Search Results

You are looking at 41 - 50 of 193 items for :

  • Refine by Access: All Content x
Clear All

Abstract

Objective—To determine the effects of interleukin- 1β (IL-1β) and tumor necrosis factor-α (TNF-α) on expression and regulation of several matrix-related genes by equine articular chondrocytes.

Sample Population—Articular cartilage harvested from grossly normal joints of 8 foals, 6 yearling horses, and 8 adult horses.

Procedure—Chondrocytes maintained in suspension cultures were treated with various doses of human recombinant IL-1β or TNF-α. Northern blots of total RNA from untreated and treated chondrocytes were probed with equine complementary DNA (cDNA) probes for cartilage matrix-related genes. Incorporation of 35S-sulfate, fluorography of 14C-proline labeled medium, zymography, and western blotting were used to confirm effects on protein synthesis.

Results—IL-1β and TNF-α increased steady-state amounts of mRNA of matrix metalloproteinases 1, 3, and 13 by up to 100-fold. Amount of mRNA of tissue inhibitor of metalloproteinase-1 also increased but to a lesser extent (1.5- to 2-fold). Amounts of mRNA of type-II collagen and link protein were consistently decreased in a dose-dependent manner. Amount of aggrecan mRNA was decreased slightly; amounts of biglycan and decorin mRNA were minimally affected.

Conclusions and Clinical Relevance—Treatment of cultured equine chondrocytes with IL-1β or TNF-α resulted in marked alterations in expression of various matrix and matrix-related genes consistent with the implicated involvement of these genes in arthritis. Expression of matrix metalloproteinases was increased far more than expression of their putative endogenous inhibitor. Results support the suggestion that IL-1β and TNF-α play a role in the degradation of articular cartilage in arthritis. (Am J Vet Res 2000;61: 624–630)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate cytokine production by equine alveolar macrophages after exposure to lipopolysaccharide (LPS), Aspergillus fumigatus, and hay dust, and determine the effect of clenbuterol on the cytokine response.

Animals—6 horses.

Procedures—Alveolar macrophages were exposed to PBS solution (negative control), LPS, hyphae and conidia of Aspergillus fumigatus (AF), or a suspension of hay dust (HDS) and incubated for 24 hours at 37°C. Concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-1β were measured in the supernatant. The procedure was repeated with cells that were concurrently incubated with 0.5µM clenbuterol.

Results—Exposure to HDS and AF significantly increased production of TNF-α by equine alveolar macrophages. The increase in TNF-α produced in response to HDS and AF was 5 and 7 times as great, respectively, as the increase measured in response to LPS. The concentration of IL-1β in the supernatant was significantly increased after exposure of cells to AF. Clenbuterol was effective at inhibiting TNF-α production by cells exposed to LPS, HDS, or AF.

Conclusions and Clinical Relevance—Increased production of TNF-α and IL-1 indicated that the proinflammatory cytokines produced by alveolar macrophages in response to allergens may play a role in recurrent airway obstruction (RAO) in horses. Equine alveolar macrophages are not only a primary pulmonary defense mechanism but may also influence the pathogenesis of equine RAO. The β2-adrenoceptor agonist clenbuterol, a drug that is commonly used for treatment of equine RAO, promotes immediate bronchodilation and may also contribute to downward modulation of the inflammatory response. (Am J Vet Res 2005;66:1584–1589)

Full access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate effects of thermal environment on response to acute peripheral lipopolysaccharide (LPS) challenge exposure in neonatal pigs.

Animals

26 neonatal pigs.

Procedure

Pigs were assigned to the following treatment groups: 1 warm environment/LPS; 2 warm environment/saline solution; 3 cool environment/LPS; and 4 cool environment/saline solution. For each pig given LPS. 1 littermate of the same sex was given saline solution. Sows with baby pigs were housed in a warm (32 C) or cool (21 C) thermal environment. At 28 days of age, pigs were given 150 µg/kg of body weight of Escherichia coli LPS or saline solution intraperitoneally as a control. Rectal temperature and signs of sickness were monitored for 3 hours after LPS administration, when pigs were euthanatized and blood samples were collected to determine serum concentrations of tumor necrosis factor (TNF) α and cortisol. To determine in vitro production of TNFα, alveolar macrophages were collected by tracheal lavage and incubated for 24 hours at 37 or 41 C, with or without LPS (10 µg/ml).

