leukotriene-b4 and Mastitis--Bovine

The staphylococcal bi-component leukotoxins constitute a family included in the super-family of the beta-sheet-structured pore-forming toxins. They may be produced by Staphylococcus aureus and by Staphylococcus intermedius and their target cells vary according to the molecules. The mode of action proceeds by the sequential binding of the class S proteins, then by that of the class F proteins at the surface of the membranes. Then, the activation of cellular calcium-channels precedes the pore formation which seems to be sensitive to several monovalent cations. The cell response is inflammatory and includes the neosynthesis as well as the secretion of leukotriene B4, interleukin -8, histamine. The injection of leukotoxins to rabbits generates cell chemotaxis , vasodilatation, and tissue necrosis. The association of the production of leukotoxins with clinical syndromes concerns several aspects of the pathology of S. aureus, and confers to these leukotoxins an important role of virulence factors.

Topics: Animals; Bacterial Proteins; Bacterial Toxins; Calcium Channels; Cations, Divalent; Cattle; Cell Membrane Permeability; Chemotaxis, Leukocyte; Cross Infection; Erythrocytes; Exotoxins; Female; Hemolysin Proteins; Histamine Release; Humans; Interleukin-8; Ion Transport; Leukocidins; Leukotriene B4; Male; Mastitis, Bovine; Models, Biological; Necrosis; Neutrophils; Rabbits; Staphylococcal Infections; Staphylococcus aureus; T-Lymphocytes; Vasodilation; Virulence; Vitreous Body

Bovine mastitis is one of the most prevalent and costly diseases in the dairy industry. Lipid mediators are signaling molecules which coordinately and intricately modulate inflammation. They are produced from polyunsaturated fatty acids (PUFAs) in the cellular membrane via several enzymes including cyclooxygenase (COX) and lipoxygenase (LOX). In the present study, we performed comprehensive analysis of lipid production in milk obtained from clinical or subclinical mastitic cows using liquid chromatography/mass spectrometry. We detected 26, 24, and 40 kinds of lipid constantly in healthy, subclinical, and clinical mastitic milk, respectively. In clinical mastitic milk, the amount of a major n-6 PUFA, arachidonic acid (AA), tended to increase, whereas amounts of major n-3 PUFAs, eicosapentaenoic acid and docosahexaenoic acid, tended to decrease. The amounts of several AA-derived lipids including COX-catalyzed prostaglandin (PG) D

Topics: Animals; Arachidonic Acid; Biomarkers; Cattle; Dinoprostone; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Female; Leukotriene B4; Lipoxygenase; Mastitis, Bovine; Milk; Prostaglandin D2; Prostaglandin-Endoperoxide Synthases

The aim of the study was to determine the effects of lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF), interleukin-1-alpha (IL-1α), and nitric oxide donor (NONOate) on both in vivo and in vitro secretion of prostaglandin (PG)E2, PGF2α, leukotriene (LT)B4, and LTC4 by the bovine mammary gland. In the first experiment, tissues isolated from the teat cavity and lactiferous sinus were treated in vitro with LPS (10 ng/mL), TNF (10 ng/mL), IL-1α (10 ng/mL), NONOate (10(-4) M), and the combination of TNF + IL-1α + NONOate for 4 or 8 h. PGE2 or PGF2α secretion was stimulated by all treatments (P < 0.05) excepting NONOate alone, which did not stimulate PGF2α secretion. Moreover, all factors increased LTB4 and LTC4 secretion (P < 0.05). In the second experiment, mastitis was experimentally mimicked in vivo by repeated (12 h apart) intramammary infusions (5 mL) of (1) sterile saline; (2) 250-μg LPS; (3) 1-μg/mL TNF; (4) 1-μg/mL IL-1α; (5) 12.8-μg/mL NONOate; and (6) TNF + IL-1α + NONOate into 2 udder quarters. All infused factors changed PGE2, 13,14-dihydro,15-keto-PGF2α, and LT concentrations in blood plasma collected from the caudal vena cava, the caudal superficial epigastric (milk) vein, the jugular vein, and the abdominal aorta (P < 0.05). In summary, LPS and other inflammatory mastitis mediators modulate PG and LT secretion by bovine mammary gland in both in vivo and in vitro studies.

