Three-dimensional structural interrelations between cells, extracellular matrix, and mineral in normally mineralizing avian leg tendon.
The spatial-temporal relationship between cells, extracellular matrices, and mineral deposits is fundamental for an improved understanding of mineralization mechanisms in vertebrate tissues. By utilizing focused ion beam-scanning electron microscopy with serial surface imaging, normally mineralizing avian tendons have been studied with nanometer resolution in three dimensions with volumes exceeding tens of micrometers in range. These parameters are necessary to yield sufficiently fine ultrastructural details while providing a comprehensive overview of the interrelationships between the tissue structural constituents. Investigation reveals a complex lacuno-canalicular network in highly mineralized tendon regions, where ∼100 nm diameter canaliculi emanating from cell (tenocyte) lacunae surround extracellular collagen fibril bundles. Canaliculi are linked to smaller channels of ∼40 nm diameter, occupying spaces between fibrils. Close to the tendon mineralization front, calcium-rich deposits appear between the fibrils and, with time, mineral propagates along and within them. These close associations between tenocytes, tenocyte lacunae, canaliculi, small channels, collagen, and mineral suggest a concept for the mineralization process, where ions and/or mineral precursors may be transported through spaces between fibrils before they crystallize along the surface of and within the fibrils.
['Zou|Zhaoyong|Z|', 'Tang|Tengteng|T|0000-0002-6417-5892', 'Macías-Sánchez|Elena|E|0000-0003-1569-8088', 'Sviben|Sanja|S|', 'Landis|William J|WJ|0000-0002-1944-0220', 'Bertinetti|Luca|L|0000-0002-4666-9610', 'Fratzl|Peter|P|']
D000818:Animals D000077320:Biomineralization D002118:Calcium D003094:Collagen D005109:Extracellular Matrix D021621:Imaging, Three-Dimensional D035002:Lower Extremity D008297:Male D013710:Tendons D000070916:Tenocytes D014422:Turkeys
lacuno-canalicular network FIB-SEM biomineralization inter- and intrafibrillar mineralization