Lysosomes in normal and degenerating neuroblasts of the chick embryo spinal ganglia. A cytochemical and quantitative study by electron microscopy.

Lysosomes were studied by both cytochemical and quantitative methods in normal and degenerating neuroblasts of the chick embryo spinal ganglia. In normal neuroblasts (primitive and intermediate neuroblasts) both primary lysosomes and autophagic vacuoles were found; these organelles were usually located in the region containing the Golgi complex. In degenerating neuroblasts lysosomes appeared sharply decreased in number with respect to normal neuroblasts. Moreover, lysosomes were always evident as intact organelles surrounded by a membrane and the acid phosphatase activity appeared localized exclusively within these bodies. A diffuse distribution of acid phosphatase activity was only found in a limited number of cases during the terminal stage of the process. Possibly in these cases the enzymatic activity depended on the cells which enveloped the degenerated neuroblast remnants. The present results indicate that lysosomes do not play a primary role in the degenerative process studied.