Increased calcification of growth plate cartilage as a result of compressive force in vitro

Abstract

The influence of intermittent compressive force (ICE') and of continuous compressive force (CCF) on calcification of growth plate cartilage was investigated, using organ cultures of fetal mouse cartilaginous long bone rudiments. Sixteen-day-old metatarsal rudiments, still consisting of uncalcified cartilage, were isolated and cultured for 5 days. Initial calcification of hypertrophic Cartilage occurred under control conditions (atmospheric pressure), and under the influence of ICF or CCF by intermittently or continuously compressing the gas phase above the culture medium. Calcification was monitored by means of 45Ca and 32P incorporation into calcium-phosphate mineral and by morphometric methods. Both ICF and CCF increased cartilage calcification, but ICF was about twice as effective as CCF. Killed rudiiments did not calcify during the culture period, nor did ICF or CCF increase the incorporation of label. The effects of ICF and CCF on calcification could not be mimicked by increasing the Po, and Pcoz levels in the g s phase. The length of the central zone of calcified cartilage was significantly increased by ICF and CCF.W e conclude that hypertrophic chondrocytes respond directly to ICF and CCF by an increased deposition of calcium-phosphate mineral in the matrix. Discontinuous mechanical stimulation evokes a higher cellular response than does continuous stimulation.

Modulation of endochondral development of the distal femoral condyle by mechanical loading

“…21,22,[24][25][26] Experimental data obtained by applying intermittent and continuous compressive forces to the 16-day-old metatarsal rudiment of mouse embryo in organ culture demonstrated that the mineral apposition in the primary ossification site in the center of the metatarsal cartilage rudiment is accelerated, with intermittent forces twice as effective as continuous forces. 27 This study suggests that mechanical stresses accelerate the formation of the primary ossification site during prenatal development. 27 In a follow-up study using finite element modeling, distortional strain was shown to be too small (about 2 microstain) to have stimulated ossification of the 16-day-old embryonic metatarsal rudiment in organ culture; instead, hydrostatic pressure is responsible for the observed epiphyseal ossification.…”

“…27 This study suggests that mechanical stresses accelerate the formation of the primary ossification site during prenatal development. 27 In a follow-up study using finite element modeling, distortional strain was shown to be too small (about 2 microstain) to have stimulated ossification of the 16-day-old embryonic metatarsal rudiment in organ culture; instead, hydrostatic pressure is responsible for the observed epiphyseal ossification. 28 Using a finite element model, Wong and Carter 25,26 postulated that the externally applied hydrostatic pressure, while purely hydrostatic at the rudiment end, produces significant shear stresses at the cartilage/calcified cartilage interface.…”

“…25,26 Furthermore, simulated four-point bending applied to unmineralized and mineralized embryonic mouse ribs at 16 and 17 days of gestational age in a finite element model increases their Young's moduli by two orders of magnitude within 1 day, implicating that the presently used direct loading of chondroepiphysis may result in substantial stress shielding for hypertrophic chondrocytes. 32 Enhanced 45Ca and 32P incorporation in the metatarsal condyle upon both intermittent and continuous compressive hydrostatic pressure in Klein-Nulend and colleagues 27 warrants additional studies to verify whether the formation of the secondary ossification center is accelerated also by hydrostatic pressure, perhaps at different magnitude and durations.…”

The role of mechanical signals in regulating chondrogenesis and osteogenesis of mesenchymal stem cells

“…While the literature describing in vivo and in vitro investigations of the mechanobiology of embryonic limb development is often disjointed and contradictory, a number of important findings clearly establish a central role of mechanical factors. The level of tension experienced by cultured embryonic bone rudiments has been shown to regulate the rate of bone formation (Glucksmann 1939;Glucksmann 1942), while intermittent compression of cultured embryonic mouse long bone rudiments has been shown to increase calcification of the growth plate cartilage (Klein-Nulend et al, 1986). In vitro studies have also demonstrated that cartilaginous tissue in the membrane bones of the embryonic chick will form in response to the mechanical signals generated by movement (Hall 1968).…”

Hydrostatic pressure in combination with topographical cues affects the fate of bone marrow‐derived human mesenchymal stem cells for bone tissue regeneration

“…During movement compressive loading and unloading of hydrated tissues result in changes of the interstitial fluid pressure 26. Hydrostatic pressure has further been shown to enhance mineralization and bone formation when applied to osteoblast‐like cells, cell‐seeded constructs, and ex‐vivo organotypically cultured chick femurs 25, 26, 27…”