Effects of intraarticular corticosteroid and sodium hyaluronate injections on synovial fluid production and synovial fluid content of sodium hyaluronate and proteoglycans in normal equine joints.

The research study investigates the impact of different intra-articular injections on synovial fluid production and its contents such as sodium hyaluronate and proteoglycans in normal horse joints. It found that corticosteroid injections increase hyaluronate levels, suggesting these shots stimulate synoviocytes to produce more hyaluronate. Also, corticosteroids cause high levels of proteoglycans, implying joint cartilage degradation. However, combining corticosteroids and hyaluronate appears to reduce proteoglycan breakdown, suggesting a protective effect of hyaluronate on the joint cartilage.

Experiment Procedure

• The study involved administering repeated intra-articular injections containing beta-methasone, methylprednisolone, hyaluronate, saline, and combinations of beta-methasone + hyaluronate and methylprednisolone + hyaluronate in normal horse joints.
• This was done at the beginning of the study and after one and two weeks.
• Synovial samples were collected at the start of the study, and after 1, 2, 3, 4, 6, and 8 weeks.

Findings

• The study found no significant changes in the synovial volume after the repeated arthrocenteses and the experimental treatments.
• Corticosteroid injections increased levels of hyaluronate in the synovial fluid. This suggests a stimulatory effect on the synoviocytes to produce more hyaluronate.
• The corticosteroid injections also resulted in high levels (up to 20 times the initial level) of proteoglycans. This indicates joint cartilage degradation.
• However, a combined injection of corticosteroids and high molecular weight hyaluronate appeared to reduce proteoglycan breakdown. This suggests a protective effect of hyaluronate on the articular cartilage.

Implications

• The findings could influence the choice of treatment for joint conditions in equines, considering the effects of different compounds in intra-articular injections.
• Understanding the effects of corticosteroids on synoviocyte stimulation and proteoglycan levels might help in modulating treatments to control joint cartilage degradation.
• The protective role of hyaluronate in joint cartilage when combined with corticosteroids offers a potential way to mitigate the degrading effects of corticosteroids.