Assessment of apoptosis in epidermal lamellar cells in clinically normal horses and those with laminitis.

The research investigates and compares the occurrence and details of cell death (apoptosis) in the skin tissues of healthy horses and horses afflicted with laminitis. The findings suggest a significant role of cell death in the development of acute laminitis in horses.

Research Methodology

• The researchers examined tissue samples from the hooves of 47 horses. This sample included seven clinically normal horses, which served as controls, while the rest were experiencing different forms and stages of laminitis. Laminitis represents inflammation in the laminae tissues between the hoof and bone in horses.
• The tissues were prepared by formalin-fixing and paraffin-embedding and then stained using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) technique. The TUNEL technique is used to identify apoptotic cells, which are undergoing programmed cell death, by highlighting fragmented DNA regions.
• For secondary confirmation of apoptosis, differential immunohistochemical staining for proteins known as caspases 3 and 14 was used.

Results and Conclusions

• The researchers found a significantly greater number of TUNEL-positive cells (indicating apoptosis) in horses with acute stage laminitis compared to other groups. More specifically, the basal layer cells and keratinocytes showed higher levels of apoptosis.
• Within the group of horses with acute laminitis, the number of TUNEL-positive basal cells and keratinocytes was estimated to be 17 and 1,025 times more, respectively, than in the control group.
• Further, the apoptosis of TUNEL-positive basal cells was substantiated by the positive caspase 3 immunohistochemical staining.
• However, the TUNEL-positive keratinocytes did not exhibit staining for caspase 3 or 14, which could suggest a different mechanism of cell death in these cells.
• The concluding remarks of the study highlight the potential importance of apoptosis, specifically in the basal layer cells, in the onset and development of acute laminitis in horses. However, the exact role of the significantly large number of apoptotic keratinocytes remains unclear and warrants further investigation.