Effects of general anesthesia on airway immune cell function in an equine in vivo model.

The study investigates how general anesthesia affects the function of immune cells in the airway, using an in-vivo equine model. The research aims to understand how such changes might contribute to post-anesthetic complications such as pneumonia and decreased wound healing.

Research Objectives and Hypothesis

• The research was undertaken to explore the changes in airway immune cell function before and after an episode of general anesthesia. The hypothesis was based on the assumption that the performance of immune cells would be decreased in the post-anesthetic period.

Methodology

• The study had a prospective experimental design involving six adult horses owned by the institution.
• The research involved a bronchoalveolar lavage (BAL) on each horse three days before, and instantly after, a two-hour general anesthetic. BAL involves washing out of the bronchial and lung spaces to collect cells for examination – in this case, the immune cells.
• The fluid collected from BAL was analyzed for cytology, total nucleated cell count, and isolation of immune cells.
• These immune cells were then treated with Lipopolysaccharide (LPS) or a control media for six hours.
• The supernatant, or the fluid after removing the cells, was then analyzed for specific cytokines including tumor necrosis factor alpha (TNFα), interleukin (IL)-1β, IL-6, interferon gamma (IFNγ), and CXC motif chemokine ligand 8 (CXCL8).
• The data was then assessed and compared using t-tests and Mann-Whitney tests.

Key Findings

• Prior to anesthesia, LPS stimulation led to a significant increase in all cytokines of interest, excluding CXCL8, when compared to control samples.
• Following the anesthesia, cells that were unstimulated showed a significant 1.8-fold increase in IL-1β, and a significant decrease in IL-6 and TNFα, when compared to the baseline values.
• Stimulated cells, post-anesthesia, revealed a significant decrease in IL-6 and TNFα compared to the baseline.

Conclusion

• The findings of the study support the use of an equine in-vivo model to study airway immune cell function in relation to the use of general anesthetics.
• This could help to understand and address the immune-related complications that occur post-anesthesia, such as pneumonia and decreased wound healing.