Topics: Animals; Cattle; Cytokines; Dinoprost; Dinoprostone; Female; Interleukin-1alpha; Leukotriene B4; Leukotriene C4; Leukotrienes; Lipopolysaccharides; Mammary Glands, Animal; Mastitis, Bovine; Nitric Oxide; Nitric Oxide Donors; Prostaglandins; Tumor Necrosis Factor-alpha

The aims of this study were to determine the effects of lipopolysaccharides (LPS), tumor necrosis factor (TNF), interleukin 1 alpha (IL-1α), nitric oxide donor (NONOate), or the combination of TNF + IL-1α + NONOate on the following: (i) secretion of prostaglandin (PG)-F(2α), PGE(2), leukotriene (LT)-B(4), and LTC(4) by epithelial cells of the teat cavity and lactiferous sinus of bovine mammary gland; (ii) messenger RNA (mRNA) transcription of enzymes responsible for arachidonic acid (AA) metabolism (prostaglandin-endoperoxide synthase 2 [PTGS2], prostaglandin E synthase [PTGES], prostaglandin F synthase [PGFS], and arachidonate 5-lipooxygenase [ALOX5]); and (iii) proliferation of the cells. The cells were stimulated for 24 h. Prostaglandins and LT were measured by enzyme immunoassay, mRNA transcription of enzymes was determined by real-time reverse transcription polymerase chain reaction, and the cell viability was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide. All factors increased PG secretion, but the highest stimulation was observed after TNF and IL-1α (P < 0.001). Tumor necrosis factor, NONOate, and TNF + IL-1α + NONOate increased LTB(4) production (P < 0.01), whereas LTC(4) was increased by LPS, TNF, and IL-1α (P < 0.01). Lipopolysaccharides, TNF, IL-1α, and the reagents combination increased PTGS2, PTGES, and PGFS mRNA transcription (P < 0.01), whereas ALOX5 mRNA transcription was increased only by TNF (P < 0.001). Lipopolysaccharides, TNF, IL-1α, NONOate, and the combination of reagents increased the cell number (P < 0.001). Mediators of acute-clinical Escherichia coli mastitis locally modulate PG and LT secretion by the epithelial cells of the teat cavity and lactiferous sinus, which might be a useful first line of defense for the bovine mammary gland. Moreover, the modulation of PG and LT secretion and the changing ratio of luteotropic (PGE(2), LTB(4)) to luteolytic (PGF(2α), LTC(4)) metabolites may contribute to disorders in reproductive functions.

Topics: Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Cattle; Cell Proliferation; Cytokines; Dinoprost; Dinoprostone; Epithelial Cells; Female; Hydroxyprostaglandin Dehydrogenases; Interleukin-1alpha; Intramolecular Oxidoreductases; Leukotriene B4; Leukotriene C4; Leukotrienes; Lipopolysaccharides; Mammary Glands, Animal; Mastitis, Bovine; Nitric Oxide; Nitric Oxide Donors; Prostaglandin-E Synthases; Prostaglandin-Endoperoxide Synthases; Prostaglandins; RNA, Messenger; Tumor Necrosis Factor-alpha

Persistent accumulation of inflammatory cells in the udder, with neutrophils being the predominant cell type, is a characteristic feature of chronic mastitis in dairy cows. Leukotriene (LT) B4 is a potent chemotactic agent, known to induce recruitment and accumulation of neutrophils in the bovine mammary gland. The LTB4-stimulated neutrophil functional responses are closely opposed by lipoxin (LX) A4, which promotes the resolution of inflammation. We thus hypothesized that the chronic inflammation of the udder could be associated with an unfavorable ratio between these two eicosanoids and that the persistence of neutrophil accumulation could be due to an increase in LTB4 synthesis and/or an impaired LXA4 production. In an attempt to verify this hypothesis, we first measured LXA4, LTB4, and their ratio in the milk of healthy and acute and chronic mastitis-affected quarters. Next, we studied the relationships between these variables and the degree of udder inflammation as assessed by somatic cell count measurement. The LTB4 concentration was low in healthy quarters, drastically increased in acute mastitis, and reached intermediate levels in chronic mastitis-affected quarters. However, whereas LXA4 concentration was highly increased in acute mastitis, healthy and chronic quarters had similarly low values. The LXA4:LTB4 ratio was thus significantly lower in chronic mastitis-affected cows. The LTB4 concentrations measured in chronic quarters were highly correlated to somatic cell count and to milk neutrophil and macrophage numbers. A weaker correlation was observed between LXA4 and these variables. For both eicosanoids, the highest correlation was observed with the number of neutrophils. These results show the existence of an LXA4:LTB4 imbalance in chronic mastitis-affected cows because of low LXA4 concentrations. Further studies are needed to determine whether administration of LX or stable analogs could have therapeutic potential in the control of chronic bovine mastitis.

