Acute effect of bupivacaine and ricin mAb 35 on extraocular muscle in the rabbit.
OBJECTIVE
To identify acute histologic change of extraocular muscles induced by bupivacaine or ricin mAb 35 injection.


METHODS
The superior rectus and inferior rectus of white rabbits were injected with bupivacaine (0.4 mg in 0.3 ml) or ricin mAb 35 (0.2 microg/kg in 0.3 ml). After 1, 2, and 4 weeks, the rectus muscles were harvested, and postinjection changes in the muscle layers were examined histopathologically.


RESULTS
Bupivacaine and ricin mAb 35 induced myotoxic changes in both the orbital and the global layers. However, the inflammation and the myofiber destruction produced by bupivacaine injection was localized to the injection site, which compared with the diffuse change induced by ricin mAb 35. Inflammation reduced rapidly over 2 weeks. Regenerating myofibers with a central nucleus were found at 1 week after injecting these myotoxins. Four weeks after injection, the acute changes induced by these two toxins respectively were much recovered with prominent myofiber regeneration.


CONCLUSIONS
We found that extraocular muscle has a superb ability to recover from the acute injury induced by bupivacaine or ricin mAb 35, and the two myotoxins induce unique damage including the predilection of muscle layers and duration of damage persisted. Further investigation about the functional change during recovery from the myotoxin-induced injury of extraocular muscles is needed.
Park
Choul Yong
CY
Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
Park
Sung Eun
SE
Oh
Sei Yeul
SY
D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D000911:Antibodies, Monoclonal; D002045:Bupivacaine / Q000494:pharmacology*; D000922:Immunotoxins / Q000494:pharmacology*; D007273:Injections, Intramuscular; D009210:Myofibrils / Q000187:drug effects; D009801:Oculomotor Muscles / Q000187:drug effects* / Q000473:pathology; D011817:Rabbits; D011978:Receptors, Nicotinic / Q000276:immunology; D012276:Ricin / Q000494:pharmacology*
D000779:Anesthetics, Local; D000911:Antibodies, Monoclonal; D000922:Immunotoxins; D011978:Receptors, Nicotinic; D012276:Ricin; D002045:Bupivacaine