Structural changes in the ageing periosteum using collagen III immuno-staining and chromium labelling as indicators

A. Al-Qtaitat (1,2), R.C. Shore (3), J.E. Aaron (1)

(1) Faculty of Biological Sciences, University of Leeds, UK;
(2) Department of Anatomy and Histology, Faculty of Medicine, Muta’h University, Jordan;
(3) Oral Biology Unit, Dental Institute, University of Leeds, UK

Abstract
The periosteum and Sharpey’s fibre extensions occupy the musculoskeletal interface and may be strategic in age-related deterioration. Because of its exceptionally powerful insertions the porcine mandible is an ideal model and its periosteal system was compared in 4 separate regions of adult young (1 year) and older (3 year) animals. These were examined by undecalcified histology, collagen immunohistochemistry and mineral histochemistry using polarization, epifluorescence and laser confocal microscopy; mineral ultrastructure was facilitated by chromium labelling with EDX microanalysis. Birefringent Sharpey’s fibres were coarse (>8 μm) or fine and classified as horizontal (more common with age), oblique (most common in youth) or vertical (least common); in addition they were designated ‘superficial’, ‘transcortical’ and ‘intertrabecular’ (the latter being deep, coarse and vertical). Their specific affinity for collagen type III FITC-labelled antibody demonstrated 3-dimensional arrays of bonepermeating fibres. With age at each region the cortical thickness rose (e.g. 4.9 mm to 9.3 mm), the periosteum thinned (e.g. 180±7 μm to 129±8 μm; p<0.001), and the periosteum: bone ratio diminished (e.g. 3.65±0.36 to 1.40±0.14; p<0.001) while Sharpey’s fibres became fewer, fragmented, superficial and shortened (e.g. 226±27 μm to 55±6 μm; p<0.001). Accompanying was the sporadic encroachment of calcified particles, 1 μm diameter, in irregular periosteal aggregates or interlinked around Sharpey bundles (resembling calcifying turkey leg tendon). EDX microanalysis confirmed prominent chromium spectral peaks in the older periosteum only, coincident with chromium-labelled mineral ‘ghosts’. It was concluded that the periosteum and Sharpey’s fibres, deep-penetrating and complex in youth, partially hardens and regresses with age with implications for its functional properties.

Keywords: Periosteum and Sharpey’s Fibres, Musculoskeletal Exchange, Ageing Mandible, Collagen Type III Immunohistochemistry, Chromium Staining of Mineral “Ghosts”