Cytokine-induced Neutrophil Chemoattractant Concentrations Research Articles

Comparison of pulmonary inflammatory responses following intratracheal instillation and inhalation of nanoparticles

In order to examine whether intratracheal instillation studies can be useful for determining the harmful effect of nanoparticles, we performed inhalation and intratracheal instillation studies using samples of the same nanoparticles. Nickel oxide nanoparticles (NiO) and titanium dioxide nanoparticles (TiO2) were used as chemicals with high and low toxicities, respectively. In the intratracheal instillation study, rats were exposed to 0.2 or 1 mg of NiO or TiO2. Cell analysis and chemokines in bronchoalveolar lavage fluid (BALF) were analyzed from 3 days to 6 months following the single intratracheal instillation. In the inhalation study, rats were exposed to inhaled NiO or TiO2 (1.65, 1.84 mg/m3, respectively) for 4 weeks. The same endpoints were examined from 3 days to 3 months after the end of exposure. Inhalation of NiO induced an increase in the number of neutrophils in BALF and concentrations of cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2 and heme oxygenase (HO)-1. Intratracheal instillation of NiO induced persistent inflammation and upregulation of these cytokines was observed in the rats. However, inhalation of TiO2 did not induce pulmonary inflammation, and intratracheal instillation of TiO2 transiently induced an increase in the number of neutrophils in BALF and the concentrations of CINC-1, CINC-2 and HO-1. Taken together, a difference in pulmonary inflammation was observed between the high and low toxicity nanomaterials in the intratracheal instillation studies, as in the inhalation studies, suggesting that intratracheal instillation studies may be useful for ranking the harmful effects of nanoparticles.

Pulmonary toxicity of well-dispersed cerium oxide nanoparticles following intratracheal instillation and inhalation.

We performed inhalation and intratracheal instillation studies of cerium dioxide (CeO2) nanoparticles in order to investigate their pulmonary toxicity, and observed pulmonary inflammation not only in the acute and but also in the chronic phases. In the intratracheal instillation study, F344 rats were exposed to 0.2 mg or 1 mg of CeO2 nanoparticles. Cell analysis and chemokines in bronchoalveolar lavage fluid (BALF) were analyzed from 3 days to 6 months following the instillation. In the inhalation study, rats were exposed to the maximum concentration of inhaled CeO2 nanoparticles (2, 10 mg/m3, respectively) for 4 weeks (6 h/day, 5 days/week). The same endpoints as in the intratracheal instillation study were examined from 3 days to 3 months after the end of the exposure. The intratracheal instillation of CeO2 nanoparticles caused a persistent increase in the total and neutrophil number in BALF and in the concentration of cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2, chemokine for neutrophil, and heme oxygenase-1 (HO-1), an oxidative stress marker, in BALF during the observation time. The inhalation of CeO2 nanoparticles also induced a persistent influx of neutrophils and expression of CINC-1, CINC-2, and HO-1 in BALF. Pathological features revealed that inflammatory cells, including macrophages and neutrophils, invaded the alveolar space in both studies. Taken together, the CeO2 nanoparticles induced not only acute but also chronic inflammation in the lung, suggesting that CeO2 nanoparticles have a pulmonary toxicity that can lead to irreversible lesions.

Valproic acid attenuates acute lung injury induced by ischemia-reperfusion in rats.