Results

Thermal environment had a significant (P = 0.0004) effect on rectal temperature; LPS administration induced a febrile response (P = 0.0007) only in pigs in the warm environment. All LPS-injected pigs developed signs of endotoxemia; serum TNFα and cortisol concentrations were significantly increased (TNFα, P = 0.003; cortisol, P = 0.0001); there was no significant in vivo thermal effect on serum TNFα and cortisol concentrations. LPS-stimulated alveolar macrophages produced significantly less (P = 0.0086) TNFα when incubated at 41 C.

Conclusions

Thermal environment can have a significant impact on the response of neonatal pigs exposed to bacterial endotoxins. (Am J Vet Res 1997; 58:364-369)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether small intestinal ischemia and reperfusion induces bacterial translocation and proinflammatory cytokine response in either the systemic or portal circulation in dogs.

Animals—17 healthy adult Beagles.

Procedure—The superior mesenteric artery (SMA) was occluded for 0 (group-3 dogs), 30 (group-1 dogs), or 60 (group-2 dogs) minutes, followed by reperfusion for 180 minutes; serum lactate and endotoxin concentrations and tumor necrosis factor-α (TNF-α), interleukin- 1β (IL-1β), and IL-6 activities in the systemic and portal circulation and intramucosal pH were measured at various time points.

Results—In group-2 dogs, TNF-α activity was found to be significantly increased in the portal circulation, peaking at 60 minutes of reperfusion; TNF-α activity, in the systemic circulation, gradually increased from 60 minutes of reperfusion to the end of the experiment; however, the increase was not significant. In group-1 and -2 dogs, IL-6 activities significantly and gradually increased in the systemic and portal circulation during the reperfusion phase, and the magnitude of these increases was dependent on the duration of the ischemic phase. There were no significant changes in IL-1β activity or endotoxin concentration in any dog group.

Conclusions and Clinical Relevance—Results of the our study indicate that intestinal ischemia and reperfusion leads to significant increases of the circulating TNF-α and IL-6 activities, depending on the duration of the ischemia phase, in the absence of detectable endotoxin in the circulation. This finding suggests that intestinal ischemia and reperfusion induces a systemic proinflammatory cytokine response in dogs. (Am J Vet Res 2002;63:1680–1686)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether concentrations of proinflammatory cytokines, acute-phase proteins, and cortisol differ at parturition among 3 categories of sows (noninoculated, clinically affected and nonaffected following intramammary inoculation with Escherichia coli).

Animals—16 sows.

Procedure—Sows were allocated to inoculated (n = 12) or noninoculated (4) groups. Inoculated sows received intramammary administration of E coli (serotype O127) during the 24-hour period preceding parturition. Blood samples were collected from noninoculated and inoculated sows for 3 consecutive days within 3 to 11 days before farrowing and inoculation. Samples were also collected 0, 24, 48, 72, and 96 hours after farrowing and inoculation. Inoculated sows were further categorized as affected (4 sows) or nonaffected (8 sows) based on clinical signs of disease. Serum tumor necrosis factor (TNF)-α, plasma interleukin (IL)-6, and serum amyloid A (SAA) concentrations were measured by use of ELISA; serum haptoglobin concentration was assayed by use of a hemoglobin- binding method; and plasma cortisol concentration was determined by use of radioimmunoassay.

Results—Plasma or serum concentrations of TNF-α, IL-6, and SAA of both categories of inoculated sows were significantly increased by 24 hours after intramammary inoculation of E coli, compared with concentrations in noninoculated sows. Concentrations of serum TNF-α and plasma IL-6 were significantly higher in inoculated sows that developed clinical mastitis than in nonaffected inoculated sows.

