In vivo effects of a single intra-articular injection of 2% lidocaine or 0.5% bupivacaine on articular cartilage of normal horses.

The research investigates the impact of intra-articular injections of lidocaine or bupivacaine on biomarkers of cartilage metabolism. The study finds that these anaesthetics cause an increase in markers representing cartilage matrix synthesis, thus suggesting a possible anabolic effect.

Study Design and Methods

• The study was conducted using 6 healthy horses.
• The experiment had two parts; the first examined the effects of 0.5% intra-articular (IA) bupivacaine in the intercarpal joints.
• After a two-week washout duration, the second part analyzed the impact of 2% IA lidocaine in the tarsocrural joints.
• Horses were assigned randomly to either receive the test local anesthetic in the target joint or the placebo (0.9% NaCl) in the contralateral joint.
• Post the initial two-week washout period, the treatments were reversed, making sure each treatment was tested on 6 joints.
• Synovial fluid (SF) samples were taken for measuring biomarkers of carticulture metabolism.

Results

• Both lidocaine and bupivacaine showed a significant escalation in cartilage matrix synthesis markers – CS846-aggrecan and CPII-type II collagen – suggesting a potential restorative or anabolic effect.
• Bupivacaine also displayed an unexpected decrease in collagen degradation biomarkers – C2C and C1,2C.

Conclusion

• The study indicates an anabolic effect of a single intra-articular injection of the local anesthetics on cartilage metabolism.
• Though collagen degradation biomarker results did not increase, researchers posit that the anabolic response could still be due to an unobserved cartilage damage, which mandates further research.