Serial injections of 4% polyacrylamide hydrogel have no detrimental effects in equine joints following clinical, histologic, and synovial biomarker evaluation.

This research conducted a study to understand the impact of multiple doses of 4% polyacrylamide hydrogel (PAHG) – a supplement used to manage osteoarthritis in horses – on the animals’ joint health. The study found no significant harmful effects on the horses’ joints following serial injections of the compound.

Research Objectives and Methods

• The purpose of this study was to investigate the effects of repeated doses of 4% PAHG on the joint health of horses, looking specifically at clinical, histologic, and synovial fluid biomarker effects.
• The study involved eight healthy horses that were part of a blinded, controlled study. This means that those conducting the experiment did not know which horses were receiving the treatment and which were getting a control substance.
• The horses received either the 4% PAHG treatment or a 0.9% saline solution control periodically over a span of 135 days. The health of their joints was then evaluated on day 240.
• Samples of synovial fluid – the fluid that lubricates joints – were collected before the treatment and after the end of the study to assess cellular and biomarker changes.
• The researchers also performed physical and lameness examinations throughout the research period.

Research Findings

• The research found no significant changes in the histology of articular cartilage or synovial fluid biomarkers. This indicates that the presence of PAHG did not cause histologic abnormalities, or alter the cellular or biomarker composition of the horses’ synovial fluid, which could indicate damage or disease.
• A minor finding was that 4% PAHG was present on the surface of the synovial membrane in 5 out of 8 treated joints more than 100 days after the last treatment, which was considered an insignificant effect.
• The researchers concluded that multiple doses of the PAHG supplement administered at intervals over several months had minimal effects on the joints.

Conclusions and Implications

• The study concludes that regular administration of 4% PAHG injections in horses may safely provide long-term joint lubrication without harmful effects.
• This finding has potential clinical implications for osteoarthritis management in horses, providing reassurance that multiple doses of this supplement can be used over time without causing damage to the joints.