scholarly journals Arachidonic acid in postshock mesenteric lymph induces pulmonary synthesis of leukotriene B4

2008 ◽  
Vol 104 (4) ◽  
pp. 1161-1166 ◽  
Author(s):  
Janeen R. Jordan ◽  
Ernest E. Moore ◽  
Eric L. Sarin ◽  
Sagar S. Damle ◽  
Sara B. Kashuk ◽  
...  

Mesenteric lymph is the mechanistic link between splanchnic hypoperfusion and acute lung injury (ALI), but the culprit mediator(s) remains elusive. Previous work has shown that administration of a phospholipase A2(PLA2) inhibitor attenuated postshock ALI and also identified a non-ionic lipid within the postshock mesenteric lymph (PSML) responsible for polymorphonuclear neutrophil (PMN) priming. Consequently, we hypothesized that gut-derived leukotriene B4(LTB4) is a key mediator in the pathogenesis of ALI. Trauma/hemorrhagic shock (T/HS) was induced in male Sprague-Dawley rats and the mesenteric duct cannulated for lymph collection/diversion. PSML, arachidonic acid (AA), and a LTB4receptor antagonist were added to PMNs in vitro. LC/MS/MS was employed to identify bioactive lipids in PSML and the lungs. T/HS increased AA in PSML and increased LTB4and PMNs in the lung. Lymph diversion decreased lung LTB4by 75% and PMNs by 40%. PSML stimulated PMN priming (11.56 ± 1.25 vs. 3.95 ± 0.29 nmol O2−/min; 3.75 × 105cells/ml; P < 0.01) that was attenuated by LTB4receptor blockade (2.64 ± 0.58; P < 0.01). AA stimulated PMNs to produce LTB4, and AA-induced PMN priming was attenuated by LTB4receptor antagonism. Collectively, these data indicate that splanchnic ischemia/reperfusion activates gut PLA2-mediated release of AA into the lymph where it is delivered to the lungs, provoking LTB4production and subsequent PMN-mediated lung injury.

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Liangrong Wang ◽  
Baihui Chen ◽  
Bi Lin ◽  
Yuzhu Ye ◽  
Caiying Bao ◽  
...  

Objective. This study was aimed to investigate the protective effect of methylene blue against lung injury induced by reperfusion of ischemic hindlimb in a rat model. Methods. Twenty-four healthy adult male Sprague-Dawley rats were equally randomized into three groups: sham (SM) group, ischemia reperfusion (IR) group, and methylene blue (MB) group. Rats in both IR and MB groups were subjected to 4 h of ischemia by clamping the left femoral artery and then followed by 4 h of reperfusion. Treatment with 1% methylene blue (50 mg/kg) was administrated intraperitoneally at 10 min prior to reperfusion in the MB group. After 4 h of reperfusion, malondialdehyde (MDA) level, myeloperoxidase (MPO), and superoxide dismutase (SOD) activities in lung tissue were detected; inflammatory cytokines, including IL-1β and IL-6, were measured in bronchoalveolar lavage fluid (BALF); correspondingly, the morphological changes and water content in both gastrocnemius muscle and lung samples were evaluated. Results. Hindlimb IR caused remarkable morphological abnormalities and edema in both muscle and lung tissues. SOD activity was decreased, both the MPO activity and MDA level in lung tissue, as well as IL-1β and IL-6 levels in BALF, were increased in the IR group (p<0.05). Compared with the IR group, SOD activity was increased, whereas MPO activity and MDA level in lung tissue and IL-1β and IL-6 levels in BALF were decreased in the MB group (p<0.05). Also, the histological damage and edema in both lung and muscle tissues were significantly attenuated by the treatment of methylene blue. Conclusion. Methylene blue attenuates lung injury induced by hindlimb IR in rats, at least in part, by inhibiting oxidative stress.


1989 ◽  
Vol 5 (3) ◽  
pp. 451-461 ◽  
Author(s):  
Robert L. Sherwood ◽  
Peter T. Thomas ◽  
William J. O'shea ◽  
Jeannie N. Bradof ◽  
Helen V. Ratajczak ◽  
...  