Evidence reveals that histone deacetylase (HDAC) inhibition has potential for the treatment of inflammatory diseases. The protective effect of HDAC inhibition involves multiple mechanisms. Heme oxygenase-1 (HO-1) is protective in lung injury as a key regulator of antioxidant response. The authors examined whether HDAC inhibition provided protection against ischemia-reperfusion (I/R) lung injury in rats by up-regulating HO-1 activity. Acute lung injury was induced by producing 40 min of ischemia followed by 60 min of reperfusion in isolated perfused rat lungs. The rats were randomly allotted to control group, I/R group, or I/R + valproic acid (VPA) group with or without an HO-1 activity inhibitor (zinc protoporphyrin IX) (n = 6 per group). I/R caused significant increases in the lung edema, pulmonary arterial pressure, lung injury scores, tumor necrosis factor-α, and cytokine-induced neutrophil chemoattractant-1 concentrations in bronchoalveolar lavage fluid. Malondialdehyde levels, carbonyl contents, and myeloperoxidase-positive cells in lung tissue were also significantly increased. I/R stimulated the degradation of inhibitor of nuclear factor-κB-α, nuclear translocation of nuclear factor-κB, and up-regulation of HO-1 activity. Furthermore, I/R decreased B-cell lymphoma-2, heat shock protein 70, acetylated histone H3 protein expression, and increased the caspase-3 activity in the rat lungs. In contrast, VPA treatment significantly attenuated all the parameters of lung injury, oxidative stress, apoptosis, and inflammation. In addition, VPA treatment also enhanced HO-1 activity. Treatment with zinc protoporphyrin IX blocked the protective effect of VPA. VPA protected against I/R-induced lung injury. The protective mechanism may be partly due to enhanced HO-1 activity following HDAC inhibition.

Protection against reperfusion lung injury via aborgating multiple signaling cascades by trichostatin A.

Trichostatin A (TSA) is a histone deacetylase inhibitor with anti-inflammatory effects. Nonetheless, little information is available about the effect of TSA in ischemia-reperfusion (IR)-induced lung injury. In a perfused rat lung model, IR was induced by 40min of ischemia followed by 60min of reperfusion. The rat lungs were randomly divided into several groups including control, control+TSA (0.1mg/kg), IR, and IR+various dosages of TSA (0.05, 0.075, 0.1mg/kg). Bronchoalveolar lavage fluids and lung tissues were obtained and examined at the end of the experiment. TSA dose-dependently diminished IR-induced increased vascular permeability and edema, pulmonary artery pressure, and histological changes in the lungs. Additionally, TSA suppressed lavage tumor necrosis factor-α and cytokine-induced neutrophil chemoattractant concentrations, cell infiltration, and myeloperoxidase-positive cells in the lung tissue. Furthermore, TSA attenuated the phosphorylation of extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase, degradation of the inhibitor of nuclear factor (NF)-κB, and nuclear NF-κB levels. TSA also decreased poly (ADP-ribose) polymerase but enhanced acetylated histone H3 acetylation, Bcl-2, and mitogen-activated protein kinase phosphatase-1 (MKP-1) expression in IR lung tissue. Therefore, TSA exerted a protective effect on IR-induced lung injury via increasing histone acetylation and MKP-1 protein expression, repressing NF-κB, mitogen-activated protein kinase, and apoptosis signaling pathways.

Systemic Administration of FC-77 Dampens Ischemia–Reperfusion-Induced Acute Lung Injury in Rats

Systemic administration of perfluorocarbons (PFCs) reportedly attenuates acute lung injury induced by acid aspiration and phorbol myristate acetate. However, the effects of PFCs on ischemia–reperfusion (IR)-induced lung injury have not been investigated. Typical acute lung injury was induced in rats by 60 min of ischemia and 60 min of reperfusion in isolated and perfused rat lung model. Rat lungs were randomly assigned to receive PBS (control), 1 % FC-77, IR only, or IR with different doses of FC-77 (0.1 %, 0.5 %, or 1 %). Subsequently, bronchoalveolar lavage fluid (BALF), perfusate, and lung tissues were collected to evaluate the degree of lung injury. IR caused a significant increase in the following parameters: pulmonary arterial pressure, capillary filtration coefficient, lung weight gain, lung weight/body weight ratio, wet/dry lung weight ratio, and protein concentration in BALF. TNF-α and cytokine-induced neutrophil chemoattractant-1 concentrations in perfusate samples and MDA concentration and MPO activities in lung tissues were also significantly increased. Histopathology showed increased septal thickness and neutrophil infiltration in the lung tissues. Furthermore, NF-κB activity was significantly increased in the lungs. However, pretreatment with 1 % FC-77 prior to IR significantly attenuated the increases in these parameters. In conclusion, our results suggest that systemic FC-77 administration had a protective effect on IR-induced acute lung injury. These protective mechanisms may have been mediated by the inhibition of NF-κB activation and attenuation of subsequent inflammatory response.