Topics: Acute Disease; Animals; Case-Control Studies; Cattle; Cell Count; Chronic Disease; Female; Leukotriene B4; Lipoxins; Macrophages; Mammary Glands, Animal; Mastitis, Bovine; Milk; Neutrophils

The relationships between nutrition and udder inflammation/infection were studied in the dairy cow using an ecopathological approach. The study ('enquête écopathologique Bretagne') was performed over 4 yr in French herds with high-lactating cows. A long distribution time of Italian ryegrass silage and a low quantity of dietary cereal-based concentrates in the first 2 months of lactation was linked with low milk leukocyte counts, probably due to a high dietary energetic level or to a polyunsaturated fatty acid imbalance and a subsequent decrease in the synthesis of leukotriene LTB4. In the late gestation period, a long distribution time of fresh English rye-grass, which induced high uraemia and a larger distribution of vitamins A, D and E, was related to lower frequencies of major pathogens in the milk.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Bacteria; Cattle; Energy Intake; Fatty Acids, Unsaturated; Female; Leukocyte Count; Leukotriene B4; Mastitis, Bovine; Milk; Vitamins

Migration of bovine neutrophils towards endotoxin, recombinant bovine interleukin-1 beta (rBoIL-1 beta), recombinant human tumor necrosis factor-alpha (rhTNF-alpha), platelet-activating factor (PAF), complement factor C5a, leukotriene B4 (LTB4), and recombinant human interleukin-8 (rhIL-8) was studied in vivo, using the teat cistern model, and in vitro using the modified Boyden chamber method. Infusion of endotoxin, rBoIL-1 beta, rhTNF-alpha, PAF, or C5a into the teat cistern induced significant accumulation of leukocytes, mainly neutrophils, during the sampling period. Endotoxin was, on a molar basis, the most potent inducer of cell accumulation in vivo, followed by rBoIL-1 beta, while C5a, PAF and rhTNF-alpha were less potent. No significant cell accumulation was observed after infusion of LTB4 or rhIL-8. A significant migration of cells into the teat cistern was first observed 2 h after the infusion of endotoxin or rBoIL-1 beta, the rBoIL-1 beta-induced response started somewhat earlier. The first significant cell accumulation after infusion of PAF or C5a was observed already 1.5 h post infusion. The largest numbers of cells were reached 2.5-4.5 h after the infusion of endotoxin, rBoIL-1 beta, rhTNF-alpha, PAF or C5a. In vitro, significant migration of bovine blood neutrophils was observed towards C5a or rhIL-8, and to a lower extent towards LTB4, while no chemotactic response to endotoxin, rBoIL-1 beta, rhTNF-alpha, and PAF was observed. Possible roles of the different substances as inducers of neutrophil migration into the bovine teat are discussed.

Topics: Animals; Bacterial Toxins; Cattle; Cell Movement; Chemotaxis, Leukocyte; Cytokines; Endotoxins; Female; Leukocyte Count; Leukotriene B4; Mammary Glands, Animal; Mastitis, Bovine; Neutrophils; Recombinant Proteins

