Mast cells in normal and pathological specimens of the equine lung.

The research paper investigates and compares the number and types of mast cells in healthy horse lungs with those from lungs with different histological lesions. The study identifies two sub-notions of mast cells, finds slight increases in mast cell numbers in mild chafing and moderate bronchitis cases, a significant increase around bronchioles in bronchiolitis and fibrosed pulmonary pleurae, and a striking increase in fibrosed alveolar septa.

Method of Investigation

• The study worked with a lung specimen from 22 horses. For better categorization, comparisons were made between mast cells in normal samples and those with various histological lesions.
• The researchers used two key fixation solutions, Carnoy’s Solution and Formalin, to test and identify the types of mast cells. The comparison aimed to discover the best solution for identifying mast cells. As a result, Carnoy’s solution was found superior to formalin for this purpose.

Classification of Mast Cells

• Based on the fixation techniques, two different subpopulations of mast cells were identified: formalin-sensitive and formalin-resistant mast cells. The formalin-sensitive mast cells were seen to be predominant.

Presence of Mast Cells in Different Conditions

• Specimens that showed signs of mild chronic tracheitis and mild or moderate chronic bronchitis generally exhibited mild increments in mast cell numbers compared to specimens with normal histology.
• Mast cell concentration increased around small and large bronchioles in cases of mild, moderate, and severe bronchiolitis. Similarly, in fibrosed pulmonary pleurae, mast cells were increased compared to specimens with no histological lesions.
• The most notable increase in mast cell count was observed in fibrosed alveolar septa, where the number was approximately four times as high compared to normal histological specimens.

Conclusion

• This study provides critical insights into the presence and prevalence of mast cells in horse lungs under different health and disease conditions. It presents a clear correlation between certain pathological conditions and an increase in mast cell count.