Abstract
Introduction
Local anaesthetic has been reported to have a potentially detrimental effect on human chondrocytes both in vitro and in vivo. Due to chondroproliferative effects, magnesium may be an alternative intra-articular analgesic agent following arthroscopy. We aimed to examine the dose response effect of commonly used local anaesthetics on chondrocyte viability and also to report on the effect of adding magnesium to the local anesthetic agent.
Methods
Human chondrocytes were grown under standard culture conditions. Cells were exposed to either lignocaine (0.5, 1, 2%), levobupivacaine (0.125, 0.25, 0.5%), bupivacaine (0.125, 0.25, 0.5%) or ropivacaine (0.1875, 0.375, 0.75%) for 15 minutes. Cells were also exposed to a local anesthetic agent with the addition of magnesium (10, 20, or 50%). Cells exposed to culture media or saline served as controls. The MTS assay was used to assess cell viability 24 hours after exposure. One-way ANOVA were used to test for statistical significance.
Results
One-way ANOVA showed a dose response in all local anesthetic groups with the exception of lignocaine with higher concentrations leading to lower levels of cell viability. Magnesium alone was no more toxic than normal saline (P>0.3) compared to untreated cells. 50% magnesium showed similar effect on cell viability to the least toxic local anesthetic (lignocaine 1%, P=0.31). The addition of magnesium to the local anesthetic agents resulted in greater cell viability than when cells were treated with the respective local anaesthetic alone (lignocaine (P=0.033), levobupivacaine (P=0.007), bupivacaine (P<0.001), ropivacaine (P<0.001)).
Conclusion
We have showed that cell viability is improved with the addition of magnesium to local anaesthetic compared to the local anesthetic agent alone. We believe that these findings offer support to an alternative intra-articular analgesia following arthroscopy. However, the optimum doses and combinations of local anaesthetic and magnesium are yet to be shown.
