Vascular abnormalities of the distal deep digital flexor tendon in 8 draught horses identified on histological examination.

This research investigates the changes in blood vessels within a specific part of the horse’s leg, deep digital flexor tendon, utilizing samples from eight horses that were diagnosed with tendinopathy, a condition affecting their tendons. The study finds that these changes, including the increase in number and size of blood vessels, can damage the structure of the tendon, leading to degenerative lesions.

Study Objective and Methodology

• The aim of this study was to explore the vascular alterations in the distal deep digital flexor tendon (DDFT), a critical part of a horse’s leg, using samples from eight horses diagnosed with DDF tendinopathy.
• The samples were collected post-mortem from the respective horses’ forelimbs and were subjected to ultrasound and anatomopathological evaluations to confirm the tendinopathy.
• These samples were then treated with 10% neutral buffered formalin for preservation, softened using 4% phenol and then dehydrated with alcohol.
• The study utilized the Goldner’s Trichrome staining method to aid in the subsequent histopathological investigation.

Study Findings

• The investigation revealed that there was an increase (proliferation) in the number of blood vessels (vascular proliferation) associated with structural problems within these vessels.
• Angiogenesis, the formation of new blood vessels, along with the increase in fibrous tissue (fibroplasia) and the corresponding enlargement (hypertrophy) of the vascular wall, with or without the blockage of these vessels (vascular occlusion), were common findings within the samples.
• The other histopathological findings included swelling of the endothelial cells (the cells lining the blood vessels), a change from squamous to cubic cells (progressive metaplasia), the build-up of a glass-like, translucent substance in the vascular wall (hyalinization), cell death (apoptosis/necrosis) of the endothelial cells, and the peeling off of these endothelial cells (desquamation).
• The study concludes that these observed changes suggest damage to the vascular structure of the distal deep digital flexor tendon, which could, over time, impact the structural integrity of the tendon, contributing to the development of degenerative conditions.