Histochemical and electron microscope investigations on medullary bone

Abstract

Folliculin administration to pigeons stimulates the development of medullary bone in marrow spaces of the femora and other long bones. It is a specialized osseus tissue not devoted to mechanical functions and which is rapidly reabsorbed before egg-shell formation. Medullary bone is formed and reabsorbed in the same way as other types of bone. Consequently, because of its very rapid rate of formation and resorption, it represents an ideal tissue for studying osteoblastic, osteoclastic and osteocytic activity, and the calcification process. Medullary bone is deeply stained by PAS, Alcian blue and colloidal iron and is metachromatic after toluidine blue staining. This shows that its interfibrially ground substance contains relatively high amounts of glycoproteins and acid proteoglycans. Calcification initially occurs in maxtrix vesicles (or calcifying globules) which are very numerous between the collagen fibrils of the osteoid tissue, and successively spreads into the surrounding interfibrillar matrix. Here, the crystals are closely related to thin, filament-like organic structures which seem to be components of ground substance proteoglycans. These findings confirm that in medullary bone, as in other types of calcifying tissue, the inorganic substances is initially laid down within calcifying globules and is successively closely related to organic, non-collagenous, filamentous organic structures (crystal ghosts) which probably represent a framework for calcium salt deposition.

Medullary bone-like tissue in the mandibular symphyses of a pterosaur suggests non-reproductive significance

“…According to the phases of the egg-laying cycle, medullary bone can be characterized by rapid formation in the period of maturing follicles, and subsequent rapid destruction during the calcification of the eggshell [10][11][12] . This fast formation-resorption cycle of medullary bone corresponds well with its microanatomy as well as histology: (i) it has large surface areas due to its highly porous, vascularized nature; (ii) its trabeculae are composed of woven bone 6 ; (iii) the number and activity level of osteoclasts is considerably higher in medullary bone than in cortical bone 13 . The composition of medullary bone is similar to that of cortical and cancellous trabecular bone; however, the proportional amount of components are different with medullary bone being more calcified, having higher apatite to collagen ratio, and containing more non-collagenous proteins, proteoglycans and carbohydrates in the matrix 7,12,14,15 .…”

“…Under experimental conditions, administration of these hormones to male birds also results in medullary bone formation [3][4][5] . Growing from the endosteal layers inwards to the medullar cavity, and mostly being composed of woven bone 6 , medullary bone has no mechanical function but serves as a calcium storage that can be quickly mobilized during the calcification of the hard-shelled eggs of birds [6][7][8][9] . According to the phases of the egg-laying cycle, medullary bone can be characterized by rapid formation in the period of maturing follicles, and subsequent rapid destruction during the calcification of the eggshell [10][11][12] .…”

Osteocyte Remodeling of the Perilacunar and Pericanalicular Matrix

“…Belanger, around this same time was also investigating this phenomena and coined the term "osteocytic osteolysis" and published a series of papers suggesting that either parathyroid hormone or low-calcium diet can induce this function in osteocytes (Belanger and Robichon, 1964;Belanger and Drouin, 1966;Belanger, 1969). In renal osteodystrophy, a histologic investigation found a significant increase in the number of enlarged and irregular lacunae in uremic subjects (Bonucci and Gherardi, 1975;Bonucci et al, 1976). In 1977, Iagodovskii et al sent rats into space for a 22-day space flight.…”

Calcified tissue histochemistry: from microstructures to nanoparticles

“…PAS-like methods can be applied in ultrastructural studies of glycoproteins by using, rather than Schiff's reagent, aldehydereactive electron-dense compounds such as alkaline bismuth (Ainsworth et al, 1972) or thiocarbohydrazide-silver proteinate (Scherft 1970;Spicer and Schulte 1982). In electron microscopy, acidic phosphotungstic acid can be used to identify glycoproteins along cell membranes (Marinozzi 1967;Barsotti and Marinozzi 1980) and in calcifying areas (Bonucci and Gherardi 1975; …”

“…This leaves the organic components intact, because they are protected against the dangerous effects of decalcification by being embedded in the resin, as shown by their ultrastructure, which is so well preserved that the tissue seems not to have been decalcified at all (Bonucci 1992b). Histochemical and immunohistochemical reactions are possible after PEDS, provided that the embedding resin is appropriate (Bonucci and Gherardi 1975;Bonucci et al, 1986Bonucci et al, , 1988Bonucci et al, , 1989Goldberg et al, 1980).…”