Experimental chloroquine myopathy.

Open Access
Publisher Website
Google Scholar
Abstract
A 25 mg/kg of body weight dose of eiloroquine phosphate was administered daily to 6 rabbits in tablet form orally and in. 4 intramuscularly. The number of doses ranged from seven to 42. At sacrifice sections of cerebrum, cerebellum, spinal cord, posterior root ganglia, peri-pheral nerve, heart, kidney, liver, lung and skeletal muscle were microscopically studied. Peripheral nerves were stained, teased and studied microscopically and silver impregnation studies were made on the neuromuscular junction in skeletal muscle. Skeletal muscle samples were also examined histochemically for phosphorylase and succinic dehydrogenase activities. Results showed changes only in the heart and skeletal muscle. Cardiac muscle showed vacuolation of muscle fibers and in some cases necrosis with histiocytic invasion. The changes in cardiac muscle appeared earlier and were more severe than the changes seen in skeletal muscle which consisted primarily of scanty single fiber necrosis with replacement of sarcoplasm by histiocytes. Histochemically there was no significant alteration in the basic distribution of "red" and "white" fibers but the "red" fibers were those predominantly showing damage. Many were shrunken with dark, swollen mitochondria and large sarcolemmal nuclei which were migrating inwards. It is possible that this damage is due to a selective binding of the drug by myohemoglobin.