Effect of disuse osteoporosis on bone composition: the fate of bone matrix

Abstract

Disuse bone atrophy was induced in 10 adult dogs by means of brachial plexus section and/or elbow disarticulation. After 9 to 12 weeks of disuse intact humeri were examined by X-ray, and their physical properties determined. The whole humeri were isolated, defatted, dried to constant weight, and their mineral and collagen content determined.Eight out of 10 experimental (non-ueed) humeri demonstrated evidence of decreased radiodensity. The non-used limb demonstrated parallel loss in dry, fat-free weight (--23.2 % ), in collagen (--25.3 %), and in mineral (--26.1% ), as compared to the normal limb. The data indicated that the major portion of the lost bone tissue in disuse osteoporosis is replaced by water, fat, and other unidentified organic materials rather than fibrous tissue, and that collagen is lost in equal proportion to mineral. The proportionately greater loss of collagen and mineral than of dry, fat-free weight appears to be due to an increase of non-collagenous, non-lipid organic material, presumably protein.Atrophic osseuse d'immobilisation 6fair induite par section de la plexus brachial et/ou Immobilisations-Knochenatrophie wurde in 10 erwachsenen Hunden herbeigefiihrt dutch Brachialplexusschnitt und/oder Ellenbogenexartikulation. Nach 9--12 Wochen der Immobilisation wurden die intakten Humeri unter R6ntgenstrahlen untersucht und ihre physischen Eigenschaften bestimmt. Der intakte Humerus wurde isoliert, entfettet, zu konstantem Gewicht getrocknet und der Knochenaschengehalt und Kollagengehalt bestimmt.Acht der 10 experimentellen (immobilisierten) Humeri demonstrierten Beweis yon verringerter R5ntgendichte. Die immobilisierte Extremit~it zeigte ~ihnlichen Verlust in trockenem, fettfreiem Gewicht (--23,2%) in Kollagen (--25,3%) und Knochenasche (--26,1%) im Vergleich zur normalen Extremit~t. Die Daten deuten an, dal3 der Hauptanteil des Verlustes

Intravital bone imaging by two-photon excitation microscopy to identify osteocytic osteolysis in vivo

“…Sciatic neurectomy (SNR) has been reported as a means of inducing severe osteoporosis [26,27]. As in previous studies, we also demonstrated significantly lower bone density in the proximal tibiae from 10 days after SNR than in sham-operated mice by μCT (Fig.…”

“…Ten-week-old female C57BL/6 mice were subjected to unilateral sciatic neurectomy (SNR) or sham surgery (day 0) under isoflurane-induced anesthesia. SNR consisted of resecting a 3-to 4-mm segment of the right sciatic nerve posterior to the hip joint [26,27]. For sham surgery, the same procedure was performed without resection.…”

Prevention of ligament and meniscus atrophy by active joint motion in a non–weight‐bearing model

“…Our initial report on disuse induced by disarticulation in dogs (14) did not measure the effect of disuse on soft tissues. The present study attempts to correlate collagen resorption and net mass in soft tissues with bone-ligament-bone strength, and bone resorption and net mass of bone in an ankle disarticulated model of immobilization.…”

Treatment of denervation/disuse osteoporosis in the rat with a capacitively coupled electrical signal: Effects on bone formation and bone resorption

“…In recent years the work of several investigators has suggested that during the development of disuse osteoporosis, bone resorption is accelerated, while lation. Disuse osteoporosis can be produced in laboratory animals by the immobilization of an extremity through casting, denervation, or a combination of the two (1,4,(6)(7)(8)(9)(10)(11)(12)15,17,18,(20)(21)(22)(23)(24)26,27). In rats a reproducible osteoporosis develops in the ipsilateral tibia over 28 days following sciatic denervation (4,5, 25).…”