Pulmonary bactericidal activity, macrophage phagocytic activity, alveolar macrophage (AM) enzyme activity, and T- and B-cell mitogenesis of lymphocytes from lung associated lymph nodes (LALN) or mesenteric lymph nodes (MESLN) were assessed in Sprague-Dawley rats exposed 4 hr/d, 4 days/wk for 1, 4, or 16 days to hexachlorobenzene (HCB) aerosols. Pulmonary bactericidal activity was depressed after 1 or 4 but not 16 exposures to 35 mg/m3 of HCB. AM phagocytosis of 51Cr-RBC in vitro was increased after 4 but not 1 or 16 exposures to HCB, and no effect was observed in peritoneal macrophages. HCB significantly enhanced mitogenesis in MESLN to the B-cell mitogen Salmonella typhimurium lipopolysaccharide (STM) after 4 exposures; LALN STM mitogenesis and LALN and MESLN mitogenesis to phytohemagglutinin (PHA) were not affected. After 16 exposures, however, the PHA responses in LALN and MESLN were significantly increased and decreased, respectively.


2017 ◽  
Vol 313 (5) ◽  
pp. E577-E585 ◽  
Author(s):  
Tingting Li ◽  
Jie Xu ◽  
Xinghua Qin ◽  
Zuoxu Hou ◽  
Yongzheng Guo ◽  
...  

Myocardial reperfusion decreases glucose oxidation and uncouples glucose oxidation from glycolysis. Therapies that increase glucose oxidation lessen myocardial ischemia-reperfusion (I/R) injury. However, the regulation of glucose uptake during reperfusion remains poorly understood. We found that glucose uptake was remarkably diminished in the myocardium following reperfusion in Sprague-Dawley rats as detected by 18F–labeled and fluorescent-labeled glucose analogs, even though GLUT1 was upregulated by threefold and GLUT4 translocation remained unchanged compared with those of sham-treated rats. The decreased glucose uptake was accompanied by suppressed glucose oxidation. Interestingly, stimulating glucose oxidation by inhibition of pyruvate dehydrogenase kinase 4 (PDK4), a rate-limiting enzyme for glucose oxidation, increased glucose uptake and alleviated I/R injury. In vitro data in neonatal myocytes showed that PDK4 overexpression decreased glucose uptake, whereas its knockdown increased glucose uptake, suggesting that PDK4 has a role in regulating glucose uptake. Moreover, inhibition of PDK4 increased myocardial glucose uptake with concomitant enhancement of cardiac insulin sensitivity following myocardial I/R. These results showed that the suppressed glucose oxidation mediated by PDK4 contributes to the reduced glucose uptake in the myocardium following reperfusion, and enhancement of glucose uptake exerts cardioprotection. The findings suggest that stimulating glucose oxidation via PDK4 could be an efficient approach to improve recovery from myocardial I/R injury.


1994 ◽  
Vol 76 (2) ◽  
pp. 545-552 ◽  
Author(s):  
K. Hsu ◽  
D. Wang ◽  
S. Y. Wu ◽  
C. Y. Shen ◽  
H. I. Chen

The protective effect of ATP-MgCl2 on ischemia-reperfusion lung injury has been reported in kidney, liver, heart, and muscle but has not been examined in lungs. The aim of this study was to determine whether ATP or ATP-MgCl2 pretreatment would attenuate ischemia-reperfusion-induced acute lung injury and to identify the possible mechanisms for such protection. Typical acute lung injury was successfully induced in Sprague-Dawley rats by 10 min of hypoxia followed by 75 min of ischemia and 50 min of reperfusion. Pretreatment with ATP-MgCl2 (or adenosine) but not ATP or MgCl2 (all at 10(-6) M) significantly attenuated the acute lung injury. All the protective effects of ATP-MgCl2 were nearly undetectable when promazine (an ecto-adenosinetriphosphatase inhibitor) or 3,7-dimethyl-1-propargylxanthine (an A2-receptor antagonist) was added before ATP-MgCl2 pretreatment. These observations support our hypothesis that the protective effect of ATP-MgCl2 is in part mediated through adenosine, the degradation product of ATP, which is produced by the Mg(2+)-dependent ecto-adenosinetriphosphatase on the surface of neutrophils and reacts with neutrophil A2 receptors to inhibit the production of O2 radicals.


2020 ◽  
Vol 21 (17) ◽  
pp. 6353
Author(s):  
Zrinka Mihaljević ◽  
Anita Matić ◽  
Ana Stupin ◽  
Ruža Frkanec ◽  
Branka Tavčar ◽  
...  

