Effect of surgical trauma on the endogeneous heme iron in the brain
Choudhury, S.R.; Jew, J.; Williams, T.H.
Acta Anatomica 94(4): 545-557
1976
ISSN/ISBN: 0001-5180 PMID: 941672 Document Number: 97338
The fate of endogenous heme Fe, released as a result of planned surgery, in the CNS was studied by EM. During investigations of neuronal plasticity in the cat, an experimental model, in which the proximal cut end of the vagosympathetic trunk was rerouted into the diencephalon, presented an ideal substrate for studying this problem. At 3 mo., the brain tissue containing the implant was processed for light microscopy, EM and histochemistry. Under light microscopy, Prussian-blue-positive, dense cytoplasmic aggregates were visible within the macrophages. The cells were mostly clustered around the junctional area between the central and peripheral nerve elements. EM findings were highly characteristic and distinguished the macrophages from the surrounding neural elements by their rich content of electron-dense granules. While the latter were mostly scattered as free cytoplasmic particles, large aggregates of the same were also observed inside the lysosomes. A few inclusions were also seen within astrocytic processes, close to the plasma membranes. At higher magnifications, the particles revealed the characteristic internal subunit structure of ferritin micelles. The uptake of Hb and its subsequent conversion to ferritin within the macrophages and astrocytic processes were discussed at subcellular level.