Evaluation of diffusion of triamcinolone acetonide from the distal interphalangeal joint into the navicular bursa in horses.

The research article evaluates how the drug, triamcinolone acetonide, diffuses in horses from the distal interphalangeal joint (DIPJ) to the navicular bursa, and whether this diffusion is direct or systemic. It also checks if the addition of sodium hyaluronate affects the diffusion process.

Research Objective

• The main aim of the study was to investigate if triamcinolone acetonide, a steroid medication, diffuses from the distal interphalangeal joint (DIPJ) — a joint in the horse’s foot — to a sac filled with lubricating fluid in the hoof known as the navicular bursa.
• Another objective was to determine if this diffusion is direct (from the injection site directly to the navicular bursa) or systemic (through the bloodstream).
• The study also sought to find out whether the addition of sodium hyaluronan — a naturally occurring substance in the body that helps to lubricate and cushion joints — has any impact on the diffusion of triamcinolone acetonide.

Methodology

• The investigation involved 11 adult horses that did not have lameness in their forelimbs.
• In each horse, one randomly selected forelimb DIPJ was injected with a combination of 10 mg of triamcinolone acetonide and 20 mg of sodium hyaluronan (group 1).
• The opposing forelimb DIPJ was injected with 10 mg of triamcinolone acetonide plus 2 mL of a solution known as lactated Ringer’s (group 2).
• Synovial fluid samples were then collected from both the forelimb navicular bursae and one hind limb navicular bursa after six hours for analysis.
• The triamcinolone acetonide concentrations in the synovial fluid samples were quantified using a technique called high-performance liquid chromatography in conjunction with tandem mass spectrometry.

Results

• The analysis detected triamcinolone acetonide in navicular bursal samples from all groups. However, the concentrations of the drug were significantly higher in groups 1 and 2 compared to the systemic control group, indicating that the drug diffused directly from the DIPJ to the navicular bursa.
• There was no significant difference in drug concentration between groups 1 and 2. This means that the presence or absence of sodium hyaluronan did not influence diffusion of triamcinolone acetonide.

Conclusion

• The study concluded that triamcinolone acetonide diffused directly from the DIPJ into the navicular bursa in clinically normal horses, and this diffusion process was not impacted by the addition of hyaluronan.
• Due to this direct diffusion, the researchers suggested that an injection into the DIPJ with triamcinolone acetonide or a triamcinolone acetonide-hyaluronan combination could be potentially used for treating navicular syndrome. However, they also highlighted that further studies are necessary to determine if triamcinolone acetonide diffuses in a similar way in horses suffering from navicular syndrome.