Pulmonary toxicity of well-dispersed single-wall carbon nanotubes after inhalation

Single-wall carbon nanotubes (SWCNTs) were well-dispersed by ultrasonication to conduct an inhalation study. SWCNTs were generated using a pressurised nebuliser with liquid suspension of SWCNTs. Wistar rats were exposed to the well-dispersed SWCNT (diameter of bundle: 0.2 μm; length of bundle: 0.7 μm) for 4 weeks. The low and high mass concentrations of SWCNTs were 0.03 ± 0.003 and 0.13 ± 0.03 mg/m3, respectively. The rats were sacrificed at 3 days, 1 month, and 3 months after the end of exposure. There were no increases of total cell or neutrophil counts in the bronchoalveolar lavage fluid (BALF), or the concentration of cytokine-induced neutrophil chemoattractant in the lungs or BALF in both the high and low concentration-exposed groups. Pulmonary infiltration of neutrophils was not observed in either exposed group throughout the observation period. Well-dispersed SWCNT did not induce neutrophil inflammation in the lung under the conditions in the present study.

Effect of valproic acid on acute lung injury in a rodent model of intestinal ischemia reperfusion

ObjectivesAcute lung injury (ALI) can develop during the course of many clinical conditions, and is associated with significant morbidity and mortality. Valproic acid (VPA), a well-known anti-epileptic drug, has been shown to have anti-oxidant and anti-inflammatory effects in various ischemia/reperfusion (I/R) models. The purpose of this study was to investigate whether VPA could affect survival and development of ALI in a rat model of intestinal I/R. MethodsTwo experiments were performed. Experiment I: Male Sprague-Dawley rats (250–300g) were subjected to intestinal ischemia (1h) and reperfusion (3h). They were randomized into 2 groups (n=7 per group) 30min after ischemia: Vehicle (Veh) and VPA (300mg/kg, IV). Primary end-point for this study was survival over 4h from the start of ischemia. Experiment II: The histological and biochemical effects of VPA treatment on lungs were examined 3h (1h ischemia+2h reperfusion) after intestinal I/R injury (Veh vs. VPA, n=9 per group). An objective histological score was used to grade the degree of ALI. Enzyme linked immunosorbent assay (ELISA) was performed to measure serum levels of interleukins (IL-6 and 10), and lung tissue of cytokine-induced neutrophil chemoattractant (CINC) and myeloperoxidase (MPO). In addition, the activity of 8-isoprostane was analyzed for pulmonary oxidative damage. ResultsIn Experiment I, 4-h survival rate was significantly higher in VPA treated animals compared to Veh animals (71.4% vs. 14.3%, p=0.006). In Experiment II, ALI was apparent in all of the Veh group animals. Treatment with VPA prevented the development of ALI, with a reduction in the histological score (3.4±0.3 vs. 5.3±0.6, p=0.025). Moreover, compared to the Veh control group the animals from the VPA group displayed decreased serum levels of IL-6 (952±213pg/ml vs. 7709±1990pg/ml, p=0.011), and lung tissue concentrations of CINC (1188±28pg/ml vs. 1298±27pg/ml, p<0.05), MPO activity (368±23ng/ml vs. 490±29ng/ml, p<0.05) and 8-isoprostane levels (1495±221pg/ml vs. 2191±177pg/ml, p<0.05). ConclusionVPA treatment improves survival and attenuates ALI in a rat model of intestinal I/R injury, at least in part, through its anti-oxidant and anti-inflammatory effects.

