Expression of calcium binding proteins in the developing spine: preliminary report

Previous ultrastructural studies on the developing spine induced the Authors to analyse the presence of Ca-binding proteins in the vertebral anlagen of the chick embryo, by immunostaining for calretinin. At 7 incubation days, intense positivity for calretinin at level of the intervertebral region is detectable. From the 7th day the positivity is localized in particular to the intervertebral menisci and it appears also in the degenerating chondrocytes of the chondrifying vertebrae and at level of the peripheral zones of vascular erosion in the ossifying vertebrae. The intervertebral positivity for calretinin can be related to the presence at this level of fibroblast-like cells, that for such immunoreactivity are distinguishable from true fibroblasts. Since other Authors showed presence of S-100 protein in fibroblast-like cells during histogenesis of white adipose tissue, the significance of the expression of some Ca-binding proteins in the differentiation of these cell types can be supposed. The meaning of the immunoreactivity in the vertebral bodies is still uncertain and needs further immunohistochemical studies.