Morphological and cellular changes in secondary epidermal laminae of horses with insulin-induced laminitis.

The study describes the cellular alternations in horses’ feet resulting from a condition called laminitis induced by insulin. The characteristics of the condition include elongation and narrowing of skin layers in all feet, attributed primarily to cell stretching and an accelerated process of cell death and regeneration.

Objective

To investigate the changes in skin layers and cells within the feet of ponies suffering from insulin-induced laminitis.

Design

• 8 ponies were used in the experiment. Laminitis was artificially induced in 4 of them using insulin and glucose. The remaining 4 were the control group and received saline solution.
• Tissue samples from the feet of all ponies were taken and analyzed histologically.
• Measurements of primary and secondary epidermal lamina (skin layers) and the number of epidermal cell nuclei per unit length were considered and compared.
• The number of cells that were undergoing apoptosis (cell death) and proliferation (cell multiplication) in different regions of the feet were also analyzed.

Results

• It was observed that in ponies with insulin-induced laminitis, the secondary epidermal lamina (SEL) were longer and narrower, and had a smaller angle compared to the primary epidermal lamina.
• The number of epidermal cell nuclei per SEL was typically higher in ponies with the condition.
• The number of cells per micrometer of SEL was lower in certain foot regions.
• It was also found that apoptotic cell numbers were higher in some foot regions both in forefeet and hind feet.
• Proliferating cell numbers were higher in specific regions in the feet, indicating an accelerated cell death-proliferation cycle.

Conclusion

• The study concluded that laminitis caused substantial modifications in the foot structure of ponies.
• These modifications included elongation, narrowing, and alteration in orientation of the skin layers, which is primarily attributable to cell stretching.
• The researchers believe the acceleration in cell death and proliferation could be a consequence of the condition.
• The disparity in cell cycle responses between front and rear feet may be due to differences in load bearing.