN. Through these effects prasugrel may curb platelet-mediated inflammatory responses.

Labdanolic acid methyl ester (LAME) exerts anti-inflammatory effects through inhibition of TAK-1 activation

Labdane derivatives obtained from the diterpenoid labdanediol suppressed NO and PGE 2 production in LPS-stimulated RAW 264.7 macrophages. However, mechanisms involved in these inhibitory effects are not elucidated. In this study, we investigated the signaling pathways involved in the anti-inflammatory effects of labdanolic acid methyl ester (LAME) in peritoneal macrophages and examined its therapeutic effect in a mouse endotoxic shock model. LAME reduced the production of NO and PGE 2 in LPS-activated macrophages. This effect involved the inhibition of NOS-2 and COX-2 gene expression, acting at the transcription level. Examination of the effects of the diterpene on NF-κB signaling showed that LAME inhibits the phosphorylation of IκBα and IκBβ, preventing their degradation and the nuclear translocation of the NF-κB p65 subunit. Moreover, inhibition of MAPK signaling was also observed. A further experiment revealed that LAME inhibited the phosphorylation of transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1), an upstream signaling molecule required for IKK and mitogen-activated protein kinases (MAPKs) activation. Inflammatory cytokines such as IL-6, TNF-α and IP-10 were downregulated in the presence of this compound after stimulation with LPS. Additionally, LAME also improved survival in a mouse model of endotoxemia and reduced the circulatory levels of cytokines (IL-6, TNF-α). In conclusion, these results indicate that labdane diterpene LAME significantly attenuates the pro-inflammatory response induced by LPS both in vivo and in vitro.

Awara ( Astrocaryum vulgare M.) pulp oil: Chemical characterization, and anti-inflammatory properties in a mice model of endotoxic shock and a rat model of pulmonary inflammation

Awara ( Astrocaryum vulgare M.) is a palm fruit mainly used in nutrition. We analysed the pulp oil for fatty acid, tocopherol, carotenoid, and phytosterol and we evaluated whether this oil may attenuate inflammation in vivo. In an endotoxic shock model, awara pulp oil treatment decreased pro-inflammatory cytokines and increased anti-inflammatory cytokines. In a pulmonary inflammation model, awara pulp oil treatment reduced eosinophil and lymphocyte numbers recovered into the broncho-alveolar lavages. These results suggest that awara pulp oil administration can efficiently counteract an acute and chronic inflammatory response in vivo that is probably mediated by fatty acids and minor compounds.

The Hydroxylase Inhibitor Dimethyloxallyl Glycine Attenuates Endotoxic Shock Via Alternative Activation of Macrophages and IL-10 Production by B1 Cells

Localized tissue hypoxia is a feature of infection and inflammation, resulting in the upregulation of the transcription factors hypoxia-inducible factor 1α and nuclear factor κB (NF-κB) via inhibition of oxygen sensing hydroxylase enzymes. Previous studies have demonstrated a beneficial role for the hydroxylase inhibitor dimethyloxallyl glycine (DMOG) in inflammatory conditions, including experimental colitis, by regulating the activity of hypoxia-inducible factor 1 and NF-κB. We have demonstrated in vivo that pretreatment with DMOG attenuates systemic LPS-induced activation of the NF-κB pathway. Furthermore, mice treated with DMOG had significantly increased survival in LPS-induced shock. Conversely, in models of polymicrobial sepsis, DMOG exacerbates disease severity. Dimethyloxallyl glycine treatment of mice promotes M2 polarization in macrophages within the peritoneal cavity, resulting in the downregulation of proinflammatory cytokines such as TNF-α. In addition, in vivo DMOG treatment upregulates IL-10 expression, specifically in the peritoneal B1 cell population. This study demonstrates cell type-specific roles for hydroxylase inhibition in vivo and provides insight into the mechanism underlying the protection conveyed by DMOG in models of endotoxic shock.

A novel DDAH-1 inhibitor improved sepsis-induced impairment in vasoreactivity to noradrenaline in a rat endotoxaemia model

In septic shock, iNOS activation and nitric oxide (NO) overproduction contribute to vascular hyporeactivity to adrenergic vasopressors. The consequent hypotension often necessitates high doses of catecholamine administration. However, this may lead to detrimental effects on tissue perfusion, immune function and myocardial function. Asymmetric dimethlyarginine (ADMA), an endogenous inhibitor of NO synthase, is extensively metabolised by dimethylarginine dimethylaminohydrolase (DDAH). Competitive inhibition of the DDAH-1 isoform should thus reverse hypotension but, as this isoform is absent in immune cells, it should not compromise the immune effects of NO. Hence, we investigated whether L257, a novel DDAH-1 inhibitor, could spare norepinephrine dosing in a rat endotoxic shock model.