Olprinone decreases elevated concentrations of cytokine-induced neutrophil chemoattractant-1 in septic rats

The diaphragm is one of the organs directly affected by abdominal sepsis. Evidence suggests that sepsis induces diaphragmatic fatigability and that activated neutrophils play a crucial role in the development of diaphragmatic fatigability. In the present study, we investigated whether olprinone, a phosphodiesterase inhibitor, influenced the kinetics of cytokine-induced neutrophil chemoattractant-1 (CINC-1) in the diaphragm under abdominal septic conditions. Male Wistar rats were randomly assigned to a sham group, a cecal ligation and perforation group, and a phosphodiesterase inhibitor-pretreated group. To measure serial changes in CINC-1 concentrations, the right hemidiaphragm was removed at 4, 8, and 16 h after the surgical procedure in each group. In the cecal ligation and perforation group, CINC-1 concentrations in the diaphragm were significantly elevated compared with those in the sham group at both 4 and 8 h after the cecal ligation and perforation procedure. In the phosphodiesterase inhibitor-pretreated group, olprinone significantly attenuated the elevated CINC-1 concentrations at both 4 and 8 h after the surgical procedure. However, we observed no statistically significant differences in CINC-1 concentrations between the cecal ligation and perforation group and the phosphodiesterase inhibitor-pretreated groups at 16 h after the surgical procedure. Olprinone decreases elevated CINC-1 concentration in the diaphragm under septic conditions. This suggests that olprinone may inhibit neutrophil recruitment to the diaphragm.

Cytosolic Phospholipase A2 Activity in Neutrophilic Oxidative Stress of Platelet-activating Factor-induced Acute Lung Injury

Background: The present investigation was performed in rats and isolated human neutrophils in order to confirm the presumptive role of the positive feedback loop of cytosolic phospholipase () activation by plateletactivating factor (PAF). Methods: The possible formation of the positive feedback loop of the activation and neutrophilic respiratory burst was investigated in vivo and in vitro by measurement of the parameters denoting acute lung injury. In addition, morphological examinations and electron microscopic cytochemistry were performed for the detection of free radicals in the lung. Results: Five hours after intratracheal instillation of PAF (), the lung leak index, lung myeloperoxidase (MPO) activity, the number of neutrophils and the concentration of cytokine-induced neutrophil chemoattractant (CINC) in bronchoalveolar lavage fluid were increased by PAF as compared with those of control rats. The NBT assay and cytochrome-c reduction assay revealed an increased neutrophilic respiratory burst in isolated human neutrophils following exposure to PAF. Lung and neutrophilic activity were increased following PAF exposure and exposure to hydrogen peroxide increased activity in the lung. Histologically, inflammatory findings of the lung were observed after PAF treatment. Remarkably, as determined by cytochemical electron microscopy, increased production of hydrogen peroxide was identified in the lung after PAF treatment. Conclusion: PAF mediates acute oxidative lung injury by the activation of , which may provoke the generation of free radicals in neutrophils.

Pentoxifylline Attenuates Lung Injury and Modulates Transcription Factor Activity in Hemorrhagic Shock

Evidence exists that resuscitation with Ringer's lactate (RL) contributes to postshock inflammation and lung injury. We hypothesized that the anti-inflammatory agent pentoxifylline (PTX) attenuates postresuscitative lung injury through modulation of transcription factors after hemorrhagic shock. Male Sprague Dawley rats underwent a 1 h period of hypotension and resuscitation with RL (32 mL/kg) or RL + PTX (25 mg/kg). Lung sections were graded for histological injury and myeloperoxidase content. Cytokine-induced neutrophil chemoattractant concentration was determined by enzyme immunoassay. Matrix metalloproteinase-2 and -9 (MMP) activity was evaluated by zymography. Heme oxygenase-1, nuclear factor kappa B (NF-kappaB) p65 nuclear translocation, and cytoplasmic I-kappaB phosphorylation were assessed by Western blot. NF-kappaB and cAMP response element binding protein (CREB) DNA binding were determined by light shift chemiluminescent electrophoretic mobility shift assay. RL resuscitation led to statistically significant increases in all parameters of lung injury when compared with the negative control. The addition of PTX significantly decreased histology lung injury, myeloperoxidase content, cytokine-induced neutrophil chemoattractant by 48% (P < 0.05), heme oxygenase-1 expression by 50% (P < 0.05), MMP-2 activity by 70% (P < 0.05), MMP-9 activity by 44% (P < 0.05), cytoplasmic I-kappaB phosphorylation by 66% (P < 0.01), nuclear NF-kappaB p65 phosphorylation by 51% (P < 0.05), and NF-kappaB DNA binding by 42% (P < 0.05). In contrast, PTX increased CREB DNA binding by 69% when compared with RL alone (P < 0.04). The addition of PTX to conventional RL infusion after shock significantly reduced histological lung injury and pulmonary neutrophil activity when compared to treatment with RL alone. The administration of PTX was also associated with diminished NF-kappaB and enhanced CREB activation. Therefore, the administration of PTX may serve as a novel therapeutic adjunct after hemorrhagic shock.

