Local anesthetics impair human granulocyte phagocytosis activity, oxidative burst, and CD11b expression in response to Staphylococcus aureus.
BACKGROUND
With invasion of bacteria, the host defense system is activated by a complex cascade of various mechanisms. Local anesthetics previously were shown to interact with diverse components of the immune response, such as leukocyte adherence on endothelial monolayers, oxidative burst, or crosstalk within lymphocyte subset populations. However, effects of newer local anesthetics like bupivacaine and ropivacaine on antibacterial host defense-primarily phagocytosis activity, oxidative burst, or CD11b expression-still remain unclear.


METHODS
Whole blood samples were preincubated with local anesthetics (lidocaine, 9.2, 92.2, and 1,846 microm bupivacaine, 6.1, 61, and 770 microm; ropivacaine, 6.4, 64, and 801 microm). For the oxidative burst and CD11b assay, dihydroethidium was added to the probes. After viable Staphylococcus aureus was added in a 5 to 1 ratio following leukocyte count, phagocytosis was stopped at different times, and staining with monoclonal antibodies was performed for subsequent flow cytometric analysis of phagocytosis activity, oxidative burst, and CD11b expression.


RESULTS
Granulocyte phagocytosis activity, CD11b expression, and generation of reactive oxygen species were significantly reduced by lidocaine (P < 0.0002) and bupivacaine (P < 0.005) in the highest concentration (1,846 microm and 770 microm, respectively). The capability of granulocytes to ingest bacteria was significantly depressed only by lidocaine (P < 0.003). Ropivacaine had no significant effect on any parameter investigated.


CONCLUSIONS
Local anesthetic dose and structure dependently inhibit inflammatory and immunologic parameters of granulocyte functions. Ropivacaine shows low interference with granulocyte immunologic and inflammatory functions.
Kiefer
Ralph-Thomas
RT
Department of Anesthesiology and Intensive Care Medicine, Eberhard-Karls University, Tuebingen, Germany. thomas.kiefer@uni-tuebingen.de
Ploppa
Annette
A
Krueger
Wolfgang A
WA
Plank
Michael
M
Nohé
Boris
B
Haeberle
Helene A
HA
Unertl
Klaus
K
Dieterich
Hans-Jürgen
HJ
D000328:Adult; D000577:Amides / Q000494:pharmacology; D000779:Anesthetics, Local / Q000494:pharmacology*; D002045:Bupivacaine / Q000494:pharmacology; D039481:CD11b Antigen / Q000096:biosynthesis*; D005260:Female; D005434:Flow Cytometry; D006098:Granulocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D010587:Phagocytosis / Q000187:drug effects*; D016897:Respiratory Burst / Q000187:drug effects*; D000077212:Ropivacaine; D013203:Staphylococcal Infections / Q000097:blood; D013211:Staphylococcus aureus / Q000276:immunology*
D000577:Amides; D000779:Anesthetics, Local; D039481:CD11b Antigen; D000077212:Ropivacaine; D008012:Lidocaine; D002045:Bupivacaine