Extracellular matrix vesicles were isolated from rat alveolar bone and purified by either gel filtration or discontinuous sucrose density gradient. Morphometric evaluation of electronmicrographs of pellets of purified and nonpurified vesicle fractions was correlated with the acitvity of vesicular enzymes. A high correlation was found between the percentage of area occupied by vesicles with electron-dense content (electron-dense vesicle fractional area) and the enzymatic activity. Highest enzymatic specific activities and electrondense vesicle fractional area were recorded in the "light" vesicle-enriched fraction obtained after equilibrium density centrifugation. These parameters revealed lowest values in the "heavy" vesicle-enriched fraction resolved by the same methods. The combined electron-dense and electron-lucent fractional area (vesicular fractional area) was similar in the different purified fractions. It is therefore suggested that the fraction obtained by gel filtration contains both "light" and "heavy" vesicles. Morphometric study is proposed as an additional criterion for the degree of purification of matrix vesicle preparations.
- Extracellular matrix vesicles
- Vesicular fractional area
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Orthopedics and Sports Medicine