The lysosomal enzymes acid phosphatase and cathepsin D in rats intoxicatedwith Senna occidentalis seeds

Chronic administration of Senna occidentalis seeds induces an experimental toxic myopathy characterized by skeletal muscle fibers atrophy, decrease in histochemical activity of cytochrome oxidase, and increase of the acid pho sphatase activity in muscle fibres at the light microscopic level. The mech anisms that lead to the increase of this lysosomal enzyme activity are not known and could be related to other biochemical disturbs than the mitochond rial function impairment. The main aim of the present: study is to localize the acid phosphatase activity using a cytochemical method at transmission electron microscopy level and to quantify cathepsin D in muscle of rats chr onically intoxicated with Senna occidentalis seeds by immunoblotting. Acid phosphatase was observed in lysosomes and over profiles of some organelles apparently not involved by lysosomal membrane. In addition immunoblotting d emonstrated a decrease in the content of the precursor and of the mature fo rm of cathepsin D in samples of muscles and liver of intoxicated animals. W e concluded that there is a selective increase in acid phosphatase activity in muscle - and maybe in other tissues - of animals intoxicated with Senna occidentalis, that can be related to the skeletal muscle atrophy and the i ntense decrease in weight gain of these animals. Further studies should be performed to establish the mechanisms of selectivity in increase of lysosom al enzymes in different situations and pathological stares.