Flow cytometric analysis of peripheral blood mononuclear cells induced by experimental endotoxemia in horse.

The research investigates the impacts of experimentally-induced endotoxemia on cellular activation and functional cell surface markers in horses. This is done by analyzing the flow cytometric analysis of infected horses’ peripheral blood mononuclear cells.

Research Methodology

• The experiment involved eight healthy adult horses, which were given a low dose of endotoxin derived from Escherichia coli. This dose was given intravenously and was equivalent to 30 nanograms per kilogram of the horse’s body weight.
• For control purposes, five additional horses were administered an equivalent volume of a sterile saline solution.
• The experiment included the collection of venous blood samples, which were then used for flow cytometric analysis of the horses’ peripheral blood mononuclear cells (PBMCs).
• Beyond the cellular analysis, the researchers also measured plasma endotoxin concentrations in the horses.
• The horses’ clinical signs of endotoxemia were recorded at various intervals, ranging from 10 minutes up to 48 hours after administration of either the endotoxin or the saline solution.

Key Research Findings

• All horses administered with endotoxin exhibited transient clinical signs of endotoxemia, including tachycardia, tachypnea, increased rectal temperature, and leukopenia. These symptoms emerge as a higher heart rate, faster breathing rate, raised body temperature, and reduced white blood cell count, respectively.
• Surprisingly, detectable plasma endotoxin concentrations were only present in 50% of the horses given endotoxin. This suggests that not all horses react identically to endotoxin exposure, possibly due to variations in their immune responses.
• Significant changes in the functional cell surface markers were noted post endotoxin infusion. Specifically, the percentage of CD4(+), CD5(+), and CD8(+) cells decreased, while CD14(+), IgM(+), and MHC class II(+) cells increased.

Conclusion

• The results indicate that experimentally-induced endotoxemia alters the immunophenotype of horses’ PBMCs. The shifts in immune cell populations and their associated markers were linked with changes in the horses’ vital signs, thereby indicating an alteration in the immuno balance.