Differential scanning calorimetric studies of superficial digital flexor tendon degeneration in the horse.

The research attempts to study degeneration in a horse’s superficial digital flexor tendon using differential scanning calorimetry (DSC) and examines how the changes observed align with the degeneration process in the structure and function of the tendon, particularly collagen fibers.

Research Methods

• The researchers employed Differential scanning calorimetry (DSC) as a tool to study the breakdown in the superficial digital flexor tendons in horses. DSC measures the heat flow associated with physical and chemical transitions in material, in this case, the tendon tissue.
• The degenerated core of damaged tendons was specifically observed under DSC to grasp the extent of damage and understand the denaturation process.

Findings

• They discovered a small exothermic peak at 23 degrees Celsius of unknown origin and a large endothermic peak at 70 degrees Celsius indicating denaturation of cross-linked collagen fibers.
• The denaturation temperature remained constant at 70 degrees Celsius even in the damaged core of the tendons, yet the enthalpy (a measure of heat energy) decreased, corresponding to the degree of tendon degradation.
• The research suggests that the enthalpy reduction is attributable to depolymerisation and denaturation (breaking down) of collagen fibers, the principal structural protein in the tendon.
• The evidence supporting this claim is the increased activity of the enzyme cathepsin B, a degradative enzyme secreted by fibroblasts, cells that produce collagen and other fibers. This enzyme helps break down proteins and is active when tissue or cells are undergoing stress or death.
• DSC analyses of cultured porcine (pig) tendon fibroblasts exhibited a multicomponent endotherm (absorption of heat), with denaturation beginning at 46 degrees Celsius, a temperature which the tendons could reach during heavy exercise.

Conclusion

• This research concludes that DSC can be a significant tool along with morphological and biochemical studies to understand the causes and progress of equine tendon degeneration.