Inhibitory effect of d-allose on neutrophil activation after rat renal ischemia/reperfusion

D-Allose is one of the rare sugars produced from D-psicose. We examined whether d-allose reduces the extent of rat renal ischemia/reperfusion (I/R) injury by suppressing the activation of neutrophils. The renal concentrations of cytokine-induced neutrophil chemoattractant (CINC)-1 and myeloperoxidase were significantly increased after renal I/R. These increases were significantly inhibited by D-allose administration. Furthermore, D-allose significantly inhibited the increase in the concentrations of blood urea nitrogen (BUN), creatinine, N-acetyl beta-D-glucosaminidase (NAG) and histopathologic changes after renal I/R. These findings strongly suggest that D-allose protects against I/R-induced renal injury by inhibiting the activation of neutrophils that play an important role in I/R-induced renal injury. These findings may have important implications in understanding the biologic functions of D-allose. D-Allose may prove useful in renal surgery and transplantation.

Role of Steroid Administration to Reduce Inflammation After Thoracotomy in a Rat Surgical Stress Model

Unilateral lung surgical insult can lead to bilateral pulmonary inflammation after transthoracic esophagectomy for esophageal cancer. An inflammatory response of the cytokine network induced by surgical stress followed by neutrophil sequestration is the major mechanism involved in these complications. We examined modulation of the inflammatory cytokine and neutrophil sequestration by preoperative steroid administration in a rat thoracotomy model. Adult male rats were subjected to right thoracotomy with pulmonary compression in the surgical stress model. In the another surgical stress model, 10 mg/kg of methylprednisolone (MP) was administered 1 h before the operation intraperitoneally, and peri-operative biological effects of steroid administration to neutrophil sequestration and cytokine-induced neutrophil chemoattractant (CINC) as an inflammatory cytokine were examined. Sham-operated animals were subjected to intubation only. Surgical insult to the unilateral lung increased local CINC concentration followed by an increase in neutrophil sequestration, wet-to-dry weight ratio in bilateral lungs and systemic CINC concentration. Pre-treatment with methylprednisolone reduced CINC concentration as well as neutrophil sequestration and wet-to-dry weight ratio of both lungs. These data suggest that inflammatory changes induced by the unilateral operative procedure occur in both lungs through local inflammatory response. Pre-operative methylprednisolone administration down-regulates cytokine release and neutrophil sequestration, preventing lung edema, and possibly may act as a prophylactic treatment against acute lung injury caused by a so-called "second attack" theory.

The protective effect of heat shock protein 72 by Doxorubicin in cold ischemia-reperfusion injury of the rat liver

To observe induction of heat shock reaction by pretreatment of Doxorubicin (DXR) in long-term cold preservation-reperfusion injury of the rat liver. The rats were administered intravenously by DXR at a dose of 1 mg/kg body weight in DXR group and by saline in control group. After 48 hours, the rat liver was perfused by using cold University of Wisconsin (UW) solutions and was preserved in UW solution at 4 degrees C for 48 hours. Recipient liver was perfused for 1 and 3 hours after orthotopic liver transplantation. Tumor necrosis factor-alpha (TNF-alpha) mRNA, cytokine-induced neutrophil chemoattractant (CINC) mRNA, macrophage inflammatory protein (MIP-2) mRNA was measured by RT-PCR and heat shock protein 72 (HSP72), nuclear factor-kappaB (NF-kappaB) by Western blot. The serum levels of TNF-alpha, CINC, MIP-2 by ELISA and AST were measured. The survival rate of 7 days was observed. The expression of TNF-alpha mRNA, CINC mRNA and MIP-2 mRNA was stronger in control group than in DXR group. HSP72 was expressed in SA group but not in control group and oppositely NF-kappaB was expressed in control group but not in DXR group. Serum AST, TNF-alpha, CINC and MIP-2 concentrations were significantly lower in DXR group than in control group (P < 0.05). The survival rate of 7 days was significantly higher in DXR group than in control group (50% vs. 0%, P < 0.05). These data suggested that long-term cold ischemia-reperfusion injury was attenuated in liver graft with pretreatment of DXR. The induction of HSP72 may offer protection to hepatocytes by restraining the activation of NF-kappaB and inflammation.

