ABSTRACT

The aim of this study was to investigate the myotoxic effects of bupivacaine, ropivacaine, and

levobupivacaine which were applied intramuscularly to rat skeletal muscle. Forty Wistar-Albino rats were

divided into four groups. In the study, .5% bupivacaine (Group B), .5% ropivacaine (Group R), .5%

levobupivacaine (Group L), or .9% normal saline (Group SF) was applied intramuscularly to the right

gastrocnemius muscle of rats. The rats in each group were sacrificed on the second day after injection.

Sections of muscle samples were stained with hematoxylin–eosin for light microscopic investigation and

prepared for the evaluation of ultrastructural changes in the subcellular level with transmission electron

microscopy. All three local anesthetic agents caused qualitatively similar skeletal muscle damage. The most

observed muscle damage was in Group B, muscle damage of Group R was less than that of Group B, and the

least damage was seen in Group L quantitatively. Electron microscopic examination of each group that

caused cellular damage was qualitatively similar. The most subcellular damage was observed in the group

receiving bupivacaine, less was seen in the ropivacaine group, and the least was observed in the

levobupivacaine group. The results indicated that bupivacaine caused more myotoxic damage than the other

two agents in the skeletal muscle of rats and that levobupivacaine caused less myotoxic damage than both

bupivacaine and ropivacaine at the cell and tissue levels.

Keywords:

Local anesthetic, myotoxicity, transmission electron microscopy

Histological changes caused by local anesthetics in the

striated muscle tissue were described for the first time

by Brun in 1959 [1]. Drug- and dose-dependent

myonecrosis of skeletal muscle tissue and the consequent

severe muscular dysfunction due to the

application of