Immunocytochemical localization of S-100b protein in degenerating and regenerating rat sciatic nerves.

Abstract

We studied the cellular and subcellular distribution of S-100b protein in normal, crushed, and transected rat sciatic nerves by an immunocytochemical procedure. In uninjured nerves, S-100b protein was restricted to the cytoplasm and membranes of Schwann cells, with no reaction product present in the nucleus or in axons. Similar images were seen from the first to the thirtieth day after the crush in activated Schwann cells during the degeneration period, i.e., up to the seventh post-lesion day, and in normal Schwann cells reappearing during the regeneration period, i.e., after the seventh post-lesion day, in the zone of the crush and proximal and distal to it. By the technique employed, there seemed to be no differences in the intensity of the immune reaction product in normal and activated Schwann cells. Also, similar images were seen in the proximal stump of transected nerves. Only a slight S-100b protein immune reaction product could be observed in the rare activated Schwann cells present in the distal stump around the seventh post-lesion day, the majority of cell types being represented by fibroblasts and elongated cells at this stage and thereafter. By immunochemical assays, similar results as those presented here have been reported and interpreted as indicative of the presence of S-100 protein in axons or, alternatively, of axonal control over expression of S-100 protein in Schwann cells. Our immunocytochemical data clearly show that the strong reduction in the S-100 protein content of the distal stump of transected nerves is owing to the paucity of Schwann cells and to the decrease in the S-100 protein content of these cells, rather than to degeneration of axons.

Immunocytochemical localization of annexin V (CaBP33), a Ca2+‐dependent phospholipid‐and membrane‐binding protein, in the rat nervous system and skeletal muscles and in the porcine heart

“…A similarly diffuse distribution of annexin V has been detected in Schwann cells in peripheral nerves. These localizations of annexin V strongly remind the subcellular localization of S-100 protein, a Ca2'-binding protein of the EF-hand type (for review see Donato, 1991), in the same cell types (Cocchia, 1981;Spreca et al, 1989). However, the amount of annexin Vlg of rat brain turned out to be -20% of that of S-100 protein in the same tissue (Donato, 1986).…”

S‐100 proteins in the human peripheral nervous system

“…The expression of S100 protein in Schwann cells and sensory corpuscles is regulated by Schwann-related cell-axonic contact (DeLeon et al, 1991;Del Valle et al, 1993;Perez and Moore, 1968;Spreca et al 1989). In humans we demonstrated that nerve entrapment and section severely modifies the expression of S100 proteins by Meissner corpuscles.…”

Structure and Function of the Myelin Proteins: Current Status and Perspectives in Relation to Multiple Sclerosis

“…They are believed to participate in the regulation of energy metabolism, the regulation of cell shape and polarity, and intracellular calcium-regulated signal transduction [164]. The 10 kDa calcium-and zinc-binding [165][166][167] S100 protein is present in the cytoplasm and associated with plasma membranes of myelinating Schwann cells [168]. It is absent from compact myelin membranes [168,169], but is present at the Schmidt-Lanterman incisures and in the paranodal loops [169].…”