Ascorbic Acid Deficiency Stimulates Hepatic Expression of Inflammatory Chemokine, Cytokine-Induced Neutrophil Chemoattractant-1, in Scurvy-Prone ODS Rats

ODS rat has a hereditary defect in ascorbic acid biosynthesis and is a useful animal model for elucidating the physiological role of ascorbic acid. We previously demonstrated by using ODS rats that ascorbic acid deficiency changes the hepatic gene expression of acute phase proteins, as seen in acute inflammation. In this study, we investigated the effects of ascorbic acid deficiency on the production of inflammatory chemokine, cytokine-induced neutrophil chemoattractant-1 (CINC-1), in ODS rats. Male ODS rats (6 wk of age) were fed a basal diet containing ascorbic acid (300 mg/kg diet) or a diet without ascorbic acid for 14 d. Obvious symptoms of scurvy were not observed in the ascorbic acid-deficient rats. Ascorbic acid deficiency significantly elevated the serum concentration of CINC-1 on d 14. The liver and spleen CINC-1 concentrations in the ascorbic acid-deficient rats were significantly elevated to 600% and 180% of the respective values in the control rats. However, the lung concentration of CINC-1 was not affected by ascorbic acid deficiency. Ascorbic acid deficiency significantly elevated the hepatic mRNA level of CINC-1 (to 480% of the value in the control rats), but not the lung mRNA level. These results demonstrate that ascorbic acid deficiency elevates the serum, liver and spleen concentrations of CINC-1 as seen in acute inflammation, and suggest that ascorbic acid deficiency stimulate the hepatic CINC-1 gene expression.

Inosine alleviates rat caerulein pancreatitis and pancreatitis-associated lung injury.

Recent studies have shown that inosine, a purine nucleoside produced during the breakdown of adenosine, has immunomodulatory and anti-inflammatory properties. The aim of this study was to examine the effects of inosine on the course of acute pancreatitis. Edematous pancreatitis was induced by the intraperitoneal injection of caerulein (50 micro g/kg), seven times, at 1-h intervals, in male Wistar rats (caerulein pancreatitis). Inosine (100 mg/kg) was administered 30 min before or 1 h after the first injection of caerulein. The effects of inosine on the severity of pancreatitis were assessed by serum amylase, pancreatic edema (wet/dry ratio), myeloperoxidase activity, cytokine-induced neutrophil chemoattractant-1 concentrations, and histological changes. Prophylactic administration of inosine significantly decreased the elevation of serum amylase, myeloperoxidase activity, and cytokine-induced neutrophil chemoattractant-1 concentrations in the pancreas and the lung. Inosine did not significantly affect edema formation. Histologically, vacuole formation in pancreatic acinar cells, infiltration of inflammatory cells in the pancreas and the lung, and alveolar wall thickening in the lung were reduced. Inosine improved the histological findings and reduced myeloperoxidase activity even if it was administered 1 h after the first injection of caerulein. Inosine reduced the severity of acute pancreatitis, suggesting a possible application of this compound in the treatment of acute pancreatitis.

