Cellular content of secretions obtained by lavage from different levels of the equine respiratory tract.

This research focuses on the composition of cell types in respiratory secretions from different regions of the horse’s respiratory system, obtained through lavage – a rinse-based sampling method. It was found that the cell count and type varied with the tracts’ location, potentially due to varying exposure levels to airborne contaminants, individual interpretation of cellular types, and differences in lavage collection techniques.

Collection Methods and Findings

• The research team used lavage procedures – a rinse-based sampling technique – to collect secretions from the nasal cavity, trachea, bronchi, and bronchoalveolar level of healthy horses.
• It was reported that a progressive increase in total cell count was observed from the upper to the lower respiratory tracts.
• The primary constituents of nasal lavage fluid were epithelial cells, whereas the lavage fluids from the trachea, bronchi, and bronchoalveolar level contained higher numbers of macrophages, lymphocytes, and neutrophils.
• Further, eosinophils and mast cells were present in small numbers across all levels of the respiratory tract.

Comparative Analysis and Implications

• The differential cell counts derived from this study were compared with previously published reports. Significant differences were observed in the cellular compositions.
• These differences were hypothesized to be due to variations in collection technique, cytological interpretation of different cell types, and the presence of subclinical airway disease which could affect the cell composition and counts.
• The level of exposure to airborne environmental contaminants, which fluctuates depending upon the location of the respiratory tract, also likely influences the cellular content of respiratory lavage fluids.

Summary

• This study contributes to a deeper understanding of the cellular composition in various parts of a horse’s respiratory tract, shedding light on the pathophysiology of equine respiratory diseases.
• The observed variations in cell types across the respiratory tract and between different studies highlight the influence of collection techniques, individual interpretation of cell types, presence of subclinical diseases, and exposure to airborne contaminants.
• These insights can aid in the development of more standardized and effective lavage procedures for diagnosing respiratory disorders in horses.