Acetylcholine-induced vasorelaxation (AChIR) and responses to reduced pO2 (hypoxia-induced relaxation (HIR), 0% O2) were assessed in vitro in aortic rings of healthy male Sprague-Dawley rats (N = 252) under hyperbaric (HBO2) protocols. The studied groups consisted of the CTRL group (untreated); the A-HBO2 group (single HBO2; 120 min of 100% O2 at 2.0 bars); the 24H-HBO2 group (examined 24 h after single exposure) and the 4D-HBO2 group (four consecutive days of single HBO2). AChIR, sensitivity to ACh and iNOS expression were decreased in the A-HBO2 group. HIR was prostanoid- and epoxyeicosatrienoic acid (EET)-mediated. HIF-1α expression was increased in the 24H-HBO2 and 4D-HBO2 groups. LW6 (HIF-1α inhibitor) decreased HIR in the 24H-HBO2 group. HBO2 affected the expression of COX-1 and COX-2. CYP2c11 expression was elevated in the 24H-HBO2 and 4D-HBO2 groups. Concentrations of arachidonic acid (AA) metabolites 14(15)-DiHET, 11(12)-DiHET and 8(9)-DiHET were increased in A-HBO2 and 24H-HBO2. An increased concentration of 8(9)-EET was observed in the A-HBO2 and 24h-HBO2 groups vs. the CTRL and 4D-HBO2 groups, and an increased concentration of 5(6)-DiHET was observed in the 24H-HBO2 group vs. the 4D-HBO2 group. The 20-HETE concentration was increased in the A-HBO2 group. All were determined by LC-MS/MS of the aorta. The results show that AChIR in all groups is mostly NO-dependent. HIR is undoubtedly mediated by the CYP450 enzymes’ metabolites of AA, whereas HIF-1α contributes to restored HIR. Vasoconstrictor metabolites of CYP450 enzymes contribute to attenuated AChIR and HIR in A-HBO2.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Himanshu Kushwah ◽  
Nidhi Sandal ◽  
Meenakshi Chauhan ◽  
Gaurav Mittal

Abstract Background Uncontrolled bleeding is one of the primary reasons for preventable death in both civilian trauma and military battle field. This study evaluates in vitro and in vivo hemostatic potential of four biopolymeric natural gums, namely, gum tragacanth, guar gum, xanthan gum, and gum acacia. In vitro evaluation of whole blood clotting time and erythrocyte agglutination assay were carried out. In vitro cytotoxicity studies with respect to each gum were done in human lymphocytes to ascertain percent cell viability. In vivo hemostatic potential of each gum (as sponge dressing and powder form) was evaluated in Sprague Dawley rats using tail bleeding assay and compared with commercially available hemostatic sponge. Other important parameters like (a) time taken for complete hemostasis, (b) amount of blood absorbed, (c) adherence strength of developed hemostatic dressing(s), (d) incidence of re-bleeding, and (e) survival of animals were also studied. Results Of the four test gums studied, xanthan gum (@3mg/ml of blood) and gum tragacanth (@35mg/ml of blood) were able to clot blood in least time (58.75±6.408 s and 59.00±2.082 s, respectively) and exhibited very good hemostatic potential in vitro. Except for xanthan gum, all other test gums did not exhibit any significant cytotoxicity at different time points till 24 h. In rat tail bleeding experiments, gum tragacanth sponge dressing and powder achieved hemostasis in least time (156.2±12.86 s and 76±12.55 s, respectively) and much earlier than commercially available product (333.3±38.84 s; p˂0.01). Conclusion Results indicate potential of gum tragacanth to be developed into a suitable hemostatic product.


1991 ◽  
Vol 7 (3) ◽  
pp. 125-139 ◽  
Author(s):  
David R. Bevan ◽  
David M. Ruggio

To evaluate health risks associated with exposure to particulates in the environment, it is necessary to quantify the bioavailability of carcinogens associated with the particulates. Direct analysis of bioavailability in vivo is most readily accomplished by adsorbing a radiolabeled form of the carcinogen to the particulate. A sam ple of native diesel particulate collected from an Oldsmobile die sel engine that contained 1.03 μ g benzo[ a] pyrene ( BaP)/ g particulate was supplemented with exogenous [ 3 H]- BaP to pro duce a particulate containing 2.62 μ g BaP/g. To insure that elu tion of BaP from native and [3 H] -BaP-supplemented particulate was similar, in vitro analyses were performed. When using phos pholipid vesicles composed of dimyristoylphosphatidylcholine (DMPC), 1.52% of total BaP was eluted from native particulate into the vesicles in 18 hrs; from [ 3 H] -BaP supplemented particu late, 1.68% was eluted. Using toluene as eluent, 2.55% was eluted from native particulate, and 8.25% from supplemented particulate, in 6 hrs. Supplemented particulate was then instilled intratracheally into male Sprague-Dawley rats and distribution of radioactivity was analyzed at selected times over 3 days. About 50% of radioactivity remained in lungs at 3 days following instil lation, with 30% being excreted into feces and the remainder dis tributed throughout the organs of the rats. To estimate the amount of radioactivity that entered feces through swallowing of a portion of the instilled dose, [3 H] -BaP-supplemented particu late was instilled intratracheally into rats that had a cannula sur gically implanted in the bile duct. Rate of elimination of radio activity into bile was monitored; 10.6% of radioactivity was re covered in 6 hr, an amount slightly lower than the 12.8% ex creted in 6 hrs into feces of animals with intact bile ducts. Our studies provide a quantitative description of the distribution of BaP and its metabolites following intratracheal instillation of diesel particulate. Because rates of elution of BaP in vitro are similar for native diesel particulate and particulate with supple mental [ 3H] -BaP, our results provide a reasonable estimate of the bioavailability in vivo of BaP associated with diesel particu late.