Protective effects of tryptophan on neuro-inflammation in rats after administering lipopolysaccharide

Tryptophan (TRP), which plays an important role in immune system regulation, protein synthesis, serotonin (5-HT) and melatonin production, is a potent endogenous free radical scavenger and antioxidant. The aim of this work was to determine the efficacy of TRP in neuro-inflammation induced by systemic administration of lipopolysacharide (LPS, 20mg/kg) which promotes the synthesis of free radical (LPO: MDA and 4-HDA), and pro-inflammatory cytokine Interferon-γ (IFN-γ) in different brain regions (cerebral cortex and hippocampus) of rats. Experiments were performed on adult female, pregnant and lactating rats fed with a diet of TRP content (0.5mg/100g protein), cerebral cortex and hippocampus were evaluated for lipid peroxidation (LPO) products, nitrites, nitrates and plasmatic concentration of IFN-γ. LPO levels in LPS+TRP groups were significantly decreased than that obtained in the LPS group. However, there were no observed differences in plasmatic levels of nitrites and nitrates as well as IFN-γ, neither in the cerebral cortex or hippocampus. The TRP has protective effect in the oxidative damage in a model of endotoxic shock in the breading nurslings induced by the systemic administration of LPS, acting as a scavenger of free radicals. So, it can be proposed as an innocuous protector agent in the endotoxic shock process.

Anti-Inflammatory Effects of C-Peptide Prevent Endothelial Dysfunction in Type 1 Diabetes

C-peptide, historically considered a biologically inactive peptide, has been shown to exert insulin-independent biological effects on a number of cells proving itself as a bioactive peptide with anti-inflammatory properties. Type 1 diabetes (T1D) patients typically lack physiological levels of insulin and C-peptide. Recombinant insulin administrations, in the absence of C-peptide, correct hyperglycemia but leave an increased risk of developing microvascular complications affecting the small vessels of the eye, the kidneys, and the peripheral nerves. Inflammation is an important factor for the development of diabetes-associated vascular complications, and there is increasing evidence that T1D patients, even at a young age and after short duration of T1D, have circulating activated monocytes and increased plasma levels of inflammatory cytokines. It has been hypothesized that reduced plasma levels or lack of circulating C-peptide might contribute to the development of diabetes-associated vascular complications since C-peptide is able to reduce the inflammatory response associated with T1D. In this review, we present the most-up-to date information on the anti-inflammatory activity of C-peptide at the level of the vascular endothelium exposed to a variety of glucose levels. The anti-inflammatory properties of C-peptide in animal models of endotoxic shock and T1D-associated encephalopathy are also presented. The present evidence favours the view that T1D should be considered a dual-hormone deficiency disorder and emphasizes the possibility that replacement therapy with both insulin and C-peptide in T1D patients may offer an approach to retard or completely prevent the development of diabetes-associated microvascular complications, for which no causal therapy is available today. Keywords: C-peptide, complications, diabetes, endothelium, inflammation, vascular

Isoforskolin pretreatment attenuates lipopolysaccharide-induced acute lung injury in animal models

Isoforskolin was isolated from Coleus forskohlii native to Yunnan in China. We hypothesize that isoforskolin pretreatment attenuates acute lung injury induced by lipopolysaccharide (endotoxin). Three acute lung injury models were used: situ perfused rat lung, rat and mouse models of endotoxic shock. Additionally, lipopolysaccharide stimulated proinflammatory cytokine production was evaluated in human mononuclear leukocyte. In situ perfused rat lungs, pre-perfusion with isoforskolin (100, and 200 μM) and dexamethasone (65 μM, positive control) inhibited lipopolysaccharide (10 mg/L) induced increases in lung neutrophil adhesion rate, myeloperoxidase activity, lung weight Wet/Dry ratio, permeability-surface area product value, and tumor necrosis factor (TNF)-α levels. In rats, pretreatments with isoforskolin (5, 10, and 20 mg/kg, i.p.) and dexamethasone (5 mg/kg, i.p.) markedly reduced lipopolysaccharide (6 mg/kg i.v.) induced increases of karyocyte, neutrophil counts and protein content in bronchoalveolar lavage fluid, and plasma myeloperoxidase activity. Lung histopathology showed that morphologic changes induced by lipopolysaccharide were less pronounced in the isoforskolin and dexamethasone pretreated rats. In mice, 5 mg/kg isoforskolin and dexamethasone caused 100% and 80% survival, respectively, after administration of lipopolysaccharide (62.5 mg/kg, i.v., 40% survival if untreated). In human mononuclear leukocyte, isoforskolin (50, 100, and 200 μM) and dexamethasone (10 μM) pre-incubation lowered lipopolysaccharide (2 μg/mL) induced secretion of the cytokine TNF-α, and interleukins (IL)-1β, IL-6, and IL-8. In conclusion, pretreatment with isoforskolin attenuates lipopolysaccharide-induced acute lung injury in several models, and it is involved in down-regulation of inflammatory responses and proinflammatory cytokines TNF-α, IL-1β, IL-6, and IL-8.