Interaction of lidocaine with reactive oxygen and nitrogen species

Abstract

Background and objective To investigate the ability of lidocaine to inhibit reactive oxygen and/or nitrogen species generation by either human leukocytes or cell-free systems via luminol- and lucigenin-enhanced chemiluminescence.

Methods Venous blood was obtained from healthy volunteers and leukocytes were isolated, from which chemiluminescence was generated. Also, chemiluminescence, induced by H₂O₂, HOCl, peroxynitrite or ferrous iron, was generated in cell-free systems.

Results Lidocaine produced a concentration-dependent inhibition in chemiluminescence generated by leukocytes (92 ± 1%, 1 mM). In cell-free experiments, lidocaine (1 mM) markedly inhibited chemiluminescence of xanthine-xanthine oxidase (24 ± 3%), while it slightly suppressed hypochlorous acid-induced chemiluminescence (9 ± 2%). Peroxynitrite-induced luminol- and lucigenin-enhanced chemiluminescence were also inhibited by lidocaine at 1 mM (19 ± 3% and 48 ± 8%, respectively). Lidocaine did not affect chemiluminescence generated by FeSO₄. However, lidocaine produced a biphasic effect on H₂O₂-induced chemiluminescence (37 ± 5% inhibition at 0.01 mM and 61 ± 17% activation at 1 mM).

Conclusions Lidocaine can elicit direct scavenging activity at high concentrations that might be important at or near the site of injection in local anaesthetic use.