Effect of the local doxorubicin injection on the extraocular muscle

Purpose. Doxorubicin(adriamycin) is an effective myotoxic agent for orbicularis oculi muscle in the eyelid after local injection. To investigate the chemomyectomy effect of doxorubicin on extraocular muscle we injected doxorubicin into superior rectus muscle of Rabbits. Methods. For the experimental group, 2mg/ml doxorubicin 0.05ml into right superior rectus muscle and balanced salt solution 0.05ml into left superior rectus muscle for the control group of 12 rabbits. Histologic examinations were done at 1,2,4 and 8 weeks after injection. Results. The number of muscle fiber was decreased and muscle fragmentation and necrosis were found at injection site. Necrotic muscle mass was displaced by interstitial connective tissue and the degree of muscle loss was increased with the lapse of time in the experimental group. There was no conjunctival adhesion or symblepharon and scleral necrosis was not found. Whereas muscle fibers were normally visible and no interstitial connective tissue was found, which were not changed with the lapse of time in the control group. Conclusion. Doxorubicin was also an effective myotoxin to extraocular muscle that it was highly selective to muscle cells and easy to localize within a given muscle and its effect was continuous, so it could be used for nonsurgical treatment of chronic paralytic and restricted form of strabismus.