Edaravone, a newly developed radical scavenger, protects against ischemia-reperfusion injury of the small intestine in rats

Although edaravone (3-methyl-1-phenyl-pyrazolin-5-one), a newly developed radical scavenging agent, has been widely used for protection against ischemia-reperfusion (I-R) injury in patients with cerebral infarction, its effects on gastrointestinal I-R injury have not been evaluated. In the present study, we examined the effects of edaravone on experimental intestinal I-R damage in rats. In male Wistar rats with and without edaravone treatment, intestinal damage was induced by clamping the superior mesenteric artery for 30 min, followed by reperfusion. Edaravone was administered via intravenous infusion at 5 min before reperfusion was achieved by removal of the clamp. The rats were sacrificed after 60 min of reperfusion. Luminal protein and hemoglobin concentrations were measured as an index of mucosal injury and histological examination of hematoxylin and eosin-stained sections was performed. Thiobarbituric acid (TBA)-reactive substances and tissue-associated myeloperoxidase (MPO) activity were measured in the mucosa as indicators of lipid peroxidation and neutrophil infiltration, respectively. The mucosal concentration of cytokine-induced neutrophil chemoattractant (CINC)-1 (a member of the IL-8 family) was determined by enzyme-linked immunosorbent assay (ELISA). Additionally, CINC-1 messenger RNA (mRNA) was measured by the reverse-transcription polymerase chain reaction (RT-PCR). As a result, the levels of luminal protein and hemoglobin, TBA-reactive substances, and MPO activity were all increased significantly by I-R injury, and these increases were significantly inhibited by treatment with edaravone. Multiple erosions and bleeding were observed macroscopically after the small intestine was exposed to I-R injury, and these changes were inhibited by administration of edaravone. Microscopic I-R damage was also reduced by treatment with edaravone. CINC-1 protein and CINC-1 mRNA were both increased by I-R injury, while edaravone markedly reduced the levels of both protein and mRNA. In summary, these results suggest that edaravone can protect the small intestine against I-R injury by scavenging oxygen-derived free radicals.

Neutrophil modulation of the pulmonary chemokine response to lipopolysaccharide.

When cells within the intrapulmonary compartment are exposed to pathogens or their products such as lipopolysaccharide, they produce CXC chemokines in order to attract circulating neutrophils into the lower respiratory tract. Previous studies have shown that as neutrophils (PMNs) enter the lung, bronchoalveolar lavage (BAL) chemokine levels are decreased. In this study, we determined the intrapulmonary and systemic responses to two important rat chemokines, cytokine-induced neutrophil chemoattractant (CINC) and macrophage inflammatory protein-2 (MIP-2), to intratracheal (i.t.) LPS (100 microg in 0.5 mL of phosphate-buffered saline) under neutropenic (cyclophosphamide [CPA]) and neutrophilic (G-CSF) conditions. By 4 h after i.t. LPS, CPA pretreatment decreased PMN recruitment 83% and G-CSF increased PMN recruitment 91% compared with recruitment into the lung in vehicle-pretreated rats (42.7 +/- 19.3 million PMNs). Neutropenic rats had increased CINC and MIP-2 concentrations in BAL fluid 4 h after i.t. LPS when compared with levels seen in vehicle controls (P < 0.05). In vitro LPS-stimulated chemokine production by alveolar macrophages obtained from CPA- and vehicle-pretreated animals did not differ. The increase in BAL fluid chemokine levels in neutropenic rats corresponded to increased chemotaxis of neutrophils to BAL fluid from CPA-pretreated rats as compared with the chemotaxis response of PMN to BAL fluid from vehicle-pretreated rats. In contrast, G-CSF enhancement of neutrophil recruitment decreased chemotactic activity of BAL fluid collected 4 h after i.t. LPS. These data show that as neutrophils are recruited into the lung, they alter chemokine levels, which most likely serves to down-regulate the inflammatory response.

Compartmentalization of macrophage inflammatory protein-2, but not cytokine-induced neutrophil chemoattractant, in rats challenged with intratracheal endotoxin.