2013 ◽  
Vol 32 (5) ◽  
pp. 385-394 ◽  
Author(s):  
Antoinette Y. Odendaal ◽  
Narendra S. Deshmukh ◽  
Tennille K. Marx ◽  
Alexander G. Schauss ◽  
John R. Endres ◽  
...  

This toxicological assessment evaluated the safety of a hydroethanolic extract prepared from Caralluma fimbriata (CFE), a dietary supplement marketed worldwide as an appetite suppressant. Studies included 2 in vitro genotoxicity assays, a repeated dose oral toxicity study, and a developmental study in rats. No evidence of in vitro mutagenicity or clastogenicity surfaced in the in vitro studies at concentrations up to 5000 μg of extract/plate (Ames test) or 5000 μg of extract/mL (chromosomal aberration test). No deaths or treatment-related toxicity were seen in the 6-month chronic oral toxicity study in Sprague-Dawley rats conducted at 3 doses (100, 300, and 1000 mg/kg body weight (bw)/d). The no observed effect level for CFE in this study was considered to be 1000 mg/kg bw/d. A prenatal developmental toxicity study conducted at 3 doses (250, 500, and 1000 mg/kg bw/d) in female Sprague-Dawley rats resulted in no treatment-related external, visceral, or skeletal fetal abnormalities, and no treatment-related maternal or pregnancy alterations were seen at and up to the maximum dose tested. CFE was not associated with any toxicity or adverse events.


2001 ◽  
Vol 91 (4) ◽  
pp. 1828-1835 ◽  
Author(s):  
Nicole Stupka ◽  
Peter M. Tiidus

The effects of estrogen and ovariectomy on indexes of muscle damage after 2 h of complete hindlimb ischemia and 2 h of reperfusion were investigated in female Sprague-Dawley rats. The rats were assigned to one of three experimental groups: ovariectomized with a 17β-estradiol pellet implant (OE), ovariectomized with a placebo pellet implant (OP), or control with intact ovaries (R). It was hypothesized that following ischemia-reperfusion (I/R), muscle damage indexes [serum creatine kinase (CK) activity, calpain-like activity, inflammatory cell infiltration, and markers of lipid peroxidation (thiobarbituric-reactive substances)] would be lower in the OE and R rats compared with the OP rats due to the protective effects of estrogen. Serum CK activity following I/R was greater ( P < 0.01) in the R rats vs. OP rats and similar in the OP and OE rats. Calpain-like activity was greatest in the R rats ( P < 0.01) and similar in the OP and OE rats. Neutrophil infiltration was assessed using the myeloperoxidase (MPO) assay and immunohistochemical staining for CD43-positive (CD43+) cells. MPO activity was lower ( P < 0.05) in the OE rats compared with any other group and similar in the OP and R rats. The number of CD43+ cells was greater ( P < 0.01) in the OP rats compared with the OE and R rats and similar in the OE and R rats. The OE rats had lower ( P < 0.05) thiobarbituric-reactive substance content following I/R compared with the R and OP rats. Indexes of muscle damage were consistently attenuated in the OE rats but not in the R rats. A 10-fold difference in serum estrogen content may mediate this. Surprisingly, serum CK activity and muscle calpain-like activity were lower ( P< 0.05) in the OP rats compared with the R rats. Increases in serum insulin-like growth factor-1 content ( P < 0.05) due to ovariectomy were hypothesized to account for this finding. Thus both ovariectomy and estrogen supplementation have differential effects on indexes of I/R muscle damage.


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