Evaluation of cytokine production by equine alveolar macrophages exposed to lipopolysaccharide, Aspergillus fumigatus, and a suspension of hay dust.

The research paper discusses a study that aimed to understand the production of certain immune response proteins in horse lung cells when exposed to various substances, including bacteria, fungus, and hay dust. Part of the research also evaluated the effect of a drug, clenbuterol, on this immune response.

Methods

• The experiment involved six horses, using their lung cells known as Alveolar Macrophages.
• These cells were exposed to various substances including a bacteria component called Lipopolysaccharide (LPS), a common fungus in horse environment Aspergillus fumigatus (AF), and Hay Dust Suspension (HDS).
• The cells were also exposed to a solution called PBS as a negative control, meaning this is what the cells behave like when they are not exposed to any special stimulus.
• After exposure, the cells were incubated for 24 hours at a temperature of 37 degrees Celsius.
• The amount of two immune response proteins, Tumor Necrosis Factor (TNF)-alpha and Interleukin (IL)-1beta, were then measured in the incubation solution.
• The entire process was then repeated, with the addition of the drug clenbuterol into the mix.

Results

• The researchers found that when exposed to HDS and AF, the horse lung cells produced significantly more TNF-alpha.
• Compared to LPS, HDS and AF caused the cells to produce five to seven times more TNF-alpha.
• The production of the other immune response protein, IL-1beta, was significantly increased only when the cells were exposed to AF.
• The drug clenbuterol was found to be effective in reducing the production of TNF-alpha, regardless of whether the cells were exposed to LPS, HDS, or AF.

Conclusions

• From their findings, the researchers theorized that the overproduction of these immune response proteins due to the exposure to common horse environment substances may contribute to a common horse lung condition called Recurrent Airway Obstruction (RAO).
• This suggests that the lung cells not only defend the horse against environment pollutants but also contribute to the development of the disease itself.
• The findings also suggest that clenbuterol, a drug often used to treat RAO, could potentially alleviate the condition by reducing the overreaction of the immune response.