Conclusions and Clinical Relevance—Concentrations of TNF-α and IL-6 are promising markers for the identification of periparturient sows with subclinical coliform mastitis. Identification of such sows should help improve the health and survival of piglets. (Am J Vet Res 2004;65:1434–1439)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of interleukin (IL)-1 and tumor necrosis factor (TNF)-α on canine chondrocytes cultured in an agarose-based 3-dimensional (3-D) system.

Sample Population—Humeral head articular cartilage chondrocytes obtained from 6 adult dogs.

Procedure—Chondrocytes were cultured in a 3-D system for ≤ 12 days in serum-free medium with IL-1α, IL-1β, or TNF-α at concentrations of 20, 50, or 100 ng/mL. After 1, 3, 6, and 12 days, glycosaminoglycan (GAG) concentrations in 3-D constructs; nitric oxide and prostaglandin E2 (PGE2) concentrations in media samples; and relative expressions of selected genes, including metalloproteinase (MMP)-13 and tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2, were evaluated. Control specimens were comprised of chondrocytes cultured without proinflammatory cytokines.

Results—In control 3-D constructs, GAG content was significantly higher than for all other constructs. Compared with control values, relative expressions of MMP-13, TIMP-1, and TIMP-2 genes in the IL-1β (50 ng/mL) group were significantly higher at day 1; at all evaluations, media concentrations of nitric oxide were significantly higher in all TNF-α–treated cultures; and concentrations of PGE2 in media samples were significantly higher in the IL-1β (50 ng/mL) and IL-1β (100 ng/mL) groups at days 1 and 3, in the IL-1β (100 ng/mL) group at day 6, and in all TNF-α groups at days 1, 3, and 6.

Conclusions and Clinical Relevance—Results suggested that TNF-α more readily induces production of nitric oxide and PGE2 by canine chondrocytes, compared with IL-1β. In vitro, IL-1α appeared to have a minimal effect on canine chondrocytes. (Am J Vet Res 2005;66:1187–1196)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To define the cytokine response of a cultured mammary gland epithelial cell line (ie, Mac-T) when incubated with Escherichia coli or its products.

Sample Population—Mac-T cells and E coli from cows with mastitis.

Procedure—Mac-T cells were incubated with E coli or its products. The cytokine response of Mac-T cells to these treatments was quantified by measuring mRNA content of interleukin (IL)-1α, IL-1β, IL-8, and tumor necrosis factor (TNF)-α by use of a quantitative reverse transcriptase-polymerase chain reaction assay. The amount of TNF-α secreted was also measured.

Results—Treatment with E coli or its products resulted in significant increases in IL-1α, IL-8, and TNF-α mRNA content in Mac-T cells. This increase was reversible when culture filtrate was incubated with polymyxin B. The amount of IL-1β mRNA in Mac-T cells increased only slightly over baseline after treatment with E coli or its products, but this increase was not diminished by incubation of E coli filtrate with polymyxin B.

Conclusions and Clinical Relevance—Incubation of Mac-T cells with E coli or its products resulted in increased amounts of IL-1α, IL-8, and TNF-α mRNA. Inhibition of this response by incubation of culture filtrate with polymyxin B suggested that lipopolysaccharide was the main bacterial product that stimulated the cytokine response. The small increase in IL-1β content in Mac-T cells incubated with E coli or its products suggested that this cytokine had a smaller role in the Mac-T cell response to E coli. (Am J Vet Res 2005;66:1590–1597)

Full access
in American Journal of Veterinary Research

Abstract

Objective

To determine whether differences exist in induction and quantity of tumor necrosis factor α (TNF-α), interleukin (IL)1ß, and IL-10 mRNA transcripts when mouse J774A.1 macrophages are infected with Listeria monocytogenes, including 2 isolates originating from channel catfish, the wild-type virulent (EGD) strain, and a nonhemolytic strain (ATCC 15313).

Samples

Listeria monocytogenes isolates from kidneys or fillets of channel catfish were used to stimulate cytokine production from mouse macrophages. The RNA from the infected macrophages was collected.