An important feature of the pulmonary inflammatory response is that the production of certain cytokines and chemokines is largely confined to the lung. This study investigated the local and systemic responses of macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (CINC) in rats administered with either intratracheal or intravenous lipopolysaccharide (LPS). Intratracheal LPS induced a significant increase in MIP-2 in bronchoalveolar lavage (BAL) fluid with no detectable MIP-2 in the plasma. In contrast, CINC was significantly increased in both BAL fluid and the plasma after intratracheal LPS challenge. Cell-associated MIP-2 was increased in the pulmonary-recruited neutrophils (PMNs) but not in the circulating PMNs in rats given intratracheal LPS. Cell-associated CINC was increased in both the recruited and circulating PMNs in these animals. Intravenous LPS caused a marked increase in plasma MIP-2 and CINC, whereas only a small elevation of both MIP-2 and CINC concentrations in BAL fluid was observed. The lack of CINC compartmentalization compared to MIP-2 implies that these C-X-C chemokines are regulated differentially and may have different effects upon polymorphonuclear leukocyte (PMN) recruitment into the alveolar space in response to intrapulmonary LPS or bacterial challenge.

Effect of Neutrophil Elastase inhibitor, ICI 200,355, on Interleukin-1 Induced acute lung injury in rats

Background: Interleukin-1(IL-1) and neutrophil appear to contribute to the pathogenesis of acute respiratory distress syndrome(ARDS). Elastase, as well as reactive oxygen species released from activated neutrophil, are thought to play pivotal roles in the experimental models of acute lung leak. This study investigated whether ICI 200,355, a synthetic elastase inhibitor, can attenuate acute lung injury induced by IL-1 in rats. Materials and Methods: We intratracheally instilled either saline or IL-1 with and without treatment of ICI 200,355 in rats. Lung lavage neutrophils, lung lavage cytokine-induced neutrophil chemoattractant(CINC) concentration, lung lavage protein concentration, lung myeloperoxidase(MPO) activity and lung leak index were measured at 5 hours of intratracheal treatment. Results: In rats given IL-1 intratracheally, lung lavage neutrophils, lung lavage CINC concentration, lung lavage protein concentration, lung MPO activity and lung leak index were higher. Intratracheal ICI 200,355 administration decreased lung lavage neutrophils, lung MFO activity and lung leak index, respectively, but did not decrease lung lavage CINC concentration. Conclusion: These results suggest that ICI 200,355 decreases lung inflammation and leak without decreasing lung lavage CINC concentration in rats given IL-1 intratracheally.

Acute Alcohol Intoxication Suppresses the CXC Chemokine Response During Endotoxemia

CXC chemokines play an important role in host defense against infections. Alcohol is a frequently abused drug that inhibits numerous immune functions of the host. This study investigated the effects of alcohol on CXC chemokine macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (CINC) responses in rats challenged with intravenous lipopolysaccharide (LPS). Acute ethanol intoxication was induced by an intraperitoneal injection of 20% alcohol (5.5 g/kg). Thirty minutes thereafter, LPS (500 microg/kg) was administered intravenously. In another set of experiments, rats were intravenously administered an anti-tumor necrosis factor-alpha (TNFalpha) neutralizing antibody (10 mg per rat) 2 hr before the LPS challenge. At 1 and 2 hr after the LPS challenge, MIP-2, CINC, and TNFalpha concentrations in the plasma were significantly increased. Alcohol intoxication suppressed the MIP-2, CINC, and TNFalpha responses in the bloodstream during endotoxemia. Alcohol also suppressed the increase in plasma chemotactic activity and polymorphonuclear leukocyte adhesion molecule expression in rats with endotoxemia. MIP-2 and CINC messenger RNA (mRNA) expression was significantly increased 1 hr after endotoxemia in the lung, liver, and spleen. Alcohol suppressed the up-regulation of MIP-2 mRNA expression in all of these organs and CINC mRNA expression in the lungs of rats with endotoxemia. TNFalpha neutralization minimally inhibited plasma CINC and MIP-2 responses during endotoxemia and did not suppress the increase in plasma chemotactic activity. These results show that alcohol suppresses the systemic CXC chemokine response to LPS, which is not primarily mediated by ethanol-induced suppression of TNFalpha. This disruption of host-defense function may serve as one mechanism underlying the increased risk of infectious diseases in hosts who abuse alcohol.