Rapid, multiwell colorimetric assay for measuring neutrophil chemoattractant activity in bronchoalveolar lavage fluid of horses with recurrent airway obstruction.

This research article discusses a study on a rapid colorimetric assay to assess neutrophil chemoattractant activity in bronchoalveolar lavage fluid (BALF) of horses affected by recurrent airway obstruction (RAO). The study found that this assay can be a potential tool for RAO diagnosis and treatment monitoring, as neutrophil chemoattractant activity is significantly higher in RAO horses.

Objective of the Research

• The primary goal of this study is to determine if a previously described, rapid, multiwell colorimetric assay could potentially measure a neutrophil chemoattractant activity in bronchoalveolar lavage fluid (BALF) of horses affected by recurrent airway obstruction (RAO).

Methodology

• Fourteen adult horses, out of which seven had a history of RAO, were involved in the research. Each horse was sedated and had a bronchoalveolar lavage tube passed. Then, saline was infused and immediately aspirated.
• Two samples were then extracted from the BALF: an aliquot for differential cell count and a supernatant to evaluate neutrophil chemoattractant activity.
• In the colorimetric assay, neutrophils that migrated through a membrane filter were gathered into the bottom well of a disposable chemotaxis cell-migration chamber.
• The amount of live cells collected were quantified through the reduction measurement of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenol tetrazolium bromide (MTT). The reduction of MTT, a process completed by dehydrogenase in live cells’ mitochondria, correlates directly to the quantity of migrating cells.

Results and Findings

• Both RAO-affected and normal control horses were distinguished based on clinical manifestations and the percent of neutrophils in BALF.
• It was observed that the neutrophil chemoattractant activity in horse’s BALF was significantly greater in RAO-affected horses compared to the control ones (P = 0.001).

Conclusions and Implications

• The results suggest that this colorimetric assay might be helpful in future researches, potentially being applicable for monitoring therapy response in horses affected by RAO.
• This is vital as it could significantly improve diagnostic accuracy and could be a viable way to monitor the treatment response of horses affected by recurrent airway obstruction.