The effect of combined administration of flunixin meglumine (FM) and nordihydroguaiaretic acid (NDGA) on milk prostaglandin F2 alpha (PGF2 alpha) and leukotriene B4 (LTB4) concentrations, and inflammatory indicators of bovine mastitis was examined. Mastitis was induced in six Holstein cows by the inoculation of Klebsiella pneumoniae via the teat canal. Four cows were intravenously treated with FM (1.1 mg/kg) and NDGA (10 mg/kg) 1 hour prior to bacterial inoculation and again at post inoculation hour (PIH) 11. Two control cows were intravenously treated with equivalent volume doses of sterile isotonic saline solution at the same post inoculation time points. Combined use of FM and NDGA was effective in reducing elevations in milk PGF2 alpha levels and slightly effective in reducing elevations in milk LTB4 levels in the mastitic cows. Elevations in milk bovine serum albumin (BSA) levels were partially reduced during the early post inoculation time period in the FM and NDGA treated cows as compared to the saline treated control cows. Milk somatic cell counts from inoculated quarters were not significantly altered by FM and NDGA treatment. Elevations in rectal temperature were not reduced by FM and NDGA treatment, but clinical signs of quarter inflammation (warmth and swelling) were reduced by FM and NDGA treatment.

Topics: Animals; Cattle; Clonixin; Dinoprost; Female; Klebsiella Infections; Klebsiella pneumoniae; Leukotriene B4; Masoprocol; Mastitis, Bovine

The effect of selenium deficiency on the product profile of arachidonic acid oxidation by enzymatic pathways in Holstein cows with experimentally-induced coliform mastitis was investigated. The animals were fed dairy rations containing 0.05 mg Se/kg dry matter, with the supplemented group receiving additional Se to increase the dietary concentration to approximately 0.35 mg Se/kg dry matter. Cows were inoculated intracisternally with 30 colony-forming-units of Escherichia coli at 14-16 weeks of lactation. Eicosanoids and bacteria numbers were recorded at various intervals of time for 60 h postinoculation. Milk from cows fed the Se-depleted diet had significantly higher (p less than 0.05) concentrations of TXB2 between 24 and 48 h and 6-keto-PGF1 alpha between 24 and 60 h postinoculation. Milk PGE2 concentration was significantly higher in the Se-deficient group at 24 h, whereas LTB4 was higher between 36 and 60 h postinoculation in the Se-deficient cows (p less than 0.05). Milk bacteria numbers were significantly higher between 16 and 24 h postinoculation in the Se-deficient group and three of the four cows in this group required euthanasia, whereas all four cows in the Se-supplemented group recovered without therapeutic intervention. These data indicate marked effects of dietary Se on milk eicosanoid concentrations in response to an E. coli infection. The changes in eicosanoid concentrations may be associated with the altered pathogenesis and outcome of mastitis in a Se-deficient state.

Topics: 6-Ketoprostaglandin F1 alpha; Administration, Oral; Animals; Cattle; Deficiency Diseases; Dinoprostone; Eicosanoids; Escherichia coli Infections; Leukotriene B4; Mastitis, Bovine; Milk; Selenium; Thromboxane B2; Time Factors; Treatment Outcome

Mastitis was induced in 4 lactating cows by inoculation of Klebsiella pneumoniae (10(7) organisms/ml) via the teat canal. Sterile isotonic saline solution (1 ml) was instilled into designated control quarters via the teat canal. Changes in milk leukotriene B4 and C4 (LTB4, LTC4) concentrations, milk somatic cell counts, and milk bovine serum albumin concentration were monitored over a 24-hour postinoculation period. Milk LTB4 concentration before inoculation in control quarters and quarters later to be infected was 376 +/- 45 and 326 +/- 56 pg/ml of milk, respectively. A significant (P less than 0.05) increase in milk LTB4 concentration in the infected quarters was first observed at postinoculation hour 6, and milk LTB4 concentration in infected quarters generally remained significantly high through postinoculation hour 14. Thereafter, milk LTB4 concentration in infected quarters was not significantly different from the concentration in control quarters. Measurable amounts of LTC4 were not detected in the milk of either control or infected quarters. Milk bovine serum albumin concentration in the infected quarters generally was high throughout the study, as were milk somatic cell counts. The results of this study suggested that LTB4 contributes to the pathogenesis of bovine mastitis.

Topics: Animals; Cattle; Cell Count; Female; Klebsiella Infections; Klebsiella pneumoniae; Leukotriene B4; Mastitis, Bovine; Milk; Serum Albumin, Bovine; SRS-A; Time Factors