Effects of on-slide fixation on the cell quality of cytocentrifuged equine bronchioalveolar lavage fluid.

This study investigates how different methods of on-slide fixation impact the cell quality in bronchoalveolar lavage fluid (BALF) samples from horses. The research found that a wet-spray fixation method maintained optimal cell morphology, and was especially effective in preserving the sizes of macrophages, granulocytes, and mast cells better than air-drying techniques.

Research Methodology

• The research involved BALF samples from five horses. These samples were cytocentrifuged to concentrate the cells.
• Various methods were used for on-slide fixation. These include wet-spray fixation through a commercially available spray, acetone fixation, methanol fixation after air-drying the samples, and an unfixed, air-dried method.
• The samples were stored for varying durations and at different temperatures post fixation.
• Afterwards, these samples were stained with May-Grünwald Giemsa or other immunocytochemistry stains.
• The study assessed differential cell counts, measured cell areas and evaluated cell morphologies and immunocytochemical staining intensities semiquantitatively.

Research Findings

• Optimal cell morphology results were achieved with the wet-spray fixation method.
• Fixation with acetone and methanol, at a temperature of -20°C, was seen to decrease the quality of cell morphology, resulting in a significant alteration in the differential cell counts.
• When considering a storage period of a week at room temperature, no notable changes in cell morphology were observed irrespective of the fixation methods used.
• Wet-spray fixation was more effective in preserving the sizes of macrophages, granulocytes, and mast cells when compared with air-drying techniques.
• The immunocytochemical staining of unfixed and acetone-fixed samples were the most intense.

Conclusions

• The study concluded that wet-spray fixation yielded the best results in terms of preserving cellular morphology and reducing cell shrinkage relative to the use of unfixed specimens.
• The researchers thus recommend wet-spray fixation for processing BALF cytology.