The protective effect of dexmedetomidine on bupivacaine-induced sciatic nerve inflammation is mediated by mast cells.

PURPOSE: This study was designed to assess the correlation between the neuroprotective effect of dexmedetomidine and oxidative stress, neural inflammation and mast cell stability in rats with bupivacaine-induced sciatic nerve toxicity.

METHODS

Forty adult Wistar Albino rats, eight rats per group, were used. Saline (0.3 ml of 0.9%), dexmedetomidine (20 µg/kg), 0.5% bupivacaine or 0.5% bupivacaine+dexmedetomidine (20 µg/kg) was injected into the sciatic nerve. A control group of rats received no injection. Fourteen days after injection, the sciatic nerves were harvested and total oxidant status, total anti-oxidant status, paraoxonase-1, galectin-3 and matrix metalloproteinase 2 and 9 levels were measured in the sciatic nerves. In addition, the presence and status of inflammation, edema, and mast cells were evaluated histopathologically.

RESULTS

The combination of dexmedetomidine and bupivacaine alleviated oxidative stress. In addition, it decreased matrix metalloproteinase 9 and galectin-3 levels and increased matrix metalloproteinase 2 levels. Moreover, it stabilized recruited mast cells at the injury site; however, it did not significantly decrease inflammation or edema.

CONCLUSION

Dexmedetomidine may ameliorate bupivacaine-induced neurotoxicity by modulating mast cell degranulation. The neuroprotective effect of dexmedetomidine may make it a suitable adjuvant agent to local anesthetics in peripheral nerve blocks.