Bupivacaine causes cytotoxicity in mouse C2C12 myoblast cells: involvement of ERK and Akt signaling pathways.
OBJECTIVE
The adverse effects of local anesthetics (LAs) on wound healing at surgical sites have been suggested, and may be related to their cytotoxicity. This study was aimed to compare the cellular toxicity of bupivacaine and lidocaine (two well-known LAs), and to explore the molecular mechanism(s).


METHODS
Toxicity of bupivacaine and lidocaine was assessed in cultured mouse C2C12 myoblasts by cell viability and apoptosis assays. Effects of LAs on extracellular signal-regulated kinase (ERK) and protein kinase B (Akt) activation, which are essential for cell proliferation and survival, were evaluated by immunoblotting.


RESULTS
Both LAs, especially bupivacaine, prevented cell growth and caused cell death in a dose-dependent manner. The half maximal inhibitory concentrations (IC(50)) for bupivacaine and lidocaine were 0.49+/-0.04 and 3.37+/-0.53 mmol/L, respectively. When applied at the same dilutions of commercially available preparations, the apoptotic effect induced by bupivacaine was more severe than that of lidocaine in C2C12 cells. Furthermore, bupivacaine significantly diminished the ERK activation, which may underlie its anti-proliferative actions. Both LAs suppressed Akt activation, which correlated with their effects on apoptosis.


CONCLUSIONS
Our study demonstrated that, when used at the same dilutions from clinically relevant concentrations, bupivacaine is more cytotoxic than lidocaine in vitro. Anti-proliferation and cell death with concomitant apoptosis mediated by bupivacaine may offer an explanation for its adverse effects in vivo (eg slowing wound healing at the surgical sites). A less toxic, long-acting anesthetic may be needed.
Department of Obstetrics and Gynecology, St Joseph's Hospital and Medical Center, Phoenix, AZ, USA.
Joseph M
JM
Maurice
Yan
Y
Gan
Fan-xin
FX
Ma
Yong-chang
YC
Chang
Michael
M
Hibner
Yao
Y
Huang
D000779:Anesthetics, Local / Q000009:adverse effects*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002045:Bupivacaine / Q000009:adverse effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D008012:Lidocaine / Q000009:adverse effects*; D051379:Mice; D032446:Myoblasts / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism
D000779:Anesthetics, Local; D008012:Lidocaine; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D002045:Bupivacaine