Procedure

Four hours after infection with L monocytogenes, total cellular RNA was extracted from the J774A.1 cells and reversed transcribed to cDNA, which was amplified, using specific primers for TNF- α, IL-1ß, or IL-10. The specific amplified DNA fragments were detected on polyacrylamide gels and quantified, using a reverse transcription polymerase chain reaction (PCR)-mediated ELISA.

Results

The wild-type hemolytic EGD strain and the 2 hemolytic catfish isolates of L monocytogenes induced higher amounts of TNF-α-, IL-1ß-, and IL-10- specific mRNA in J774A.1 cells than did the nonhemolytic strain.

Conclusions

Hemolysin-associated induction of TNF-α, IL-1ß, and IL-10 cytokines may be related to survival and replication of L monocytogenes in macrophages. It also suggests that the PCR-mediated ELISA procedure is a sensitive test to quantify cytokines from cell cultures. (Am J Vet Res 1998;59:717-721)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To develop a model to study the kinetics and relative amounts of cytokines produced by liver cells during enteric infection.

Design

Salmonella enteriditis lipopolysaccharide (LPS)-or live S choleraesuis-stimulated isolated livers from clinically normal pigs and pigs with active acute phase response.

Animals

7- to 14-day-old salmonellosis-free pigs, 4 to 12/group.

Procedure

Livers were removed and perfused with oxygenated Krebs-Henseleit solution for 30 minutes and with S choleraesuis or LPS added for 7 minutes. Livers were then perfused with 500 ml of fresh solution in a closed loop procedure for 180 minutes. Perfusate samples were collected for tumor necrosis factor-α (TNFα) and interleukin 6 (IL-6) bioassays.

Results

Tumor necrosis factor-α values remained constant during perfusion of normal livers and increased in those exposed to LPS. Interleukin 6 values increased in perfusate from normal livers from 30 to 150 minutes, then decreased. In livers from pigs with an active acute phase response, TNFα values were reduced; IL-6 appeared by 2 minutes and decreased after 25 minutes.

Conclusions

Isolated livers could be kept viable for 3 hours, and IL-6 and TNFα could be measured by the bioassays used.

Clinical Relevance

Model can be used for studying and modifying the response of liver cells to infective agents. (Am J Vet Res 1996;57:472–476)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To correlate gene transcription of cytokines and chemokines with histologic inflammation in nasal biopsy specimens of cats.

Animals—25 study cats and 4 specific pathogen–free cats.

Procedure—One nasal biopsy specimen from each cat was submitted for routine histologic evaluation; a second was submitted for evaluation by use of a quantitative real-time polymerase chain reaction analysis with a fluorogenic probe (ie, TaqMan) for detection of cytokines and chemokines (interleukin [IL]-4, IL-5, IL-6, IL-10, IL-12 p40, IL-16, IL-18, interferon [IFN]-γ, tumor necrosis factor [TNF]-α, and the regulated on activation normal T cell expressed and secreted [RANTES] protein). Specimens were grouped histologically by degree of inflammation (none, mild, moderate, or severe). Linearized TaqMan signals for each gene were compared among histologic groups.

Results—Nasal biopsy specimens from specific pathogen–free cats were histologically normal, and cytokine transcription was low in these samples. As nasal inflammation in study cats worsened from absent (n = 3) to mild (4) to moderate (8) or severe (10), progressively and significantly increasing transcription of IL-6, IL-10, IL-12 p40, IFN-γ, TNF-α, and the RANTES protein was detected. Transcription of IL-4, IL- 5, IL-16, and IL-18 did not correlate with worsened histologic inflammation.

Conclusions and Clinical Relevance—Transcription of specific cytokines and chemokines in nasal tissue of cats progressively increased with severity of histologic evidence of inflammation, and IL-6, IL-10, IL-12 p40, IFN-γ, TNF-α, and the RANTES protein were markers of inflammation. Our data suggest that the nasal cavity of cats is biased toward a Th1 cytokine profile that is augmented by inflammation. (Am J Vet Res 2005;66:996–1001)

Full access
in American Journal of Veterinary Research