Microscarring in skeletal muscle after repeated exposures to lidocaine with epinephrine

To assess the effect of repeated exposures to clinically used local anesthetic, rat thighs were given up to five supramuscular injections of 2% lidocaine with epinephrine, 1:50,000. Substantial damage to muscles followed by rapid regeneration occurred; however, in some areas evidence of retarded regeneration of muscles and microscarring was observed.