IMMUNOHISTOCHEMICAL EVIDENCE FOR AMYLOID-BETA IN RAT SOLEUS MUSCLE INCHLOROQUINE-INDUCED MYOPATHY

position of amyloid beta (A beta) is one of the pathological hallmarks of brains affected with Alzheimer's disease (AD). The accumulation of A beta have been observed in human myopathies with rimmed vacuoles (R Vs) which might involve lysosomal function. Chloroquine, a potent lyso somotropic agent, induces muscle pathology in experimental animals sim ilar to myopathy with RV. In this study, we demonstrate, for the first time, immunohistochemical evidence that A beta and cathepsin D, a lys osomal enzyme, accumulate in vacuolated rat soleus muscle due to chlor oquine-induced myopathy. These data indicate that lysosomes are import ant in the metabolism of amyloid precursor protein to generate A beta. This experimental system seems to be useful not only to study basic m echanisms underlying RV myopathy but also to understand processing of amyloid precursor protein to A beta in AD.