Endotoxin-induced production of thromboxane and prostacyclin by equine peritoneal macrophages.
Abstract: Equine peritoneal macrophages were isolated and cultured in vitro to assess their ability to produce thromboxane (TxA2) and prostacyclin (PGI2) in response to endotoxin. Peritoneal macrophages (2.5 x 10(6)/ml) were incubated in tissue culture media, containing 1) no additive (nonstimulated control), 2) endotoxin (0.5 to 100 ng/ml) or 3) the calcium ionophore, A23187 (0.95 microM) for two and six h. Concentrations of the stable metabolites of TxA2 and PGI2 thromboxane B2 (TxB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), in the incubation media were determined by radioimmunoassay. The concentrations of both metabolites increased from two to six h incubation. Endotoxin increased the production of TxA2 and PGI2 over the nonstimulated control values at both two and six h and endotoxin-induced concentrations of 6-keto-PGF1 alpha were higher at six than at two h. The response of macrophages to A23187 was similar to endotoxin. Mean eicosanoid concentrations did not differ among the range of endotoxin concentrations at either time; however there was significant curvilinear regression between endotoxin concentration and TxB2 at both times, and between endotoxin and 6-keto-PGF1 alpha at two h. The results indicate that equine macrophages may be a significant source of TxA2 and PGI2 during endotoxemia.
Publication Date: 1987-01-01 PubMed ID: 3121207
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study investigates how horse peritoneal macrophages (a type of immune cell) in a lab setting respond to endotoxins (harmful substances released by bacteria) by producing thromboxane and prostacyclin, two compounds involved in blood clotting and inflammation.
Research Methodology
- Peritoneal macrophages were taken from horses and cultured in a lab for the experiment. The cells were suspended in a tissue culture medium (a nutrient solution for cell growth).
- Each set of macrophages was treated differently: one with no additives (control group), one with varying concentrations (0.5 to 100 ng/ml) of endotoxin, and one with a calcium ionophore called A23187 (0.95 microM).
- The cells were incubated for two intervals, two hours and six hours, after which the amount of the stable metabolites of thromboxane (TxB2) and prostacyclin (6-keto-PGF1 alpha) in the cultured medium was measured using a radioimmunoassay (a technique to measure substances in the body using radioactivity).
Key Findings
- The amount of both metabolites increased in the culture medium from two to six hours of incubation, implying that the macrophages were producing more TxB2 and PGI2 over time.
- The endotoxin and the calcium ionophore both stimulated the production of the metabolites, with the effect being stronger at the six-hour mark for the endotoxin group.
- The actual amount of endotoxin didn’t significantly alter the metabolite levels, but there was a notable curvilinear regression (a form of statistical relationship wherein increase or decrease in one variable doesn’t lead to a corresponding linear increase or decrease in another variable) between endotoxin concentration and TxB2 at both time intervals and between endotoxin and 6-keto-PGF1 alpha at two hours.
Conclusion and implications
- This study suggests that in conditions of endotoxemia (presence of endotoxins in blood), equine peritoneal macrophages could be a significant source of thromboxane and prostacyclin. These chemicals are known to be involved in bodily processes such as inflammation and blood clotting, making their increased production potentially relevant to how a horse’s body reacts to bacterial infections.
Cite This Article
APA
Morris DD, Moore JN.
(1987).
Endotoxin-induced production of thromboxane and prostacyclin by equine peritoneal macrophages.
Circ Shock, 23(4), 295-303.
Publication
Researcher Affiliations
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602.
MeSH Terms
- 6-Ketoprostaglandin F1 alpha / biosynthesis
- Animals
- Calcimycin / pharmacology
- Endotoxins / pharmacology
- Epoprostenol / biosynthesis
- Female
- Horses / metabolism
- In Vitro Techniques
- Macrophages / metabolism
- Male
- Peritoneal Cavity / cytology
- Thromboxane A2 / biosynthesis
Citations
This article has been cited 2 times.- Conway EA, Evans NP, Ridyard AE. Urinary 11-dehydrothromboxane B(2) concentrations in 20 dogs with primary immune-mediated hemolytic anemia.. J Vet Intern Med 2022 Jan;36(1):86-96.
- Morris DD, Crowe N, Moore JN. Reduced endotoxin-induced production of tumor necrosis factor activity by equine peritoneal macrophages exposed to the dual inhibitor of arachidonic acid metabolism, SK & F 86002.. Can J Vet Res 1992 Apr;56(2):110-4.
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